SMSC FDC37B778 Enhanced super i/o controller with wake up feature Datasheet

FDC37B77x
ADVANCED INFORMATION
Enhanced Super I/O Controller with Wake-Up Features
and Consumer IR
FEATURES
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5 Volt Operation
PC98/99 and ACPI 1.0 Compliant
ISA Plug-and-Play Compatible Register Set
Intelligent Auto Power Management
Shadowed Write-Only Registers
Programmable Wake-up Event
Interface
System Management Interrupt, Watchdog
Timer
2.88MB Super I/O Floppy Disk Controller
Licensed CMOS 765B Floppy Disk
Controller
Software and Register Compatible
with SMSC's Proprietary 82077AA
Compatible Core
Supports One Floppy Drive
Configurable Open Drain/Push-Pull
Output Drivers
Supports Vertical Recording Format
16-Byte Data FIFO
100% IBM Compatibility
Detects All Overrun and Underrun
Conditions
Sophisticated Power Control Circuitry
(PCC) Including Multiple Powerdown
Modes for Reduced Power
Consumption
DMA Enable Logic
Data Rate and Drive Control Registers
480 Address, Up to Eight IRQ and
Three DMA Options
Floppy Disk Available on Parallel Port Pins
Enhanced Digital Data Separator
-
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2 Mbps, 1 Mbps, 500 Kbps, 300
Kbps, 250 Kbps Data Rates
Programmable Precompensation
Modes
Keyboard Controller
8042 Software Compatible
8 Bit Microcomputer
2k Bytes of Program ROM
256 Bytes of Data RAM
Four Open Drain Outputs Dedicated
for Keyboard/Mouse Interface
Asynchronous Access to Two Data
Registers and One Status Register
Supports Interrupt and Polling Access
8 Bit Counter Timer
Port 92 Support
Fast Gate A20 and KRESET Outputs
8042 P12 and P16 Outputs
Serial Ports
Two Full Function Serial Ports
High Speed NS16C550 Compatible
UARTs with Send/Receive 16-Byte
FIFOs
Supports 230k and 460k Baud
Programmable Baud Rate Generator
Modem Control Circuitry
480 Address and 15 IRQ Options
Infrared Port
Multiprotocol Infrared Interface
32-Byte Data FIFO
IrDA 1.0 Compliant
Consumer IR
SHARP ASK IR
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480 Address, Up to 15 IRQ and Three
DMA Options
Multi-Mode Parallel Port with ChiProtect
Standard Mode IBM PC/XT PC/AT,
and PS/2 Compatible Bidirectional
Parallel Port
Enhanced Parallel Port (EPP)
Compatible - EPP 1.7 and EPP 1.9
(IEEE 1284 Compliant)
IEEE 1284 Compliant Enhanced
Capabilities Port (ECP)
ChiProtect Circuitry for Protection
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Against Damage Due to Printer PowerOn
480 Address, Up to 15 IRQ and
Three DMA Options
ISA Host Interface
16 Bit Address Qualification
8 Bit Data Bus
IOCHRDY for ECP and IrCC
Three 8 Bit DMA Channels
Serial IRQ Interface Compatible with
Serialized IRQ Support for PCI Systems
PCI PME Interface
100 Pin QFP Package
GENERAL DESCRIPTION
up events. The PCC supports multiple low
power-down modes.
The FDC37B77x with advanced Consumer IR
and IrDA v1.0 support incorporates a keyboard
interface, SMSC's true CMOS 765B floppy disk
controller, advanced digital data separator, two
16C550A compatible UARTs, one Multi-Mode
parallel port which includes ChiProtect circuitry
plus EPP and ECP, on-chip 12 mA AT bus
drivers, one floppy direct drive support, and
Intelligent Power Management including PME
support. The true CMOS 765B core provides
100% compatibility with IBM PC/XT and PC/AT
architectures in addition to providing data
overflow and underflow protection. The SMSC
advanced digital data separator incorporates
SMSC's patented data separator technology,
allowing for ease of testing and use. Both onchip UARTs are compatible with the
NS16C550A. The parallel port is compatible
with IBM PC/AT architecture, as well as IEEE
1284 EPP and ECP. The FDC37B77x
incorporates sophisticated power control circuitry
(PCC) which includes support for keyboard,
mouse, modem ring and consumer infrared
wake-
The FDC37B77x supports the ISA Plug-and-Play
Standard (Version 1.0a) and provides the
recommended functionality to support Windows
'95.
The I/O Address, DMA Channel and
hardware IRQ of each logical device in the
FDC37B77x may be reprogrammed through the
internal configuration registers. There are 480
I/O address location options, a Serialized IRQ
interface, and three DMA channels.
The FDC37B77x does not require any external
filter components and is therefore easy to use
and offers lower system costs and reduced
board area. The FDC37B77x is software and
register compatible with SMSC's proprietary
82077AA core.
2
TABLE OF CONTENTS
FEATURES ......................................................................................................................... 1
GENERAL DESCRIPTION .................................................................................................. 2
PIN CONFIGURATION........................................................................................................ 5
DESCRIPTION OF PIN FUNCTIONS .................................................................................. 6
DESCRIPTION OF MULTIFUNCTION PINS ......................................................................10
REFERENCE DOCUMENTS ..............................................................................................10
FUNCTIONAL DESCRIPTION............................................................................................12
SUPER I/O REGISTERS ................................................................................................12
HOST PROCESSOR INTERFACE .................................................................................12
FLOPPY DISK CONTROLLER ..........................................................................................13
FDC INTERNAL REGISTERS ........................................................................................13
COMMAND SET/DESCRIPTIONS......................................................................................36
INSTRUCTION SET ...........................................................................................................40
SERIAL PORT (UART).......................................................................................................66
INFRARED INTERFACE ....................................................................................................80
PARALLEL PORT ..............................................................................................................81
IBM XT/AT COMPATIBLE, BI-DIRECTIONAL AND EPP MODES ..................................83
EXTENDED CAPABILITIES PARALLEL PORT...............................................................90
PARALLEL PORT FLOPPY DISK CONTROLLER ..........................................................104
POWER MANAGEMENT..................................................................................................106
VTR SUPPORT ..............................................................................................................106
SERIAL IRQ .....................................................................................................................112
GP INDEX REGISTERS ...................................................................................................117
WATCH DOG TIMER .......................................................................................................119
8042 KEYBOARD CONTROLLER DESCRIPTION ..........................................................120
SYSTEM MANAGEMENT INTERRUPT (SMI)..................................................................129
PME SUPPORT............................................................................................................129
CONFIGURATION............................................................................................................131
OPERATIONAL DESCRIPTION.......................................................................................160
MAXIMUM GUARANTEED RATINGS* .........................................................................160
3
DC ELECTRICAL CHARACTERISTICS........................................................................160
TIMING DIAGRAMS .........................................................................................................165
ECP PARALLEL PORT TIMING ......................................................................................186
80 Arkay Dr.
Hauppauge, NY 11788
(631) 435-6000
FAX: (631) 273-3123
4
FDC37B77x
100 PIN QFP
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
nCS/SA11
PCI_CLK
SER_IRQ
nIOR
nIOW
AEN
SD0
SD1
SD2
SD3
VSS
SD4
SD5
SD6
SD7
RESET_DRV
nDACK1
DRQ2
nDACK2
DRQ1
DRVDEN0
DRVDEN1
nMTRO
nPME
nDS0
CLOCK132
VSS
nD IR
nSTEP
nWDATA
nWGATE
nHDSEL
nINDEX
nTRK0
nWRTPRT
nRDATA
nDSKCHG
VTR
CLOCKI
SA0
SA1
SA2
SA3
SA4
SA5
SA6
SA7
SA8
SA9
SA10
100
99
98
97
96
95
94
93
92
91
90
89
88
87
86
85
84
83
82
81
nDTR2/SA14
nCTS2/SA13
nRTS2/SA12
nDSR2/SA15
TXD2/IRTX
RXD2/IRRX
nDCD2/P12
VCC
nRI2/P16
nDCD1
nRI1
nDTR1
nCTS1
nRTS1/SYSOP
nDSR1
TXD1
RXD1
nSTROBE
nALF
nERROR
PIN CONFIGURATION
5
80
79
78
77
76
75
74
73
72
71
70
69
68
67
66
65
64
63
62
61
60
59
58
57
56
55
54
53
52
51
nACK
BUSY
PE
SLCT
VSS
PD7
PD6
PD5
PD4
PD3
PD2
PD1
PD0
nSLCTIN
nINIT
VCC
A20M
KBDR ST
IRTX
IRRX
VSS
MCLK
MDAT
KCLK
KDAT
I OCHRDY
TC
VCC
DRQ3/P12
nDACK3/P16
DESCRIPTION OF PIN FUNCTIONS
PIN
No./QFP
37:40,
42:45
20:30
31
36
55
46
33
32
50
48
52
47
49
51
54
34
35
4
6
19
61
62
53,65,
93
7,41,
60,76
18
NAME
TOTAL
SYMBOL
PROCESSOR/HOST INTERFACE (36)
System Data Bus
8
SD[0:7]
11-bit System Address Bus
Chip Select/SA11 (Note 1)
Address Enable
I/O Channel Ready
ISA Reset Drive
Serial IRQ
PCI Clock for Serial IRQ (33MHz/30MHz)
DMA Request 1
DMA Request 2
DMA Request 3/8042 P12
DMA Acknowledge 1
DMA Acknowledge 2
DMA Acknowledge 3/8042 P16
11
1
1
1
1
1
1
1
1
1
1
1
1
Terminal Count
I/O Read
I/O Write
Power Management Event
32.768 Trickle Clock Input
1
1
1
1
1
CLOCKS (1)
14.318MHz Clock Input
1
INFRARED INTERFACE (2)
Infrared Rx
1
Infrared Tx (Note 4), (Note 5)
1
POWER PINS (8)
Power
SA[0:10]
nCS/SA11
AEN
IOCHRDY
RESET_DRV
SER_IRQ
PCI_CLK
DRQ1
DRQ2
DRQ3/P12
nDACK1
nDACK2
nDACK3/
P16
TC
nIOR
nIOW
nPME
CLOCK132
CLOCKI
IRRX
IRTX
VCC
Ground
VSS
Trickle Voltage
VTR
6
BUFFER
TYPE
IO12
I
I
I
OD12
IS
IO12
ICLK
O12
O12
O12/IO12
I
I
I/IO12
I
I
I
OD24
ICLK
ICLK
I
O24PD
DESCRIPTION OF PIN FUNCTIONS
PIN
No./QFP
NAME
TOTAL
SYMBOL
BUFFER
TYPE
FDD INTERFACE (14)
16
11
10
12
8
9
17
5
3
15
14
13
1
2
84
85
87
88
89
86
91
90
95
96
98
99
100
Read Disk Data
1
Write Gate
1
Write Disk Data
1
Head Select
1
Step Direction
1
Step Pulse
1
Disk Change
1
Drive Select 0
1
Motor On 0
1
Write Protected
1
Track 0
1
Index Pulse Input
1
Drive Density Select 0
1
Drive Density Select 1
1
SERIAL PORT 1 INTERFACE (8)
Receive Serial Data 1
1
Transmit Serial Data 1
1
Request to Send 1
1
Clear to Send 1
1
Data Terminal Ready 1
1
Data Set Ready 1
1
Data Carrier Detect 1
1
Ring Indicator 1
1
SERIAL PORT 2 INTERFACE (8)
Receive Serial Data 2/Infrared Rx
1
Transmit Serial Data 2/Infrared Tx (Note 4,
1
Note 7)
Request to Send 2/Sys Addr 12 (Note 6)
1
Clear to Send 2/Sys Addr 13
1
Data Terminal Ready/Sys Addr 14 (Note 6)
1
7
nRDATA
nWGATE
nWDATA
nHDSEL
nDIR
nSTEP
nDSKCHG
nDS0
nMTR0
nWRTPRT
nTRKO
nINDEX
DRVDEN0
DRVDEN1
RXD1
TXD1
nRTS1/
SYSOP
nCTS1
nDTR1
nDSR1
nDCD1
nRI1
IS
O24/OD24
O24/OD24
O24/OD24
O24/OD24
O24/OD24
IS
O24/OD24
O24/OD24
IS
IS
IS
O24/OD24
O24/OD24
I
O4
O4/I
I
O4
I
I
I
RXD2/IRRX
TXD2/IRTX
I
O24PD
nRTS2/SA12
nCTS2/SA13
nDTR2/
SA14
O4/I
I/I
O4/I
DESCRIPTION OF PIN FUNCTIONS
PIN
No./QFP
97
NAME
Data Set Ready 2/Sys Addr 15
TOTAL
1
94
92
Data Carrier Detect 2/8042 P12
Ring Indicator 2/8042 P16
1
1
56
57
58
59
63
PARALLEL PORT INTERFACE (17)
Parallel Port Data Bus
8
Printer Select
1
Initiate Output
1
Auto Line Feed
1
Strobe Signal
1
Busy Signal
1
Acknowledge Handshake
1
Paper End
1
Printer Selected
1
Error at Printer
1
KEYBOARD/MOUSE INTERFACE (6)
Keyboard Data
1
Keyboard Clock
1
Mouse Data
1
Mouse Clock
1
Keyboard Reset
1
64
Gate A20
68:75
67
66
82
83
79
80
78
77
81
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
Note 6:
1
SYMBOL
nDSR2/
SA15
nDCD2/P12
nRI2/P16
PD[0:7]
nSLCTIN
nINIT
nALF
nSTROBE
BUSY
nACK
PE
SLCT
nERROR
KDAT
KCLK
MDAT
MCLK
KBDRST
(Note 3)
A20M
BUFFER
TYPE
I/I
I/IO24
I/IO24
IO24
OD24/O24
OD24/O24
OD24/O24
OD24/O24
I
I
I
I
I
IOD16
IOD16
IOD16
IOD16
O4
O4
For 12 bit addressing, SA0:SA11 only, nCS should be tied to GND. For 16 bit external
address qualification, address bits SA11:SA15 can be "ORed" together and applied to nCS.
The nCS pin functions as SA11 in full 16 bit Internal Address Qualification Mode. CR24.6
controls the FDC37B77x addressing modes.
The "n" as the first letter of a signal name indicates an "Active Low" signal.
KBDRST is active low.
The pull-down on this pin is always active including when the output driver is tristated
and regardless of the state of internal PWRGOOD.
The “activate” bit for the CIrCC is reset by VTR POR only. The VCC power-up default for
this pin is Logic “0”.
The “activate” bit for Serial Port 2 is reset by VTR POR only. The VCC power-up default for
this pin is Logic “1”.
8
Note 7:
The “activate” bit for Serial Port 2 (CIrCC) is reset by VTR POR only. The VCC power-up
default for this pin is Logic “1”. Do not use this pin for infrared transceivers that are
transmit active high.
Buffer Type Descriptions
I
IS
IOD16
IO24
IO4
O4
O24
OD24
ICLK
IO12
O12
OD12
O24PD
Input, TTL compatible.
Input with Schmitt trigger.
Input/Open Drain Output, 16mA sink.
Input/Output, 24mA sink, 12mA source.
Input/Output, 4mA sink, 2mA source.
Output, 4mA sink, 2mA source.
Output, 24mA sink, 12mA source.
Output, Open Drain, 24mA sink.
Clock Input
Input/Output, 12mA sink, 6mA source
Output, 12mA sink, 6mA source
Output, Open Drain, 12 mA sink
Output, 12mA sink, 6mA source with 30 µA pull-down
9
DESCRIPTION OF MULTIFUNCTION PINS
Note 1:
Note 2:
Note 3:
Note 4:
PIN
ORIGINAL
ALTERNATE
NO./QFP FUNCTION
FUNCTION 1
DEFAULT
nDACK3
8042 P16
nDACK3
51
DRQ3
8042 P12
DRQ3
52
nRI2
8042 P16
nRI2
92
nDCD2
8042 P12
nDCD2
94
RXD2
IRRX
RXD2
95
TXD2
IRTX
TXD2
96
nDSR2
SA15
nDSR2
97
nRTS2
SA12
nRTS2
98
nCTS2
SA13
nCTS2
99
nDTR2
SA14
nDTR2
100
Controlled by DMA3SEL(LD8:CRC0.1)
Controlled by 8042COMSEL(LD8:CRC0.3)
Controlled by IR Option Register( LD5:CRF1.6)
Controlled by 16 bit Address Qualification (CR24.6)
NOTE
1
1
2
2
3
3
4
4
4
4
For more information, refer to tables 63 through 73.
REFERENCE DOCUMENTS
1.
2.
3.
4.
SMSC Consumer Infrared Communications Controller (CIrCC) V1.X
IEEE 1284 Extended Capabilities Port Protocol and ISA Standard, Rev. 1.14, July 14, 1993.
Hardware Description of the 8042, Intel 8 bit Embedded Controller Handbook.
PCI Bus Power Management Interface Specification, Rev. 1.0, Draft, March 18, 1997.
10
nPME
PME
SMI
WDT
DATA BUS
SER_IRQ
PCI_CLK
MULTI-MODE
PARALLEL
PORT/FDC
MUX
PD0-7
BUSY, SLCT, PE,
nERROR, nACK
nSTB, nSLCTIN,
nINIT, nALF
SERIAL
IRQ
ADDRESS BUS
nIOR
CONFIGURATION
REGISTERS
nIOW
AEN
16C550
COMPATIBLE
SERIAL
PORT 1
TXD1, nCTS1, nRTS1
RXD1
nDSR1, nDCD1, nRI1, nDTR1
SA[0:12] (nCS) *
SA[13-15] *
CONTROL BUS
HOST
CPU
SD[O:7]
WDATA
INTERFACE
DRQ[1:3]
WCLOCK
*
16C550
COMPATIBLE
SERIAL
PORT 2 WITH
INFRARED
TC
RESET_DRV
nDSR2, nDCD2, nRI2, nDTR2*
8042
IOCHRDY
TXD2(IRTX), nCTS2, nRTS2*
RXD2(IRRX)*
SMSC
PROPRIETARY
DIGITAL
DATA
82077
SEPARATOR
COMPATIBLE
WITH
WRITE
VERTICAL
PRECOMFLOPPYDISK
PENSATION
CONTROLLER
CORE
RCLOCK
nDACK[1:3] *
IRRX, IRTX
RDATA
CLOCK
KCLK
KDATA
MCLK
MDATA
GATEA20, KRESET
P12*, P16*
GEN
VTR Vcc Vss
nINDEX DENSEL nDS0
nTRK0 nDIR nMTR0
nWDATAnRDATA
nDSKCHG
nSTEP DRVDEN0
nWRPRT
*
nHDSEL DRVDEN1
CLK32 CLOCKI
32KHz 14MHz nWGATE
* Denotes Multifunction Pins
FIGURE 1 - FDC37B77x BLOCK DIAGRAM
11
FUNCTIONAL DESCRIPTION
SUPER I/O REGISTERS
HOST PROCESSOR INTERFACE
The address map, shown below in Table 1,
shows the addresses of the different blocks of
the Super I/O immediately after power up. The
base addresses of the FDC, serial and parallel
ports can be moved via the configuration
registers. Some addresses are used to access
more than one register.
The host processor communicates with the
FDC37B77x through a series of read/write
registers. The port addresses for these registers
are shown in Table 1. Register access is
accomplished through programmed I/O or DMA
transfers. All registers are 8 bits wide. All host
interface output buffers are capable of sinking a
minimum of 12 mA.
Table 1 - Super I/O Block Addresses
LOGICAL
ADDRESS
BLOCK NAME
DEVICE
Base+(0-5) and +(7)
Floppy Disk
0
Base+(0-7)
Serial Port Com 1
4
Base1+(0-7)
Base2+(0-7)
Serial Port Com 2
5
Parallel Port
SPP
EPP
ECP
ECP+EPP+SPP
3
Base+(0-3)
Base+(0-7)
Base+(0-3), +(400-402)
Base+(0-7), +(400-402)
60, 64
KYBD
7
NOTES
IR Support
Fast IR
Note 1: Refer to the configuration register descriptions for setting the base address
12
FLOPPY DISK CONTROLLER
FDC INTERNAL REGISTERS
The Floppy Disk Controller (FDC) provides the
interface between a host microprocessor and
the floppy disk drives. The FDC integrates the
functions of the Formatter/Controller, Digital
Data Separator, Write Precompensation and
Data Rate Selection logic for an IBM XT/AT
compatible FDC. The true CMOS 765B core
guarantees 100% IBM PC XT/AT compatibility
in addition to providing data overflow and
underflow protection.
The Floppy Disk Controller contains eight
internal registers which facilitate the interfacing
between the host microprocessor and the disk
drive. Table 2 shows the addresses required to
access these registers. Registers other than the
ones shown are not supported. The rest of the
description assumes that the primary addresses
have been selected.
The FDC is compatible to the 82077AA using
SMSC's proprietary floppy disk controller core.
PRIMARY
ADDRESS
3F0
3F1
3F2
3F3
3F4
3F4
3F5
3F6
3F7
3F7
Table 2 - Status, Data and Control Registers
(Shown with base addresses of 3F0 and 370)
SECONDARY
ADDRESS
R/W
REGISTER
370
R
Status Register A (SRA)
371
R
Status Register B (SRB)
372
R/W
Digital Output Register (DOR)
373
R/W
Tape Drive Register (TSR)
374
R
Main Status Register (MSR)
374
W
Data Rate Select Register (DSR)
375
R/W
Data (FIFO)
376
Reserved
377
R
Digital Input Register (DIR)
377
W
Configuration Control Register (CCR)
13
interface pins in PS/2 and Model 30 modes. The
SRA can be accessed at any time when in PS/2
mode. In the PC/AT mode the data bus pins D0
- D7 are held in a high impedance state for a
read of address 3F0.
STATUS REGISTER A (SRA)
Address 3F0 READ ONLY
This register is read-only and monitors the state
of the FINTR
pin
and
several
disk
PS/2 Mode
RESET
COND.
7
INT
PENDING
0
6
nDRV2
5
STEP
1
0
4
3
2
nTRK0 HDSEL nINDX
N/A
0
N/A
1
nWP
0
DIR
N/A
0
BIT 4 nTRACK 0
Active low status of the TRK0 disk interface
input.
BIT 0 DIRECTION
Active high status indicating the direction of
head movement. A logic "1" indicates inward
direction; a logic "0" indicates outward direction.
BIT 5 STEP
Active high status of the STEP output disk
interface output pin.
BIT 1 nWRITE PROTECT
Active low status of the WRITE PROTECT disk
interface input. A logic "0" indicates that the disk
is write protected.
BIT 6 nDRV2
Active low status of the DRV2 disk interface
input pin, indicating that a second drive has
been installed. Note: This function is not
supported in the FDC37B77x.
BIT 2 nINDEX
Active low status of the INDEX disk interface
input.
BIT 7 INTERRUPT PENDING
Active high bit indicating the state of the Floppy
Disk Interrupt output.
BIT 3 HEAD SELECT
Active high status of the HDSEL disk interface
input. A logic "1" selects side 1 and a logic "0"
selects side 0.
14
PS/2 Model 30 Mode
RESET
COND.
7
INT
PENDING
0
6
DRQ
0
5
STEP
F/F
0
4
3
TRK0 nHDSEL
N/A
1
2
INDX
1
WP
0
nDIR
N/A
N/A
1
BIT 4 TRACK 0
Active high status of the TRK0 disk interface
input.
BIT 0 nDIRECTION
Active low status indicating the direction of head
movement. A logic "0" indicates inward
direction; a logic "1" indicates outward direction.
BIT 5 STEP
Active high status of the latched STEP disk
interface output pin. This bit is latched with the
STEP output going active, and is cleared with a
read from the DIR register, or with a hardware
or software reset.
BIT 1 WRITE PROTECT
Active high status of the WRITE PROTECT disk
interface input. A logic "1" indicates that the disk
is write protected.
BIT 2 INDEX
Active high status of the INDEX disk interface
input.
BIT 6 DMA REQUEST
Active high status of the DRQ output pin.
BIT 7 INTERRUPT PENDING
Active high bit indicating the state of the Floppy
Disk Interrupt output.
BIT 3 nHEAD SELECT
Active low status of the HDSEL disk interface
input. A logic "0" selects side 1 and a logic "1"
selects side 0.
15
Model 30 modes. The SRB can be accessed at
any time when in PS/2 mode. In the PC/AT
mode the data bus pins D0 - D7 are held in a
high impedance state for a read of address 3F1.
STATUS REGISTER B (SRB)
Address 3F1 READ ONLY
This register is read-only and monitors the state
of several disk interface pins in PS/2 and
PS/2 Mode
RESET
COND.
7
1
6
1
1
1
5
4
3
2
DRIVE WDATA RDATA WGATE
SEL0 TOGGLE TOGGLE
0
0
0
0
1
MOT
EN1
0
0
MOT
EN0
0
BIT 4 WRITE DATA TOGGLE
Every inactive edge of the WDATA input causes
this bit to change state.
BIT 0 MOTOR ENABLE 0
Active high status of the MTR0 disk interface
output pin. This bit is low after a hardware reset
and unaffected by a software reset.
BIT 5 DRIVE SELECT 0
Reflects the status of the Drive Select 0 bit of
the DOR (address 3F2 bit 0). This bit is cleared
after a hardware reset and it is unaffected by a
software reset.
BIT 1 MOTOR ENABLE 1
Active high status of the MTR1 disk interface
output pin. This bit is low after a hardware reset
and unaffected by a software reset. Note: In the
FDC37B77x only one drive is available at the
FDD interface.
BIT 6 RESERVED
Always read as a logic "1".
BIT 2 WRITE GATE
Active high status of the WGATE disk interface
output.
BIT 7 RESERVED
Always read as a logic "1".
BIT 3 READ DATA TOGGLE
Every inactive edge of the RDATA input causes
this bit to change state.
16
PS/2 Model 30 Mode
RESET
COND.
7
nDRV2
6
nDS1
5
nDS0
N/A
1
1
4
WDATA
F/F
0
3
RDATA
F/F
0
2
WGATE
F/F
0
1
nDS3
0
nDS2
1
1
BIT 4 WRITE DATA
Active high status of the latched WDATA output
signal. This bit is latched by the inactive going
edge of WDATA and is cleared by the read of
the DIR register. This bit is not gated with
WGATE.
BIT 0 nDRIVE SELECT 2
The DS2 disk interface is not supported in the
FDC37B77x.
BIT 1 nDRIVE SELECT 3
The DS3 disk interface is not supported in the
FDC37B77x.
BIT 5 nDRIVE SELECT 0
Active low status of the DS0 disk interface
output.
BIT 2 WRITE GATE
Active high status of the latched WGATE output
signal. This bit is latched by the active going
edge of WGATE and is cleared by the read of
the DIR register.
BIT 6 nDRIVE SELECT 1
Active low status of the DS1 disk interface
output.
BIT 3 READ DATA
Active high status of the latched RDATA output
signal. This bit is latched by the inactive going
edge of RDATA and is cleared by the read of the
DIR register.
BIT 7 nDRV2
Active low status of the DRV2 disk interface
input. Note: This function is not supported in
the FDC37B77x.
17
DIGITAL OUTPUT REGISTER (DOR)
also contains the enable for the DMA logic and a
software reset bit. The contents of the DOR are
unaffected by a software reset. The DOR can
be written to at any time.
Address 3F2 READ/WRITE
The DOR controls the drive select and motor
enables of the disk interface outputs. It
RESET
COND.
7
MOT
EN3
0
6
MOT
EN2
0
5
MOT
EN1
0
4
MOT
EN0
0
3
2
1
0
DMAEN nRESE DRIVE DRIVE
T
SEL1
SEL0
0
0
0
0
BIT 0 and 1 DRIVE SELECT
These two bits are binary encoded for the drive
selects, thereby allowing only one drive to be
selected at one time.
BIT 4 MOTOR ENABLE 0
This bit controls the MTR0 disk interface output.
A logic "1" in this bit will cause the output pin to
go active.
BIT 2 nRESET
A logic "0" written to this bit resets the Floppy
disk controller. This reset will remain active
until a logic "1" is written to this bit. This
software reset does not affect the DSR and CCR
registers, nor does it affect the other bits of the
DOR register. The minimum reset duration
required is 100ns, therefore toggling this bit by
consecutive writes to this register is a valid
method of issuing a software reset.
BIT 5 MOTOR ENABLE 1
This bit controls the MTR1 disk interface output.
A logic "1" in this bit will cause the output pin to
go active.
BIT 6 MOTOR ENABLE 2
The MTR2 disk interface output is not supported
in the FDC37B77x.
BIT 7 MOTOR ENABLE 3
The MTR3 disk interface output is not supported
in the FDC37B77x.
BIT 3 DMAEN
PC/AT and Model 30 Mode:
Writing this bit to logic "1" will enable the DRQ,
nDACK, TC and FINTR outputs. This bit being
a logic "0" will disable the nDACK and TC
inputs, and hold the DRQ and FINTR outputs in
a high impedance state. This bit is a logic "0"
after a reset and in these modes.
Table 3 - Drive Activation Values
PS/2 Mode: In this mode the DRQ, nDACK, TC
and FINTR pins are always enabled. During a
reset, the DRQ, nDACK, TC, and FINTR pins
will remain enabled, but this bit will be cleared to
a logic "0".
18
DRIVE
DOR VALUE
0
1
1CH
2DH
TAPE DRIVE REGISTER (TDR)
Table 4 - Tape Select Bits
Address 3F3 READ/WRITE
The Tape Drive Register (TDR) is included for
82077 software compatibility and allows the
user to assign tape support to a particular drive
during initialization. Any future references to
that drive automatically invokes tape support.
The TDR Tape Select bits TDR.[1:0] determine
the tape drive number. Table 4 illustrates the
Tape Select Bit encoding. Note that drive 0 is
the boot device and cannot be assigned tape
support. The remaining Tape Drive Register
bits TDR.[7:2] are tristated when read. The TDR
is unaffected by a software reset.
TAPE SEL1
(TDR.1)
TAPE SEL0
(TDR.0)
DRIVE
SELECTED
0
0
1
1
0
1
0
1
None
1
2
3
Table 5 - Internal 2 Drive Decode - Normal
DRIVE SELECT
MOTOR ON OUTPUTS
DIGITAL OUTPUT REGISTER
OUTPUTS (ACTIVE LOW)
(ACTIVE LOW)
Bit 7 Bit 6 Bit 5 Bit 4 Bit1 Bit 0
nDS1
nDS0
nMTR1
nMTR0
X
X
X
1
0
0
1
0
nBIT 5
nBIT 4
X
X
1
X
0
1
0
1
nBIT 5
nBIT 4
X
1
X
X
1
0
1
1
nBIT 5
nBIT 4
1
X
X
X
1
1
1
1
nBIT 5
nBIT 4
0
0
0
0
X
X
1
1
nBIT 5
nBIT 4
Table 6 - Internal 2 Drive Decode - Drives 0 and 1 Swapped
DRIVE SELECT OUTPUTS MOTOR ON OUTPUTS
DIGITAL OUTPUT REGISTER
(ACTIVE LOW)
(ACTIVE LOW)
Bit 7 Bit 6 Bit 5 Bit 4 Bit1 Bit 0
nDS1
nDS0
nMTR1
nMTR0
X
X
X
1
0
0
0
1
nBIT 4
nBIT 5
X
X
X
1
X
0
1
1
0
nBIT 4
nBIT 5
1
X
X
1
0
1
1
nBIT 4
nBIT 5
1
X
X
X
1
1
1
1
nBIT 4
nBIT 5
0
0
0
0
X
X
1
1
nBIT 4
nBIT 5
19
Normal Floppy Mode
Normal mode. Register 3F3 contains only bits 0 and 1. When this register is read, bits 2 - 7 are a
high impedance.
REG 3F3
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
Tri-state
Tri-state
Tri-state
Tri-state
Tri-state
Tri-state
tape sel1
tape sel0
DB3
DB2
DB1
DB0
tape sel1
tape sel0
Enhanced Floppy Mode 2 (OS2)
Register 3F3 for Enhanced Floppy Mode 2 operation.
DB7
DB6
DB5
REG 3F3 Reserved Reserved
DB4
Drive Type ID
Floppy Boot Drive
Table 7 - Drive Type ID
DIGITAL OUTPUT REGISTER
REGISTER 3F3 - DRIVE TYPE ID
Note:
Bit 1
Bit 0
Bit 5
Bit 4
0
0
L0-CRF2 - B1
L0-CRF2 - B0
0
1
L0-CRF2 - B3
L0-CRF2 - B2
1
0
L0-CRF2 - B5
L0-CRF2 - B4
1
1
L0-CRF2 - B7
L0-CRF2 - B6
L0-CRF2-Bx = Logical Device 0, Configuration Register F2, Bit x.
20
30 and Microchannel applications.
Other
applications can set the data rate in the DSR.
The data rate of the floppy controller is the most
recent write of either the DSR or CCR. The DSR
is unaffected by a software reset. A hardware
reset will set the DSR to 02H, which
corresponds to the default precompensation
setting and 250 Kbps.
DATA RATE SELECT REGISTER (DSR)
Address 3F4 WRITE ONLY
This register is write only. It is used to program
the data rate, amount of write precompensation,
power down status, and software reset. The
data
rate
is
programmed
using
the
Configuration Control Register (CCR) not the
DSR,
for
PC/AT
and
PS/2
Model
RESET
COND.
7
6
S/W POWER
RESET DOWN
0
0
5
0
0
4
PRECOMP2
0
3
PRECOMP1
0
2
1
0
PRE- DRATE DRATE
COMP0 SEL1
SEL0
0
1
0
BIT 7 SOFTWARE RESET
This active high bit has the same function as the
DOR RESET (DOR bit 2) except that this bit is
self clearing.
BIT 0 and 1 DATA RATE SELECT
These bits control the data rate of the floppy
controller.
See Table 11 for the settings
corresponding to the individual data rates. The
data rate select bits are unaffected by a
software reset, and are set to 250 Kbps after a
hardware reset.
BIT 2 through 4
PRECOMPENSATION
SELECT
These three bits select the value of write
precompensation that will be applied to the
WDATA output signal. Table 10 shows the
precompensation values for the combination of
these bits settings. Track 0 is the default
starting track number to start precompensation.
this starting track number can be changed by
the configure command.
BIT 5 UNDEFINED
Should be written as a logic "0".
BIT 6 LOW POWER
A logic "1" written to this bit will put the floppy
controller into manual low power mode. The
floppy controller clock and data mode after a
software reset or access to the Data Register or
Main Status Register.
Note: The DSR is Shadowed in the Floppy Data
Rate Select Shadow Register, LD8:CRC2[7:0].
separator circuits will be turned off.
The
controller will come out of manual low power.
Table 8 - Precompensation Delays
PRECOMP
432
111
001
010
011
100
101
110
000
PRECOMPENSATION
DELAY (nsec)
<2Mbps
2Mbps*
0.00
41.67
83.34
125.00
166.67
208.33
250.00
Default
0
20.8
41.7
62.5
83.3
104.2
125
Default
Default: See Table 12
*2Mbps data rate is only available if VCC = 5V.
21
DRIVE RATE
Table 9 - Data Rates
DATA RATE
DATA RATE
DRATE(1)
DENSEL
DRT1
DRT0
SEL1
SEL0
MFM
FM
1
0
0
0
1
1
1Meg
---
1
1
1
0
0
0
0
500
250
1
0
0
0
0
0
1
300
150
0
0
1
0
0
1
0
250
125
0
1
0
0
1
1
1
1Meg
---
1
1
1
0
1
0
0
500
250
1
0
0
0
1
0
1
500
250
0
0
1
0
1
1
0
250
125
0
1
0
1
0
1
1
1Meg
---
1
1
1
1
0
0
0
500
250
1
0
0
1
0
0
1
2Meg
---
0
0
1
1
0
1
0
250
125
0
1
0
Drive Rate Table (Recommended) 00 = 360K, 1.2M, 720K, 1.44M and 2.88M Vertical Format
01 = 3-Mode Drive
10 = 2 Meg Tape
Note 1: The DRATE and DENSEL values are mapped onto the DRVDEN pins.
Table 10 - DRVDEN Mapping
DRVDEN1 (1)
DRVDEN0 (1)
DRIVE TYPE
DRATE0
DENSEL
4/2/1 MB 3.5"
2/1 MB 5.25" FDDS
2/1.6/1 MB 3.5" (3-MODE)
DT1
0
DT0
0
1
0
DRATE0
DRATE1
0
1
DRATE0
nDENSEL
1
1
DRATE1
DRATE0
22
PS/2
Table 11 - Default Precompensation Delays
DATA RATE
PRECOMPENSATION
DELAYS
2 Mbps*
1 Mbps
500 Kbps
300 Kbps
250 Kbps
20.8 ns
41.67 ns
125 ns
125 ns
125 ns
*The 2Mbps data rate is only available if VCC = 5V.
23
time.
The MSR indicates when the disk
controller is ready to receive data via the Data
Register. It should be read before each byte
transferring to or from the data register except in
DMA mode. No delay is required when reading
the MSR after a data transfer.
MAIN STATUS REGISTER
Address 3F4 READ ONLY
The Main Status Register is a read-only register
and indicates the status of the disk controller.
The Main Status Register can be read at any
7
6
5
4
RQM
DIO
NON
DMA
CMD
BUSY
3
2
Reserved Reserved
1
0
DRV1
BUSY
DRV0
BUSY
BIT 5 NON-DMA
This mode is selected in the SPECIFY
command and will be set to a 1 during the
execution phase of a command. This is for
polled data transfers and helps differentiate
between the data transfer phase and the reading
of result bytes.
BIT 0 - 1 DRV x BUSY
These bits are set to 1s when a drive is in the
seek portion of a command, including implied
and overlapped seeks and recalibrates.
BIT 4 COMMAND BUSY
This bit is set to a 1 when a command is in
progress. This bit will go active after the
command byte has been accepted and goes
inactive at the end of the results phase. If there
is no result phase (Seek, Recalibrate
commands), this bit is returned to a 0 after the
last command byte.
BIT 6 DIO
Indicates the direction of a data transfer once a
RQM is set. A 1 indicates a read and a 0
indicates a write is required.
BIT 7 RQM
Indicates that the host can transfer data if set to
a 1. No access is permitted if set to a 0.
24
FIFO. The data is based upon the following
formula:
DATA REGISTER (FIFO)
Address 3F5 READ/WRITE
All command parameter information, disk data
and result status are transferred between the
host processor and the floppy disk controller
through the Data Register.
Threshold # x
1
DATA RATE
x8
At the start of a command, the FIFO action is
always disabled and command parameters
must be sent based upon the RQM and DIO bit
settings. As the command execution phase is
entered, the FIFO is cleared of any data to
ensure that invalid data is not transferred.
Data transfers are governed by the RQM and
DIO bits in the Main Status Register.
The Data Register defaults to FIFO disabled
mode after any form of reset. This maintains
PC/AT hardware compatibility.
The default
values can be changed through the Configure
command (enable full FIFO operation with
threshold control). The advantage of the FIFO
is that it allows the system a larger DMA latency
without causing a disk error. Table 14 gives
several examples of the delays with a
An overrun or underrun will terminate the
current command and the transfer of data. Disk
writes will complete the current sector by
generating a 00 pattern and valid CRC. Reads
require the host to remove the remaining data
so that the result phase may be entered.
Table 12 - FIFO Service Delay
FIFO THRESHOLD
MAXIMUM DELAY TO SERVICING AT 2
EXAMPLES
Mbps* DATA RATE
1 byte
2 bytes
8 bytes
15 bytes
FIFO THRESHOLD
EXAMPLES
1 byte
2 bytes
8 bytes
15 bytes
FIFO THRESHOLD
EXAMPLES
1 byte
2 bytes
8 bytes
15 bytes
- 1.5 µs = DELAY
1 x 4 µs - 1.5 µs = 2.5 µs
2 x 4 µs - 1.5 µs = 6.5 µs
8 x 4 µs - 1.5 µs = 30.5 µs
15 x 4 µs - 1.5 µs = 58.5 µs
MAXIMUM DELAY TO SERVICING AT 1
Mbps DATA RATE
1 x 8 µs - 1.5 µs = 6.5 µs
2 x 8 µs - 1.5 µs = 14.5 µs
8 x 8 µs - 1.5 µs = 62.5 µs
15 x 8 µs - 1.5 µs = 118.5 µs
MAXIMUM DELAY TO SERVICING AT
500 Kbps DATA RATE
1 x 16 µs - 1.5 µs = 14.5 µs
2 x 16 µs - 1.5 µs = 30.5 µs
8 x 16 µs - 1.5 µs = 126.5 µs
15 x 16 µs - 1.5 µs = 238.5 µs
*The 2 Mbps data rate is only available if VCC = 5V.
25
DIGITAL INPUT REGISTER (DIR)
Address 3F7 READ ONLY
This register is read-only in all modes.
PC-AT Mode
RESET
COND.
7
DSK
CHG
N/A
6
5
4
3
2
1
0
N/A
N/A
N/A
N/A
N/A
N/A
N/A
BIT 7 DSKCHG
This bit monitors the pin of the same name and
reflects the opposite value seen on the disk
cable or the value programmed in the Force
Disk Change Register (see Configuration
Register LD8:CRC1[1:0]).
BIT 0 - 6 UNDEFINED
The data bus outputs D0 - 6 will remain in a
high impedance state during a read of this
register.
PS/2 Mode
RESET
COND.
7
DSK
CHG
N/A
6
1
5
1
4
1
3
1
N/A
N/A
N/A
N/A
BIT 0 nHIGH DENS
This bit is low whenever the 500 Kbps or 1 Mbps
data rates are selected, and high when 250
Kbps and 300 Kbps are selected.
2
1
0
DRATE DRATE nHIGH
SEL1
SEL0 nDENS
N/A
N/A
1
BITS 3 - 6 UNDEFINED
Always read as a logic "1"
BIT 7 DSKCHG
This bit monitors the pin of the same name and
reflects the opposite value seen on the disk
cable or the value programmed in the Force
Disk Change Register (see Configuration
Register LD8:CRC1[1:0]).
BITS 1 - 2 DATA RATE SELECT
These bits control the data rate of the floppy
controller.
See Table 11 for the settings
corresponding to the individual data rates. The
data rate select bits are unaffected by a
software reset, and are set to 250 Kbps after a
hardware reset.
26
Model 30 Mode
RESET
COND.
7
DSK
CHG
N/A
6
0
5
0
4
0
0
0
0
3
2
1
0
DMAEN NOPREC DRATE DRATE
SEL1
SEL0
0
0
1
0
BIT 3 DMAEN
This bit reflects the value of DMAEN bit set in
the DOR register bit 3.
BITS 0 - 1 DATA RATE SELECT
These bits control the data rate of the floppy
controller.
See Table 11 for the settings
corresponding to the individual data rates. The
data rate select bits are unaffected by a
software reset, and are set to 250 Kbps after a
hardware reset.
BITS 4 - 6 UNDEFINED
Always read as a logic "0"
BIT 7 DSKCHG
This bit monitors the pin of the same name and
reflects the opposite value seen on the disk
cable or the value programmed in the Force
Disk Change Register (see Configuration
Register LD8:CRC1[1:0]).
BIT 2 NOPREC
This bit reflects the value of NOPREC bit set in
the CCR register.
27
CONFIGURATION
(CCR)
CONTROL
REGISTER
Address 3F7 WRITE ONLY
PC/AT and PS/2 Modes
RESET
COND.
7
6
5
4
3
2
N/A
N/A
N/A
N/A
N/A
N/A
1
0
DRATE DRATE
SEL1
SEL0
1
0
BIT 2 - 7 RESERVED
Should be set to a logical "0"
BIT 0 and 1 DATA RATE SELECT 0 and 1
These bits determine the data rate of the floppy
controller. See Table 11 for the appropriate
values.
PS/2 Model 30 Mode
RESET
COND.
7
6
5
4
3
N/A
N/A
N/A
N/A
N/A
BIT 0 and 1 DATA RATE SELECT 0 and 1
These bits determine the data rate of the floppy
controller. See Table 11 for the appropriate
values.
2
1
0
NOPREC DRATE DRATE
SEL1
SEL0
N/A
1
0
BIT 3 - 7 RESERVED
Should be set to a logical "0"
Table 12 shows the state of the DENSEL pin.
The DENSEL pin is set high after a hardware
reset and is unaffected by the DOR and the
DSR resets.
BIT 2 NO PRECOMPENSATION
This bit can be set by software, but it has no
functionality. It can be read by bit 2 of the DSR
when in Model 30 register mode. Unaffected by
software reset.
28
STATUS REGISTER ENCODING
During the Result Phase of certain commands, the Data Register contains data bytes that give the
status of the command just executed.
BIT NO.
SYMBOL
Table 13 - Status Register 0
NAME
DESCRIPTION
7,6
IC
Interrupt
Code
00 - Normal termination of command. The specified
command was properly executed and completed
without error.
01 - Abnormal termination of command. Command
execution was started, but was not successfully
completed.
10 - Invalid command. The requested command
could not be executed.
11 - Abnormal termination caused by Polling.
5
SE
Seek End
The FDC completed a Seek, Relative Seek or
Recalibrate command (used during a Sense Interrupt
Command).
4
EC
Equipment
Check
The TRK0 pin failed to become a "1" after:
1. 80 step pulses in the Recalibrate command.
2. The Relative Seek command caused the FDC to
step outward beyond Track 0.
H
Head
Address
The current head address.
DS1,0
Drive Select
The current selected drive.
3
2
1,0
Unused. This bit is always "0".
29
BIT NO.
7
SYMBOL
EN
Table 14 - Status Register 1
NAME
DESCRIPTION
End of
Cylinder
6
The FDC tried to access a sector beyond the final
sector of the track (255D). Will be set if TC is not
issued after Read or Write Data command.
Unused. This bit is always "0".
5
DE
Data Error
The FDC detected a CRC error in either the ID field or
the data field of a sector.
4
OR
Overrun/
Underrun
Becomes set if the FDC does not receive CPU or DMA
service within the required time interval, resulting in
data overrun or underrun.
3
Unused. This bit is always "0".
2
ND
No Data
Any one of the following:
1. Read Data, Read Deleted Data command - the
FDC did not find the specified sector.
2. Read ID command - the FDC cannot read the ID
field without an error.
3. Read A Track command - the FDC cannot find the
proper sector sequence.
1
NW
Not Writeable WP pin became a "1" while the FDC is executing a
Write Data, Write Deleted Data, or Format A Track
command.
0
MA
Missing
Any one of the following:
Address Mark 1. The FDC did not detect an ID address mark at the
specified track after encountering the index pulse
from the IDX pin twice.
2. The FDC cannot detect a data address mark or a
deleted data address mark on the specified track.
30
BIT NO.
SYMBOL
Table 15 - Status Register 2
NAME
DESCRIPTION
7
Unused. This bit is always "0".
6
CM
Control Mark
Any one of the following:
1. Read Data command - the FDC encountered a
deleted data address mark.
2. Read Deleted Data command - the FDC
encountered a data address mark.
5
DD
Data Error in
Data Field
The FDC detected a CRC error in the data field.
4
WC
Wrong
Cylinder
The track address from the sector ID field is different
from the track address maintained inside the FDC.
3
Unused. This bit is always "0".
2
Unused. This bit is always "0".
1
BC
Bad Cylinder
The track address from the sector ID field is different
from the track address maintained inside the FDC and
is equal to FF hex, which indicates a bad track with a
hard error according to the IBM soft-sectored format.
0
MD
Missing Data The FDC cannot detect a data address mark or a
Address Mark deleted data address mark.
31
BIT NO.
SYMBOL
Table 16- Status Register 3
NAME
DESCRIPTION
7
6
Unused. This bit is always "0".
WP
Write
Protected
5
4
Unused. This bit is always "1".
T0
Track 0
3
2
1,0
Indicates the status of the WP pin.
Indicates the status of the TRK0 pin.
Unused. This bit is always "1".
HD
Head
Address
Indicates the status of the HDSEL pin.
DS1,0
Drive Select
Indicates the status of the DS1, DS0 pins.
RESET
DOR Reset vs. DSR Reset (Software Reset)
There are three sources of system reset on the
FDC: the RESET pin of the FDC, a reset
generated via a bit in the DOR, and a reset
generated via a bit in the DSR. At power on, a
Power On Reset initializes the FDC. All resets
take the FDC out of the power down state.
These two resets are functionally the same.
Both will reset the FDC core, which affects drive
status information and the FIFO circuits. The
DSR reset clears itself automatically while the
DOR reset requires the host to manually clear it.
DOR reset has precedence over the DSR reset.
The DOR reset is set automatically upon a pin
reset. The user must manually clear this reset
bit in the DOR to exit the reset state.
All operations are terminated upon a RESET,
and the FDC enters an idle state. A reset while
a disk write is in progress will corrupt the data
and CRC.
MODES OF OPERATION
On exiting the reset state, various internal
registers are cleared, including the Configure
command information, and the FDC waits for a
new command. Drive polling will start unless
disabled by a new Configure command.
The FDC has three modes of operation, PC/AT
mode, PS/2 mode and Model 30 mode. These
are determined by the state of the IDENT and
MFM bits 6 and 5 respectively of CRxx.
PC/AT mode - (IDENT high, MFM a "don't
care")
RESET Pin (Hardware Reset)
The RESET pin is a global reset and clears all
registers except those programmed by the
Specify command.
The DOR reset bit is
enabled and must be cleared by the host to exit
the reset state.
The PC/AT register set is enabled, the DMA
enable bit of the DOR becomes valid (FINTR
and DRQ can be hi Z), and TC and DENSEL
become active high signals.
32
PS/2 mode - (IDENT low, MFM high)
This mode supports the PS/2 models 50/60/80
configuration and register set. The DMA bit of
the DOR becomes a "don't care", (FINTR and
DRQ are always valid), TC and DENSEL
become active low.
Burst mode is enabled via Bit[1] of CRF0 in
Logical Device 0. Setting Bit[1]=0 enables burst
mode; the default is Bit[1]=1, for non-burst
mode.
Model 30 mode - (IDENT low, MFM low)
This mode supports PS/2 Model 30
configuration and register set. The DMA enable
bit of the DOR becomes valid (FINTR and DRQ
can be hi Z), TC is active high and DENSEL is
active low.
For simplicity, command handling in the FDC
can be divided into three phases: Command,
Execution, and Result. Each phase is described
in the following sections.
DMA TRANSFERS
After a reset, the FDC enters the command
phase and is ready to accept a command from
the host. For each of the commands, a defined
set of command code bytes and parameter
bytes has to be written to the FDC before the
command phase is complete. (Please refer to
Table 19 for the command set descriptions).
These bytes of data must be transferred in the
order prescribed.
CONTROLLER PHASES
Command Phase
DMA transfers are enabled with the Specify
command and are initiated by the FDC by
activating the FDRQ pin during a data transfer
command. The FIFO is enabled directly by
asserting nDACK and addresses need not be
valid.
Note that if the DMA controller (i.e. 8237A) is
programmed to function in verify mode, a
pseudo read is performed by the FDC based
only on nDACK. This mode is only available
when the FDC has been configured into byte
mode (FIFO disabled) and is programmed to do
a read. With the FIFO enabled, the FDC can
perform the above operation by using the new
Verify command; no DMA operation is needed.
Before writing to the FDC, the host must
examine the RQM and DIO bits of the Main
Status Register. RQM and DIO must be equal
to "1" and "0" respectively before command
bytes may be written. RQM is set false by the
FDC after each write cycle until the received
byte is processed. The FDC asserts RQM again
to request each parameter byte of the command
unless an illegal command condition is
detected.
After the last parameter byte is
received, RQM remains "0" and the FDC
automatically enters the next phase as defined
by the command definition.
The FDC37B77x supports two DMA transfer
modes for the FDC: Single Transfer and Burst
Transfer. In the case of the single transfer, the
DMA Req goes active at the start of the DMA
cycle, and the DMA Req is deasserted after the
nDACK. In the case of the burst transfer, the
Req is held active until the last transfer
(independent of nDACK). See timing diagrams
for more information.
The FIFO is disabled during the command
phase to provide for the proper handling of the
"Invalid Command" condition.
33
until the last byte is transferred out of the FIFO.
The FDC will deactivate the FINT pin and RQM
bit when the FIFO becomes empty.
Execution Phase
All data transfers to or from the FDC occur
during the execution phase, which can proceed
in DMA or non-DMA mode as indicated in the
Specify command.
Non-DMA Mode - Transfers from the Host to the
FIFO
The FINT pin and RQM bit in the Main Status
Register are activated upon entering the
execution phase of data transfer commands.
The host must respond to the request by writing
data into the FIFO. The FINT pin and RQM bit
remain true until the FIFO becomes full. They
are set true again when the FIFO has
<threshold> bytes remaining in the FIFO. The
FINT pin will also be deactivated if TC and
nDACK both go inactive. The FDC enters the
result phase after the last byte is taken by the
FDC from the FIFO (i.e. FIFO empty condition).
After a reset, the FIFO is disabled. Each data
byte is transferred by an FINT or FDRQ
depending on the DMA mode. The Configure
command can enable the FIFO and set the
FIFO threshold value.
The following paragraphs detail the operation of
the FIFO flow control. In these descriptions,
<threshold> is defined as the number of bytes
available to the FDC when service is requested
from the host and ranges from 1 to 16. The
parameter FIFOTHR, which the user programs,
is one less and ranges from 0 to 15.
DMA Mode - Transfers from the FIFO to the
Host
A low threshold value (i.e. 2) results in longer
periods of time between service requests, but
requires faster servicing of the request for both
read and write cases. The host reads (writes)
from (to) the FIFO until empty (full), then the
transfer request goes inactive. The host must
be very responsive to the service request. This
is the desired case for use with a "fast" system.
The FDC activates the DDRQ pin when the
FIFO contains (16 - <threshold>) bytes, or the
last byte of a full sector transfer has been
placed in the FIFO. The DMA controller must
respond to the request by reading data from the
FIFO. The FDC will deactivate the DDRQ pin
when the FIFO becomes empty. FDRQ goes
inactive after nDACK goes active for the last
byte of a data transfer (or on the active edge of
nIOR, on the last byte, if no edge is present on
nDACK). A data underrun may occur if FDRQ
is not removed in time to prevent an unwanted
cycle.
A high value of threshold (i.e. 12) is used with a
"sluggish" system by affording a long latency
period after a service request, but results in
more frequent service requests.
Non-DMA Mode - Transfers from the FIFO to
the Host
DMA Mode - Transfers from the Host to the
FIFO.
The FINT pin and RQM bits in the Main Status
Register are activated when the FIFO contains
(16-<threshold>) bytes or the last bytes of a full
sector have been placed in the FIFO. The FINT
pin can be used for interrupt-driven systems,
and RQM can be used for polled systems. The
host must respond to the request by reading
data from the FIFO. This process is repeated
The FDC activates the FDRQ pin when entering
the execution phase of the data transfer
commands. The DMA controller must respond
by activating the nDACK and nIOW pins and
placing data in the FIFO. FDRQ remains active
until the FIFO becomes full. FDRQ is again set
34
status indications can be ignored if they were
expected.
true when the FIFO has <threshold> bytes
remaining in the FIFO. The FDC will also
deactivate the FDRQ pin when TC becomes true
(qualified by nDACK), indicating that no more
data is required. FDRQ goes inactive after
nDACK goes active for the last byte of a data
transfer (or on the active edge of nIOW of the
last byte, if no edge is present on nDACK). A
data overrun may occur if FDRQ is not removed
in time to prevent an unwanted cycle.
Note that when the host is sending data to the
FIFO of the FDC, the internal sector count will
be complete when the FDC reads the last byte
from its side of the FIFO. There may be a delay
in the removal of the transfer request signal of
up to the time taken for the FDC to read the last
16 bytes from the FIFO. The host must tolerate
this delay.
Data Transfer Termination
Result Phase
The FDC supports terminal count explicitly
through the TC pin and implicitly through the
underrun/overrun and end-of-track (EOT)
functions. For full sector transfers, the EOT
parameter can define the last sector to be
transferred in a single or multi-sector transfer.
The generation of FINT determines the
beginning of the result phase. For each of the
commands, a defined set of result bytes has to
be read from the FDC before the result phase is
complete. These bytes of data must be read out
for another command to start.
If the last sector to be transferred is a partial
sector, the host can stop transferring the data in
mid-sector, and the FDC will continue to
complete the sector as if a hardware TC was
received. The only difference between these
implicit functions and TC is that they return
"abnormal termination" result status.
Such
RQM and DIO must both equal "1" before the
result bytes may be read. After all the result
bytes have been read, the RQM and DIO bits
switch to "1" and "0" respectively, and the CB bit
is cleared, indicating that the FDC is ready to
accept the next command.
35
is issued. The user sends a Sense Interrupt
Status command which returns an invalid
command error.
Refer to Table 17 for
explanations of the various symbols used. Table
18 lists the required parameters and the results
associated with each command that the FDC is
capable of performing.
COMMAND SET/DESCRIPTIONS
Commands can be written whenever the FDC is
in the command phase. Each command has a
unique set of needed parameters and status
results. The FDC checks to see that the first
byte is a valid command and, if valid, proceeds
with the command. If it is invalid, an interrupt
Table 17 - Description of Command Symbols
SYMBOL
NAME
DESCRIPTION
C
Cylinder Address
The currently selected address; 0 to 255.
D
Data Pattern
The pattern to be written in each sector data field during
formatting.
D0, D1
Drive Select 0-1
Designates which drives are perpendicular drives on the
Perpendicular Mode Command. A "1" indicates a perpendicular
drive.
DIR
Direction Control
If this bit is 0, then the head will step out from the spindle during a
relative seek. If set to a 1, the head will step in toward the spindle.
DS0, DS1
Disk Drive Select
DS1
DS0
DRIVE
0
0
0
1
Drive 0
Drive 1
DTL
Special Sector
Size
By setting N to zero (00), DTL may be used to control the number
of bytes transferred in disk read/write commands. The sector size
(N = 0) is set to 128. If the actual sector (on the diskette) is larger
than DTL, the remainder of the actual sector is read but is not
passed to the host during read commands; during write
commands, the remainder of the actual sector is written with all
zero bytes. The CRC check code is calculated with the actual
sector. When N is not zero, DTL has no meaning and should be
set to FF HEX.
EC
Enable Count
When this bit is "1" the "DTL" parameter of the Verify command
becomes SC (number of sectors per track).
EFIFO
Enable FIFO
This active low bit when a 0, enables the FIFO. A "1" disables the
FIFO (default).
EIS
Enable Implied
Seek
When set, a seek operation will be performed before executing any
read or write command that requires the C parameter in the
command phase. A "0" disables the implied seek.
EOT
End of Track
The final sector number of the current track.
36
Table 17 - Description of Command Symbols
SYMBOL
NAME
GAP
DESCRIPTION
Alters Gap 2 length when using Perpendicular Mode.
GPL
Gap Length
The Gap 3 size. (Gap 3 is the space between sectors excluding
the VCO synchronization field).
H/HDS
Head Address
Selected head: 0 or 1 (disk side 0 or 1) as encoded in the sector
ID field.
HLT
Head Load Time
The time interval that FDC waits after loading the head and before
initializing a read or write operation. Refer to the Specify
command for actual delays.
HUT
Head Unload
Time
The time interval from the end of the execution phase (of a read or
write command) until the head is unloaded. Refer to the Specify
command for actual delays.
LOCK
Lock defines whether EFIFO, FIFOTHR, and PRETRK parameters
of the CONFIGURE COMMAND can be reset to their default
values by a "software Reset". (A reset caused by writing to the
appropriate bits of either tha DSR or DOR)
MFM
MFM/FM Mode
Selector
A one selects the double density (MFM) mode. A zero selects
single density (FM) mode.
MT
Multi-Track
Selector
When set, this flag selects the multi-track operating mode. In this
mode, the FDC treats a complete cylinder under head 0 and 1 as
a single track. The FDC operates as this expanded track started
at the first sector under head 0 and ended at the last sector under
head 1. With this flag set, a multitrack read or write operation will
automatically continue to the first sector under head 1 when the
FDC finishes operating on the last sector under head 0.
N
Sector Size Code
This specifies the number of bytes in a sector. If this parameter is
"00", then the sector size is 128 bytes. The number of bytes
transferred is determined by the DTL parameter. Otherwise the
sector size is (2 raised to the "N'th" power) times 128. All values
up to "07" hex are allowable. "07"h would equal a sector size of
16k. It is the user's responsibility to not select combinations that
are not possible with the drive.
N
SECTOR SIZE
00
01
02
03
..
07
37
128 bytes
256 bytes
512 bytes
1024 bytes
...
16 Kbytes
Table 17 - Description of Command Symbols
SYMBOL
NAME
DESCRIPTION
NCN
New Cylinder
Number
The desired cylinder number.
ND
Non-DMA Mode
Flag
When set to 1, indicates that the FDC is to operate in the nonDMA mode. In this mode, the host is interrupted for each data
transfer. When set to 0, the FDC operates in DMA mode,
interfacing to a DMA controller by means of the DRQ and nDACK
signals.
OW
Overwrite
The bits D0-D3 of the Perpendicular Mode Command can only be
modified if OW is set to 1. OW id defined in the Lock command.
PCN
Present Cylinder
Number
The current position of the head at the completion of Sense
Interrupt Status command.
POLL
Polling Disable
When set, the internal polling routine is disabled. When clear,
polling is enabled.
PRETRK
Precompensation
Start Track
Number
Programmable from track 00 to FFH.
R
Sector Address
The sector number to be read or written. In multi-sector transfers,
this parameter specifies the sector number of the first sector to be
read or written.
RCN
Relative Cylinder
Number
Relative cylinder offset from present cylinder as used by the
Relative Seek command.
SC
Number of
The number of sectors per track to be initialized by the Format
Sectors Per Track command. The number of sectors per track to be verified during a
Verify command when EC is set.
SK
Skip Flag
SRT
Step Rate Interval The time interval between step pulses issued by the FDC.
Programmable from 0.5 to 8 milliseconds in increments of 0.5 ms
at the 1 Mbit data rate. Refer to the SPECIFY command for actual
delays.
ST0
ST1
ST2
ST3
Status 0
Status 1
Status 2
Status 3
When set to 1, sectors containing a deleted data address mark will
automatically be skipped during the execution of Read Data. If
Read Deleted is executed, only sectors with a deleted address
mark will be accessed. When set to "0", the sector is read or
written the same as the read and write commands.
Registers within the FDC which store status information after a
command has been executed. This status information is available
to the host during the result phase after command execution.
38
Table 17 - Description of Command Symbols
SYMBOL
WGATE
NAME
Write Gate
DESCRIPTION
Alters timing of WE to allow for pre-erase loads in perpendicular
drives.
39
INSTRUCTION SET
Table 18 - Instruction Set
READ DATA
DATA BUS
PHASE
Command
R/W
D7
D6
D5
D4
D3
D2
D1
D0
W
MT
MFM
SK
0
0
1
1
0
W
0
0
0
0
0
W
C
W
H
W
R
W
N
W
EOT
W
GPL
W
DTL
Command Codes
HDS DS1 DS0
Sector ID information prior to
Command execution.
Execution
Result
REMARKS
Data transfer between the
FDD and system.
R
ST0
R
ST1
R
ST2
R
C
R
H
R
R
R
N
Status information after
Command execution.
Sector ID information after
Command execution.
40
READ DELETED DATA
DATA BUS
PHASE
Command
R/W
D7
D6
D5
D4
D3
D2
D1
D0
W
MT
MFM
SK
0
1
1
0
0
W
0
0
0
0
0
W
C
W
H
W
R
W
N
W
EOT
W
GPL
W
DTL
Command Codes
HDS DS1 DS0
Sector ID information prior to
Command execution.
Execution
Result
REMARKS
Data transfer between the
FDD and system.
R
ST0
R
ST1
R
ST2
R
C
R
H
R
R
R
N
Status information after
Command execution.
Sector ID information after
Command execution.
41
WRITE DATA
DATA BUS
PHASE
Command
R/W
D7
D6
D5
D4
D3
D2
D1
D0
W
MT
MFM
0
0
0
1
0
1
W
0
0
0
0
0
W
C
W
H
W
R
W
N
W
EOT
W
GPL
W
DTL
Command Codes
HDS DS1 DS0
Sector ID information prior to
Command execution.
Execution
Result
REMARKS
Data transfer between the
FDD and system.
R
ST0
R
ST1
R
ST2
R
C
R
H
R
R
R
N
Status information after
Command execution.
Sector ID information after
Command execution.
42
WRITE DELETED DATA
DATA BUS
PHASE
Command
R/W
D7
D6
D5
D4
D3
D2
D1
D0
W
MT
MFM
0
0
1
0
0
1
W
0
0
0
0
0
HDS
DS1
DS0
W
C
W
H
W
R
W
N
W
EOT
W
GPL
W
DTL
Execution
Result
REMARKS
Command Codes
Sector ID information
prior to Command
execution.
Data transfer between
the FDD and system.
R
ST0
R
ST1
R
ST2
R
C
R
H
R
R
R
N
43
Status information after
Command execution.
Sector ID information
after Command
execution.
READ A TRACK
DATA BUS
PHASE
Command
R/W
D7
D6
D5
D4
D3
D2
D1
D0
W
0
MFM
0
0
0
0
1
0
W
0
0
0
0
0
HDS
DS1
DS0
W
C
W
H
W
R
W
N
W
EOT
W
GPL
W
DTL
Execution
Result
REMARKS
Command Codes
Sector ID information
prior to Command
execution.
Data transfer between
the FDD and system.
FDC reads all of
cylinders' contents from
index hole to EOT.
R
ST0
R
ST1
R
ST2
R
C
R
H
R
R
R
N
44
Status information after
Command execution.
Sector ID information
after Command
execution.
VERIFY
DATA BUS
PHASE
Command
R/W
D7
D6
D5
D4
D3
W
MT
MFM
SK
1
0
1
1
0
W
EC
0
0
0
0
HDS
DS1
DS0
W
C
W
H
W
R
W
N
W
EOT
W
GPL
W
DTL/SC
D2
D1
D0
Command Codes
Sector ID information
prior to Command
execution.
Execution
Result
REMARKS
No data transfer takes
place.
R
ST0
R
ST1
R
ST2
R
C
R
H
R
R
R
N
Status information after
Command execution.
Sector ID information
after Command
execution.
VERSION
DATA BUS
PHASE
R/W
D7
D6
D5
D4
D3
D2
D1
D0
Command
W
0
0
0
1
0
0
0
0
Command Code
Result
R
1
0
0
1
0
0
0
0
Enhanced Controller
45
REMARKS
FORMAT A TRACK
DATA BUS
PHASE
Command
Execution for
Each Sector
Repeat:
R/W
D7
D6
D5
D4
D3
D2
D1
D0
W
0
MFM
0
0
1
1
0
1
W
0
0
0
0
0
HDS
DS1
DS0
REMARKS
Command Codes
W
N
Bytes/Sector
W
SC
W
GPL
W
D
Filler Byte
W
C
Input Sector
Parameters
W
H
W
R
W
N
Sectors/Cylinder
Gap 3
FDC formats an entire
cylinder
Result
R
ST0
R
ST1
R
ST2
R
Undefined
R
Undefined
R
Undefined
R
Undefined
46
Status information after
Command execution
RECALIBRATE
DATA BUS
PHASE
Command
R/W
D7
D6
D5
D4
D3
D2
D1
D0
W
0
0
0
0
0
1
1
1
W
0
0
0
0
0
0
DS1
DS0
Execution
REMARKS
Command Codes
Head retracted to Track 0
Interrupt.
SENSE INTERRUPT STATUS
DATA BUS
PHASE
R/W
D7
D6
D5
D4
D3
D2
D1
D0
Command
W
0
0
0
0
1
0
0
0
Result
R
ST0
R
PCN
REMARKS
Command Codes
Status information at the end
of each seek operation.
SPECIFY
DATA BUS
PHASE
Command
R/W
D7
D6
D5
D4
D3
D2
D1
D0
W
0
0
0
0
0
0
1
1
W
W
SRT
HUT
HLT
ND
47
REMARKS
Command Codes
SENSE DRIVE STATUS
DATA BUS
PHASE
Command
Result
R/W
D7
D6
D5
D4
D3
D2
D1
D0
W
0
0
0
0
0
1
0
0
W
0
0
0
0
0
HDS
DS1
DS0
R
ST3
REMARKS
Command Codes
Status information about
FDD
SEEK
DATA BUS
PHASE
Command
R/W
D7
D6
D5
D4
D3
D2
D1
D0
W
0
0
0
0
1
1
1
1
W
0
0
0
0
0
HDS
DS1
DS0
W
REMARKS
Command Codes
NCN
Execution
Head positioned over
proper cylinder on
diskette.
CONFIGURE
DATA BUS
PHASE
Command
Execution
R/W
D7
D6
D5
D4
D3
D2
D1
D0
W
0
0
0
1
0
0
1
1
W
0
0
0
0
0
0
0
0
W
0
W
EIS EFIFO
POLL
PRETRK
48
FIFOTHR
REMARKS
Configure
Information
RELATIVE SEEK
DATA BUS
PHASE
Command
R/W
D7
D6
D5
D4
D3
D2
D1
D0
W
1
DIR
0
0
1
1
1
1
W
0
0
0
0
0
HDS
DS1
DS0
W
REMARKS
RCN
DUMPREG
DATA BUS
PHASE
Command
R/W
D7
D6
D5
D4
D3
D2
D1
D0
W
0
0
0
0
1
1
1
0
Execution
Result
R
PCN-Drive 0
R
PCN-Drive 1
R
PCN-Drive 2
R
PCN-Drive 3
R
SRT
R
HLT
R
ND
SC/EOT
R
LOCK
R
0
R
HUT
0
D3
EIS EFIFO
D2
D1
POLL
PRETRK
49
D0
GAP
FIFOTHR
WGATE
REMARKS
*Note:
Registers
placed in
FIFO
READ ID
DATA BUS
PHASE
Command
R/W
D7
D6
D5
D4
D3
D2
D1
D0
W
0
MFM
0
0
1
0
1
0
W
0
0
0
0
0
HDS
DS1
DS0
Execution
Result
REMARKS
Commands
The first correct ID
information on the
Cylinder is stored in
Data Register
R
ST0
Status information after
Command execution.
Disk status after the
Command has
completed
R
ST1
R
ST2
R
C
R
H
R
R
R
N
50
PERPENDICULAR MODE
DATA BUS
PHASE
Command
R/W
D7
D6
D5
D4
D3
D2
D1
D0
REMARKS
W
0
0
0
1
0
0
1
0
OW
0
D3
D2
D1
D0
GAP
WGATE
Command Codes
INVALID CODES
DATA BUS
PHASE
R/W
D7
D6
D5
D4
D3
Command
W
Invalid Codes
Result
R
ST0
D2
D1
REMARKS
D0
Invalid Command Codes
(NoOp - FDC goes into
Standby State)
ST0 = 80H
LOCK
DATA BUS
PHASE
R/W
D7
D6
D5
Command
W
LOCK
0
0
1
0
1
0
0
Result
R
0
0
0
LOCK
0
0
0
0
D4
D3
D2
D1
D0
REMARKS
Command Codes
SC is returned if the last command that was issued was the Format command. EOT is returned if the
last command was a Read or Write.
Note: These bits are used internally only. They are not reflected in the Drive Select pins. It is the
user's responsibility to maintain correspondence between these bits and the Drive Select pins (DOR).
51
N determines the number of bytes per sector
(see Table 21 below). If N is set to zero, the
sector size is set to 128. The DTL value
determines the number of bytes to be
transferred. If DTL is less than 128, the FDC
transfers the specified number of bytes to the
host. For reads, it continues to read the entire
128-byte sector and checks for CRC errors. For
writes, it completes the 128-byte sector by filling
in zeros. If N is not set to 00 Hex, DTL should
be set to FF Hex and has no impact on the
number of bytes transferred.
DATA TRANSFER COMMANDS
All of the Read Data, Write Data and Verify type
commands use the same parameter bytes and
return the same results information, the only
difference being the coding of bits 0-4 in the first
byte.
An implied seek will be executed if the feature
was enabled by the Configure command. This
seek is completely transparent to the user. The
Drive Busy bit for the drive will go active in the
Main Status Register during the seek portion of
the command. If the seek portion fails, it is
reflected in the results status normally returned
for a Read/Write Data command. Status
Register 0 (ST0) would contain the error code
and C would contain the cylinder on which the
seek failed.
Table 19 - Sector Sizes
Read Data
A set of nine (9) bytes is required to place the
FDC in the Read Data Mode. After the Read
Data command has been issued, the FDC loads
the head (if it is in the unloaded state), waits the
specified head settling time (defined in the
Specify command), and begins reading ID
Address Marks and ID fields. When the sector
address read off the diskette matches with the
sector address specified in the command, the
FDC reads the sector's data field and transfers
the data to the FIFO.
N
SECTOR SIZE
00
01
02
03
..
07
128 bytes
256 bytes
512 bytes
1024 bytes
...
16 Kbytes
The amount of data which can be handled with
a single command to the FDC depends upon
MT (multi-track) and N (number of bytes/sector).
The Multi-Track function (MT) allows the FDC to
read data from both sides of the diskette. For a
particular cylinder, data will be transferred
starting at Sector 1, Side 0 and completing the
last sector of the same track at Side 1.
After completion of the read operation from the
current sector, the sector address is
incremented by one and the data from the next
logical sector is read and output via the FIFO.
This continuous read function is called "MultiSector Read Operation". Upon receipt of TC, or
an implied TC (FIFO overrun/underrun), the
FDC stops sending data but will continue to
read data from the current sector, check the
CRC bytes, and at the end of the sector,
terminate the Read Data Command.
If the host terminates a read or write operation
in the FDC, the ID information in the result
phase is dependent upon the state of the MT bit
and EOT byte. Refer to Table 20.
At the completion of the Read Data command,
the head is not unloaded until after the Head
Unload Time Interval (specified in the Specify
command) has elapsed. If the host issues
another command before the head unloads,
52
After reading the ID and Data Fields in each
sector, the FDC checks the CRC bytes. If a
CRC error occurs in the ID or data field, the
FDC sets the IC code in Status Register 0 to
"01" indicating abnormal termination, sets the
DE bit flag in Status Register 1 to "1", sets the
DD bit in Status Register 2 to "1" if CRC is
incorrect in the ID field, and terminates the Read
Data Command. Table 21 describes the effect
of the SK bit on the Read Data command
execution and results. Except where noted in
Table 21, the C or R value of the sector address
is automatically incremented (see Table 23).
then the head settling time may be saved
between subsequent reads.
If the FDC detects a pulse on the nINDEX pin
twice without finding the specified sector
(meaning that the diskette's index hole passes
through index detect logic in the drive twice), the
FDC sets the IC code in Status Register 0 to
"01" indicating abnormal termination, sets the
ND bit in Status Register 1 to "1" indicating a
sector not found, and terminates the Read Data
Command.
MT
0
1
0
1
0
1
SK BIT
VALUE
0
0
1
1
N
1
1
2
2
3
3
Table 20 - Effects of MT and N Bits
MAXIMUM TRANSFER
FINAL SECTOR READ
CAPACITY
FROM DISK
26 at side 0 or 1
256 x 26 = 6,656
26 at side 1
256 x 52 = 13,312
15 at side 0 or 1
512 x 15 = 7,680
15 at side 1
512 x 30 = 15,360
8 at side 0 or 1
1024 x 8 = 8,192
16 at side 1
1024 x 16 = 16,384
Table 21 - Skip Bit vs Read Data Command
DATA ADDRESS
MARK TYPE
RESULTS
ENCOUNTERED
SECTOR CM BIT OF
DESCRIPTION
READ?
ST2 SET?
OF RESULTS
Normal Data
Yes
No
Normal
termination.
Deleted Data
Yes
Yes
Address not
incremented.
Next sector not
searched for.
Normal Data
Yes
No
Normal
termination.
Deleted Data
No
Yes
Normal
termination.
Sector not read
("skipped").
53
Table 22 describes the effect of the SK bit on
the Read Deleted Data command execution and
results.
Read Deleted Data
This command is the same as the Read Data
command, only it operates on sectors that
contain a Deleted Data Address Mark at the
beginning of a Data Field.
SK BIT
VALUE
Except where noted in Table 22, the C or R
value of the sector address is automatically
incremented (see Table 23).
Table 22 - Skip Bit vs. Read Deleted Data Command
DATA ADDRESS
MARK TYPE
RESULTS
ENCOUNTERED
SECTOR CM BIT OF
DESCRIPTION
READ?
ST2 SET?
OF RESULTS
0
Normal Data
Yes
Yes
0
Deleted Data
Yes
No
1
Normal Data
No
Yes
1
Deleted Data
Yes
No
Address not
incremented.
Next sector not
searched for.
Normal
termination.
Normal
termination.
Sector not read
("skipped").
Normal
termination.
the ND flag of Status Register 1 to a "1" if there
is no comparison. Multi-track or skip operations
are not allowed with this command. The MT and
SK bits (bits D7 and D5 of the first command
byte respectively) should always be set to "0".
Read A Track
This command is similar to the Read Data
command except that the entire data field is
read continuously from each of the sectors of a
track. Immediately after encountering a pulse
on the nINDEX pin, the FDC starts to read all
data fields on the track as continuous blocks of
data without regard to logical sector numbers. If
the FDC finds an error in the ID or DATA CRC
check bytes, it continues to read data from the
track and sets the appropriate error bits at the
end of the command. The FDC compares the
ID information read from each sector with the
specified value in the command and sets
This command terminates when the EOT
specified number of sectors has not been read.
If the FDC does not find an ID Address Mark on
the diskette after the second occurrence of a
pulse on the IDX pin, then it sets the IC code in
Status Register 0 to "01" (abnormal
termination), sets the MA bit in Status Register
1 to "1", and terminates the command.
54
Table 23 - Result Phase Table
MT
0
1
HEAD
FINAL SECTOR
TRANSFERRED TO
HOST
ID INFORMATION AT RESULT PHASE
C
H
R
N
Less than EOT
NC
NC
R+1
NC
Equal to EOT
C+1
NC
01
NC
1
Less than EOT
NC
NC
R+1
NC
Equal to EOT
C+1
NC
01
NC
0
Less than EOT
NC
NC
R+1
NC
Equal to EOT
NC
LSB
01
NC
1
Less than EOT
NC
NC
R+1
NC
Equal to EOT
C+1
LSB
01
NC
0
NC: No Change, the same value as the one at the beginning of command execution.
LSB: Least Significant Bit, the LSB of H is complemented.
termination), sets the DE bit of Status Register 1
to "1", and terminates the Write Data command.
Write Data
The Write Data command operates in much the
same manner as the Read Data command. The
following items are the same. Please refer to the
Read Data Command for details:
After the Write Data command has been issued,
the FDC loads the head (if it is in the unloaded
state), waits the specified head load time if
unloaded (defined in the Specify command),
and begins reading ID fields. When the sector
address read from the diskette matches the
sector address specified in the command, the
FDC reads the data from the host via the FIFO
and writes it to the sector's data field.
•
•
•
•
•
After writing data into the current sector, the
FDC computes the CRC value and writes it into
the CRC field at the end of the sector transfer.
The Sector Number stored in "R" is incremented
by one, and the FDC continues writing to the
next data field. The FDC continues this "MultiSector Write Operation". Upon receipt of a
terminal count signal or if a FIFO over/under run
occurs while a data field is being written, then
the remainder of the data field is filled with
zeros.
The FDC reads the ID field of each
sector and checks the CRC bytes. If it detects a
CRC error in one of the ID fields, it sets the IC
code in Status Register 0 to "01" (abnormal
•
Transfer Capacity
EN (End of Cylinder) bit
ND (No Data) bit
Head Load, Unload Time Interval
ID information when the host terminates the
command
Definition of DTL when N = 0 and when N
does not = 0
Write Deleted Data
This command is almost the same as the Write
Data command except that a Deleted Data
Address Mark is written at the beginning of the
Data Field instead of the normal Data Address
Mark. This command is typically used to mark
a bad sector containing an error on the floppy
disk.
55
verify 256 sectors). This command can also be
terminated by setting the EC bit to "0" and the
EOT value equal to the final sector to be
checked. If EC is set to "0", DTL/SC should be
programmed to 0FFH. Refer to Table 23 and
Table 24 for information concerning the values
of MT and EC versus SC and EOT value.
Verify
The Verify command is used to verify the data
stored on a disk. This command acts exactly
like a Read Data command except that no data
is transferred to the host. Data is read from the
disk and CRC is computed and checked against
the previously-stored value.
Definitions:
Because data is not transferred to the host, TC
(pin 89) cannot be used to terminate this
command. By setting the EC bit to "1", an
implicit TC will be issued to the FDC. This
implicit TC will occur when the SC value has
decremented to 0 (an SC value of 0 will
# Sectors Per Side = Number of formatted
sectors per each side of the disk.
# Sectors Remaining = Number of formatted
sectors left which can be read, including side 1
of the disk if MT is set to "1".
Table 24 - Verify Command Result Phase Table
SC/EOT VALUE
TERMINATION RESULT
MT
EC
0
0
SC = DTL
EOT ≤ # Sectors Per Side
Success Termination
Result Phase Valid
0
0
SC = DTL
EOT > # Sectors Per Side
Unsuccessful Termination
Result Phase Invalid
0
1
SC ≤ # Sectors Remaining AND
EOT ≤ # Sectors Per Side
Successful Termination
Result Phase Valid
0
1
SC > # Sectors Remaining OR
EOT > # Sectors Per Side
Unsuccessful Termination
Result Phase Invalid
1
0
SC = DTL
EOT ≤ # Sectors Per Side
Successful Termination
Result Phase Valid
1
0
SC = DTL
EOT > # Sectors Per Side
Unsuccessful Termination
Result Phase Invalid
1
1
SC ≤ # Sectors Remaining AND
EOT ≤ # Sectors Per Side
Successful Termination
Result Phase Valid
1
1
SC > # Sectors Remaining OR
EOT > # Sectors Per Side
Unsuccessful Termination
Result Phase Invalid
Note: If MT is set to "1" and the SC value is greater than the number of remaining formatted sectors
on Side 0, verifying will continue on Side 1 of the disk.
56
After formatting each sector, the host must send
new values for C, H, R and N to the FDC for the
next sector on the track. The R value (sector
number) is the only value that must be changed
by the host after each sector is formatted. This
allows the disk to be formatted with
nonsequential sector addresses (interleaving).
This incrementing and formatting continues for
the whole track until the FDC encounters a pulse
on the IDX pin again and it terminates the
command.
Format A Track
The Format command allows an entire track to
be formatted. After a pulse from the IDX pin is
detected, the FDC starts writing data on the disk
including gaps, address marks, ID fields, and
data fields per the IBM System 34 or 3740
format (MFM or FM respectively). The particular
values that will be written to the gap and data
field are controlled by the values programmed
into N, SC, GPL, and D which are specified by
the host during the command phase. The data
field of the sector is filled with the data byte
specified by D. The ID field for each sector is
supplied by the host; that is, four data bytes per
sector are needed by the FDC for C, H, R, and
N (cylinder, head, sector number and sector size
respectively).
Table 25 contains typical values for gap fields
which are dependent upon the size of the sector
and the number of sectors on each track. Actual
values can vary due to drive electronics.
FORMAT FIELDS
SYSTEM 34 (DOUBLE DENSITY) FORMAT
GAP4a
80x
4E
SYNC
12x
00
IAM
GAP1 SYNC
50x
12x
4E
00
3x FC
C2
IDAM
C
Y
L
H
D
S
E
C
N
O
C
R
C
GAP2 SYNC
22x
12x
4E
00
3x FE
A1
DATA
AM
DATA
C
R
C
GAP3 GAP 4b
DATA
C
R
C
GAP3 GAP 4b
DATA
C
R
C
GAP3 GAP 4b
3x FB
A1 F8
SYSTEM 3740 (SINGLE DENSITY) FORMAT
GAP4a
40x
FF
SYNC
6x
00
IAM
GAP1 SYNC
26x
6x
FF
00
FC
IDAM
C
Y
L
H
D
S
E
C
N
O
C
R
C
GAP2 SYNC
11x
6x
FF
00
FE
DATA
AM
FB or
F8
PERPENDICULAR FORMAT
GAP4a
80x
4E
SYNC
12x
00
IAM
3x FC
C2
GAP1 SYNC
50x
12x
4E
00
IDAM
C
Y
L
H
D
S
E
C
3x FE
A1
N
O
C
R
C
GAP2 SYNC
41x
12x
4E
00
DATA
AM
3x FB
A1 F8
57
FORMAT
GPL2
FM
128
128
512
1024
2048
4096
...
00
00
02
03
04
05
...
12
10
08
04
02
01
07
10
18
46
C8
C8
09
19
30
87
FF
FF
MFM
256
256
512*
1024
2048
4096
...
01
01
02
03
04
05
...
12
10
09
04
02
01
0A
20
2A
80
C8
C8
0C
32
50
F0
FF
FF
FM
128
256
512
0
1
2
0F
09
05
07
0F
1B
1B
2A
3A
MFM
256
512**
1024
1
2
3
0F
09
05
0E
1B
35
36
54
74
5.25"
Drives
3.5"
Drives
Table 25 - Typical Values for Formatting
SECTOR SIZE
N
SC
GPL1
GPL1 = suggested GPL values in Read and Write commands to avoid splice point
between data field and ID field of contiguous sections.
GPL2 = suggested GPL value in Format A Track command.
*PC/AT values (typical)
**PS/2 values (typical). Applies with 1.0 MB and 2.0 MB drives.
NOTE: All values except sector size are in hex.
58
The Recalibrate command does not have a
result phase.
The Sense Interrupt Status
command must be issued after the Recalibrate
command to effectively terminate it and to
provide verification of the head position (PCN).
During the command phase of the recalibrate
operation, the FDC is in the BUSY state, but
during the execution phase it is in a NON-BUSY
state.
At this time, another Recalibrate
command may be issued, and in this manner
parallel Recalibrate operations may be done on
up to four drives at once.
CONTROL COMMANDS
Control commands differ from the other
commands in that no data transfer takes place.
Three commands generate an interrupt when
complete: Read ID, Recalibrate, and Seek. The
other control commands do not generate an
interrupt.
Read ID
The Read ID command is used to find the
present position of the recording heads. The
FDC stores the values from the first ID field it is
able to read into its registers. If the FDC does
not find an ID address mark on the diskette after
the second occurrence of a pulse on the
nINDEX pin, it then sets the IC code in Status
Register 0 to "01" (abnormal termination), sets
the MA bit in Status Register 1 to "1", and
terminates the command.
Upon power up, the software must issue a
Recalibrate command to properly initialize all
drives and the controller.
Seek
The read/write head within the drive is moved
from track to track under the control of the Seek
command. The FDC compares the PCN, which
is the current head position, with the NCN and
performs the following operation if there is a
difference:
The following commands will generate an
interrupt upon completion. They do not return
any result bytes. It is highly recommended that
control commands be followed by the Sense
Interrupt Status command. Otherwise, valuable
interrupt status information will be lost.
PCN < NCN: Direction signal to drive set to
"1" (step in) and issues step pulses.
PCN > NCN: Direction signal to drive set to
"0" (step out) and issues step pulses.
Recalibrate
The rate at which step pulses are issued is
controlled by SRT (Stepping Rate Time) in the
Specify command. After each step pulse is
issued, NCN is compared against PCN, and
when NCN = PCN the SE bit in Status Register
0 is set to "1" and the command is terminated.
During the command phase of the seek or
recalibrate operation, the FDC is in the BUSY
state, but during the execution phase it is in the
NON-BUSY state. At this time, another Seek or
Recalibrate command may be issued, and in
this manner, parallel seek operations may be
done on up to four drives at once.
This command causes the read/write head
within the FDC to retract to the track 0 position.
The FDC clears the contents of the PCN counter
and checks the status of the nTR0 pin from the
FDD. As long as the nTR0 pin is low, the DIR
pin remains 0 and step pulses are issued. When
the nTR0 pin goes high, the SE bit in Status
Register 0 is set to "1" and the command is
terminated. If the nTR0 pin is still low after 79
step pulses have been issued, the FDC sets the
SE and the EC bits of Status Register 0 to "1"
and terminates the command. Disks capable of
handling more than 80 tracks per side may
require more than one Recalibrate command to
return the head back to physical Track 0.
59
g. Write Deleted Data command
h. Verify command
Note that if implied seek is not enabled, the read
and write commands should be preceded by:
1) Seek command - Step to the proper track
2) Sense Interrupt Status command
Terminate the Seek command
3) Read ID - Verify head is on proper track
4) Issue Read/Write command.
2. End of Seek, Relative Seek, or Recalibrate
command
-
3. FDC requires a data transfer during the
execution phase in the non-DMA mode
The Sense Interrupt Status command resets the
interrupt signal and, via the IC code and SE bit
of Status Register 0, identifies the cause of the
interrupt.
The Seek command does not have a result
phase. Therefore, it is highly recommended that
the Sense Interrupt Status command is issued
after the Seek command to terminate it and to
provide verification of the head position (PCN).
The H bit (Head Address) in ST0 will always
return to a "0". When exiting POWERDOWN
mode, the FDC clears the PCN value and the
status information to zero. Prior to issuing the
POWERDOWN command, it is highly
recommended that the user service all pending
interrupts through the Sense Interrupt Status
command.
Table 26 - Interrupt Identification
SE
IC
INTERRUPT DUE TO
0
1
11
00
1
01
Polling
Normal termination of Seek
or Recalibrate command
Abnormal termination of
Seek or Recalibrate
command
Sense Interrupt Status
The Seek, Relative Seek, and Recalibrate
commands have no result phase. The Sense
Interrupt Status command must be issued
immediately after these commands to terminate
them and to provide verification of the head
position (PCN). The H (Head Address) bit in
ST0 will always return a "0". If a Sense Interrupt
Status is not issued, the drive will continue to be
BUSY and may affect the operation of the next
command.
An interrupt signal on FINT pin is generated by
the FDC for one of the following reasons:
1. Upon entering the Result Phase of:
a. Read Data command
b. Read A Track command
c. Read ID command
d. Read Deleted Data command
e. Write Data command
f. Format A Track command
60
from the end of the execution phase of one of
the read/write commands to the head unload
state. The SRT (Step Rate Time) defines the
time interval between adjacent step pulses. Note
that the spacing between the first and second
step pulses may be shorter than the remaining
step pulses.
The HLT (Head Load Time)
defines the time between when the Head Load
signal goes high and the read/write operation
starts. The values change with the data rate
speed selection and are documented in Table
27. The values are the same for MFM and FM.
Sense Drive Status
Sense Drive Status obtains drive status
information. It has not execution phase and
goes directly to the result phase from the
command phase. Status Register 3 contains
the drive status information.
Specify
The Specify command sets the initial values for
each of the three internal times. The HUT
(Head Unload Time) defines the time
Table 27 - Drive Control Delays (ms)
HUT
0
1
..
E
F
SRT
2M
1M
500K
300K
250K
2M
1M
500K
300K
250K
64
4
..
56
60
128
8
..
112
120
256
16
..
224
240
426
26.7
..
373
400
512
32
..
448
480
4
3.75
..
0.5
0.25
8
7.5
..
1
0.5
16
15
..
2
1
26.7
25
..
3.33
1.67
32
30
..
4
2
HLT
00
01
02
..
7F
7F
2M
1M
500K
300K
250K
64
0.5
1
..
63
63.5
128
1
2
..
126
127
256
2
4
..
252
254
426
3.3
6.7
..
420
423
512
4
8
.
504
508
The choice of DMA or non-DMA operations is
made by the ND bit. When this bit is "1", the
non-DMA mode is selected, and when ND is "0",
the DMA mode is selected. In DMA mode, data
transfers are signaled by the FDRQ pin. NonDMA mode uses the RQM bit and the FINT pin
to signal data transfers.
Configure
The Configure command is issued to select the
special features of the FDC.
A Configure
command need not be issued if the default
values of the FDC meet the system
requirements.
61
Configure Default Values:
Relative Seek
EIS - No Implied Seeks
EFIFO - FIFO Disabled
POLL - Polling Enabled
FIFOTHR - FIFO Threshold Set to 1 Byte
PRETRK - Pre-Compensation Set to Track 0
The command is coded the same as for Seek,
except for the MSB of the first byte and the DIR
bit.
DIR
EIS - Enable Implied Seek. When set to "1", the
FDC will perform a Seek operation before
executing a read or write command. Defaults to
no implied seek.
Head Step Direction Control
DIR
0
1
EFIFO - A "1" disables the FIFO (default). This
means data transfers are asked for on a byteby-byte basis. Defaults to "1", FIFO disabled.
The threshold defaults to "1".
RCN
POLL - Disable polling of the drives. Defaults to
"0", polling enabled. When enabled, a single
interrupt is generated after a reset. No polling is
performed while the drive head is loaded and
the head unload delay has not expired.
ACTION
Step Head Out
Step Head In
Relative
Cylinder
Number
that
determines how many tracks to step the
head in or out from the current track
number.
The Relative Seek command differs from the
Seek command in that it steps the head the
absolute number of tracks specified in the
command instead of making a comparison
against an internal register.
The Seek
command is good for drives that support a
maximum of 256 tracks. Relative Seeks cannot
be overlapped with other Relative Seeks. Only
one Relative Seek can be active at a time.
Relative Seeks may be overlapped with Seeks
and Recalibrates. Bit 4 of Status Register 0
(EC) will be set if Relative Seek attempts to step
outward beyond Track 0.
FIFOTHR - The FIFO threshold in the execution
phase of read or write commands. This is
programmable from 1 to 16 bytes. Defaults to
one byte. A "00" selects one byte; "0F" selects
16 bytes.
PRETRK - Pre-Compensation Start Track
Number. Programmable from track 0 to 255.
Defaults to track 0. A "00" selects track 0; "FF"
selects track 255.
As an example, assume that a floppy drive has
300 useable tracks. The host needs to read
track 300 and the head is on any track (0-255).
If a Seek command is issued, the head will stop
at track 255. If a Relative Seek command is
issued, the FDC will move the head the
specified number of tracks, regardless of the
internal cylinder position register (but will
increment the register). If the head was on track
40 (d), the maximum track that the FDC could
position the head on using Relative Seek will be
295 (D), the initial track + 255 (D). The
maximum count that the head can be moved
Version
The Version command checks to see if the
controller is an enhanced type or the older type
(765A). A value of 90 H is returned as the result
byte.
62
with a single Relative Seek command is 255
(D).
Perpendicular Mode
The Perpendicular Mode command should be
issued prior to executing Read/Write/Format
commands that access a disk drive with
perpendicular recording capability. With this
command, the length of the Gap2 field and VCO
enable timing can be altered to accommodate
the unique requirements of these drives. Table
28 describes the effects of the WGATE and
GAP bits for the Perpendicular Mode command.
Upon a reset, the FDC will default to the
conventional mode (WGATE = 0, GAP = 0).
The internal register, PCN, will overflow as the
cylinder number crosses track 255 and will
contain 39 (D). The resulting PCN value is thus
(RCN + PCN) mod 256. Functionally, the FDC
starts counting from 0 again as the track
number goes above 255 (D). It is the user's
responsibility to compensate FDC functions
(precompensation
track
number)
when
accessing tracks greater than 255. The FDC
does not keep track that it is working in an
"extended track area" (greater than 255). Any
command issued will use the current PCN value
except for the Recalibrate command, which only
looks for the TRACK0 signal. Recalibrate will
return an error if the head is farther than 79 due
to its limitation of issuing a maximum of 80 step
pulses. The user simply needs to issue a second
Recalibrate command. The Seek command and
implied seeks will function correctly within the
44 (D) track (299-255) area of the "extended
track area". It is the user's responsibility not to
issue a new track position that will exceed the
maximum track that is present in the extended
area.
Selection of the 500 Kbps and 1 Mbps
perpendicular modes is independent of the
actual data rate selected in the Data Rate Select
Register. The user must ensure that these two
data rates remain consistent.
The Gap2 and VCO timing requirements for
perpendicular recording type drives are dictated
by the design of the read/write head. In the
design of this head, a pre-erase head precedes
the normal read/write head by a distance of 200
micrometers. This works out to about 38 bytes
at a 1 Mbps recording density. Whenever the
write head is enabled by the Write Gate signal,
the pre-erase head is also activated at the same
time. Thus, when the write head is initially
turned on, flux transitions recorded on the media
for the first 38 bytes will not be preconditioned
with the pre-erase head since it has not yet been
activated. To accommodate this head activation
and deactivation time, the Gap2 field is
expanded to a length of 41 bytes. The format
field shown on Page 58 illustrates the change in
the Gap2 field size for the perpendicular format.
To return to the standard floppy range (0-255) of
tracks, a Relative Seek should be issued to
cross the track 255 boundary.
A Relative Seek can be used instead of the
normal Seek, but the host is required to
calculate the difference between the current
head location and the new (target) head
location. This may require the host to issue a
Read ID command to ensure that the head is
physically on the track that software assumes it
to be. Different FDC commands will return
different cylinder results which may be difficult
to keep track of with software without the Read
ID command.
63
The perpendicular mode command is enhanced
to allow specific drives to be designated
Perpendicular
recording
drives.
This
enhancement allows data transfers between
Conventional and Perpendicular drives without
having to issue Perpendicular mode commands
between the accesses of the different drive
types, nor having to change write precompensation values.
On the read back by the FDC, the controller
must begin synchronization at the beginning of
the sync field. For the conventional mode, the
internal PLL VCO is enabled (VCOEN)
approximately 24 bytes from the start of the
Gap2 field. But, when the controller operates in
the 1 Mbps perpendicular mode (WGATE = 1,
GAP = 1), VCOEN goes active after 43 bytes to
accommodate the increased Gap2 field size.
For both cases, and approximate two-byte
cushion is maintained from the beginning of the
sync field for the purposes of avoiding write
splices in the presence of motor speed variation.
When both GAP and WGATE bits of the
PERPENDICULAR MODE COMMAND are both
programmed to "0" (Conventional mode), then
D0, D1, D2, D3, and D4 can be programmed
independently to "1" for that drive to be set
automatically to Perpendicular mode. In this
mode the following set of conditions also apply:
1. The GAP2 written to a perpendicular drive
during a write operation will depend upon the
programmed data rate.
2. The write pre-compensation given to a
perpendicular mode drive will be 0ns.
3. For D0-D3 programmed to "0" for
conventional mode drives any data written
will be at the currently programmed write
pre-compensation.
For the Write Data case, the FDC activates
Write Gate at the beginning of the sync field
under the conventional mode. The controller
then writes a new sync field, data address mark,
data field, and CRC as shown on page 57. With
the pre-erase head of the perpendicular drive,
the write head must be activated in the Gap2
field to insure a proper write of the new sync
field. For the 1 Mbps perpendicular mode
(WGATE = 1, GAP = 1), 38 bytes will be written
in the Gap2 space. Since the bit density is
proportional to the data rate, 19 bytes will be
written in the Gap2 field for the 500 Kbps
perpendicular mode (WGATE = 1, GAP =0).
Note: Bits D0-D3 can only be overwritten when
OW is programmed as a "1".If either
GAP or WGATE is a "1" then D0-D3 are
ignored.
It should be noted that none of the alterations in
Gap2 size, VCO timing, or Write Gate timing
affect normal program flow. The information
provided here is just for background purposes
and is not needed for normal operation. Once
the Perpendicular Mode command is invoked,
FDC software behavior from the user standpoint
is unchanged.
Software and hardware resets have the
following effect on the PERPENDICULAR
MODE COMMAND:
1. "Software" resets (via the DOR or DSR
registers) will only clear GAP and WGATE
bits to "0". D0-D3 are unaffected and retain
their previous value.
2. "Hardware" resets will clear all bits
(GAP, WGATE and D0-D3) to "0", i.e all
conventional mode.
64
WGATE
Table 28 - Effects of WGATE and GAP Bits
PORTION OF
GAP 2
WRITTEN BY
LENGTH OF
GAP2 FORMAT WRITE DATA
OPERATION
FIELD
GAP
MODE
0
0
0
1
1
0
1
1
Conventional
Perpendicular
(500 Kbps)
Reserved
(Conventional)
Perpendicular
(1 Mbps)
22 Bytes
22 Bytes
0 Bytes
19 Bytes
22 Bytes
0 Bytes
41 Bytes
38 Bytes
LOCK
ENHANCED DUMPREG
In order to protect systems with long DMA
latencies against older application software that
can disable the FIFO the LOCK Command has
been added. This command should only be
used by the FDC routines, and application
software should refrain from using it. If an
application calls for the FIFO to be disabled
then the CONFIGURE command should be
used.
The DUMPREG command is designed to
support system run-time diagnostics and
application software development and debug.
To accommodate the LOCK command and the
enhanced PERPENDICULAR MODE command
the eighth byte of the DUMPREG command has
been modified to contain the additional data
from these two commands.
COMPATIBILITY
The LOCK command defines whether the
EFIFO, FIFOTHR, and PRETRK parameters of
the CONFIGURE command can be RESET by
the DOR and DSR registers. When the LOCK
bit is set to logic "1" all subsequent "software
RESETS by the DOR and DSR registers will not
change the previously set parameters to their
default values. All "hardware" RESET from the
RESET pin will set the LOCK bit to logic "0" and
return the EFIFO, FIFOTHR, and PRETRK to
their default values. A status byte is returned
immediately after issuing a LOCK command.
This byte reflects the value of the LOCK bit set
by the command byte.
The FDC37B77x was designed with software
compatibility in mind. It is a fully backwardscompatible solution with the older generation
765A/B disk controllers. The FDC also
implements on-board registers for compatibility
with the PS/2, as well as PC/AT and PC/XT,
floppy disk controller subsystems. After a
hardware reset of the FDC, all registers,
functions and enhancements default to a PC/AT,
PS/2 or PS/2 Model 30 compatible operating
mode, depending on how the IDENT and MFM
bits are configured by the system BIOS.
65
SERIAL PORT (UART)
"1". OUT2 being a logic "0" disables that
UART's interrupt.
The second UART also
supports IrDA, HP-SIR, ASK-IR, Fast IR and
Consumer IR infrared modes of operation.
The FDC37B77x incorporates two full function
UARTs.
They are compatible with the
NS16450, the 16450 ACE registers and the
NS16C550A. The UARTS perform serial-toparallel conversion on received characters and
parallel-to-serial
conversion
on
transmit
characters. The data rates are independently
programmable from 460.8K baud down to 50
baud. The character options are programmable
for 1 start; 1, 1.5 or 2 stop bits; even, odd, sticky
or no parity; and prioritized interrupts. The
UARTs each contain a programmable baud rate
generator that is capable of dividing the input
clock or crystal by a number from 1 to 65535.
The UARTs are also capable of supporting the
MIDI data rate. Refer to the Configuration
Registers for information on disabling, power
down and changing the base address of the
UARTs. The interrupt from a UART is enabled
by programming OUT2 of that UART to a logic
Note: The UARTs may be configured to share
an interrupt. Refer to the Configuration section
for more information.
REGISTER DESCRIPTION
Addressing of the accessible registers of the
Serial Port is shown below.
The base
addresses of the serial ports are defined by the
configuration registers (see Configuration
section). The Serial Port registers are located at
sequentially increasing addresses above these
base addresses. The FDC37B77x contains two
serial ports, each of which contain a register set
as described below.
Table 29 - Addressing the Serial Port
A1
A0
REGISTER NAME
DLAB*
A2
0
0
0
0
Receive Buffer (read)
0
0
0
0
Transmit Buffer (write)
0
0
0
1
Interrupt Enable (read/write)
X
0
1
0
Interrupt Identification (read)
X
0
1
0
FIFO Control (write)
X
0
1
1
Line Control (read/write)
X
1
0
0
Modem Control (read/write)
X
1
0
1
Line Status (read/write)
X
1
1
0
Modem Status (read/write)
X
1
1
1
Scratchpad (read/write)
1
0
0
0
Divisor LSB (read/write)
1
0
0
1
Divisor MSB (read/write
*Note: DLAB is Bit 7 of the Line Control Register
66
The following section describes the operation of
the registers.
Bit 0
This bit enables the Received Data Available
Interrupt (and timeout interrupts in the FIFO
mode) when set to logic "1".
Bit 1
This bit enables the Transmitter Holding
Register Empty Interrupt when set to logic "1".
Bit 2
This bit enables the Received Line Status
Interrupt when set to logic "1". The error
sources causing the interrupt are Overrun,
Parity, Framing and Break. The Line Status
Register must be read to determine the source.
Bit 3
This bit enables the MODEM Status Interrupt
when set to logic "1". This is caused when one
of the Modem Status Register bits changes
state.
Bits 4 through 7
These bits are always logic "0".
RECEIVE BUFFER REGISTER (RB)
Address Offset = 0H, DLAB = 0, READ ONLY
This register holds the received incoming data
byte. Bit 0 is the least significant bit, which is
transmitted and received first. Received data is
double buffered; this uses an additional shift
register to receive the serial data stream and
convert it to a parallel 8 bit word which is
transferred to the Receive Buffer register. The
shift register is not accessible.
TRANSMIT BUFFER REGISTER (TB)
Address Offset = 0H, DLAB = 0, WRITE ONLY
This register contains the data byte to be
transmitted.
The transmit buffer is double
buffered, utilizing an additional shift register (not
accessible) to convert the 8 bit data word to a
serial format. This shift register is loaded from
the Transmit Buffer when the transmission of
the previous byte is complete.
FIFO CONTROL REGISTER (FCR)
Address Offset = 2H, DLAB = X, WRITE
This is a write only register at the same location
as the IIR. This register is used to enable and
clear the FIFOs, set the RCVR FIFO trigger
level. Note: DMA is not supported. The UART1
and UART2 FCR’s are shadowed in the UART1
FIFO Control Shadow Register (LD8:CRC3[7:0])
and UART2 FIFO Control Shadow Register
(LD8:CRC4[7:0]).
INTERRUPT ENABLE REGISTER (IER)
Address Offset = 1H, DLAB = 0, READ/WRITE
The lower four bits of this register control the
enables of the five interrupt sources of the Serial
Port interrupt. It is possible to totally disable the
interrupt system by resetting bits 0 through 3 of
this register. Similarly, setting the appropriate
bits of this register to a high, selected interrupts
can be enabled. Disabling the interrupt system
inhibits the Interrupt Identification Register and
disables any Serial Port interrupt out of the
FDC37B77x. All other system functions operate
in their normal manner, including the Line
Status and MODEM Status Registers. The
contents of the Interrupt Enable Register are
described below.
Bit 0
Setting this bit to a logic "1" enables both the
XMIT and RCVR FIFOs. Clearing this bit to a
logic "0" disables both the XMIT and RCVR
FIFOs and clears all bytes from both FIFOs.
When changing from FIFO Mode to non-FIFO
(16450) mode, data is automatically cleared
from the FIFOs. This bit must be a 1 when
other bits in this register are written to or they
will not be properly programmed.
67
3.
4.
Bit 1
Setting this bit to a logic "1" clears all bytes in
the RCVR FIFO and resets its counter logic to 0.
The shift register is not cleared. This bit is selfclearing.
Information indicating that a prioritized interrupt
is pending and the source of that interrupt is
stored in the Interrupt Identification Register
(refer to Interrupt Control Table). When the CPU
accesses the IIR, the Serial Port freezes all
interrupts and indicates the highest priority
pending interrupt to the CPU. During this CPU
access, even if the Serial Port records new
interrupts, the current indication does not
change until access is completed. The contents
of the IIR are described below.
Bit 2
Setting this bit to a logic "1" clears all bytes in
the XMIT FIFO and resets its counter logic to 0.
The shift register is not cleared. This bit is selfclearing.
Bit 3
Writing to this bit has no effect on the operation
of the UART. The RXRDY and TXRDY pins are
not available on this chip.
Bit 4,5
Reserved
Bit 6,7
These bits are used to set the trigger level for
the RCVR FIFO interrupt.
Bit 7
0
Bit 0
This bit can be used in either a hardwired
prioritized or polled environment to indicate
whether an interrupt is pending. When bit 0 is a
logic "0", an interrupt is pending and the
contents of the IIR may be used as a pointer to
the appropriate internal service routine. When
bit 0 is a logic "1", no interrupt is pending.
RCVR FIFO
Bit 6 Trigger Level (BYTES)
0
1
0
1
4
1
0
8
1
1
14
Bits 1 and 2
These two bits of the IIR are used to identify the
highest priority interrupt pending as indicated by
the Interrupt Control Table.
Bit 3
In non-FIFO mode, this bit is a logic "0". In
FIFO mode this bit is set along with bit 2 when a
timeout interrupt is pending.
INTERRUPT IDENTIFICATION REGISTER
(IIR)
Address Offset = 2H, DLAB = X, READ
Bits 4 and 5
These bits of the IIR are always logic "0".
By accessing this register, the host CPU can
determine the highest priority interrupt and its
source. Four levels of priority interrupt exist.
They are in descending order of priority:
1.
2.
Transmitter Holding Register Empty
MODEM Status (lowest priority)
Bits 6 and 7
These two bits are set when the FIFO
CONTROL Register bit 0 equals 1.
Receiver Line Status (highest priority)
Received Data Ready
68
Table 30 - Interrupt Control Table
FIFO
MODE
ONLY
BIT 3
0
INTERRUPT
IDENTIFICATION
REGISTER
BIT 2 BIT 1 BIT 0
0
0
1
INTERRUPT SET AND RESET FUNCTIONS
PRIORITY INTERRUPT
LEVEL
TYPE
None
INTERRUPT
SOURCE
None
INTERRUPT
RESET CONTROL
Reading the Line
Status Register
0
1
1
0
Highest
Receiver Line Overrun Error,
Status
Parity Error,
Framing Error or
Break Interrupt
0
1
0
0
Second
Received
Data
Available
Receiver Data
Available
Read Receiver
Buffer or the FIFO
drops below the
trigger level.
1
1
0
0
Second
Character
Timeout
Indication
No Characters
Have Been
Removed From
or Input to the
RCVR FIFO
during the last 4
Char times and
there is at least 1
char in it during
this time
Reading the
Receiver Buffer
Register
0
0
1
0
Third
Transmitter
Holding
Register
Empty
Transmitter
Holding Register
Empty
Reading the IIR
Register (if Source
of Interrupt) or
Writing the
Transmitter Holding
Register
0
0
0
0
Fourth
MODEM
Status
Clear to Send or
Data Set Ready
or Ring Indicator
or Data Carrier
Detect
Reading the
MODEM Status
Register
69
BIT 2
WORD LENGTH
NUMBER OF
STOP BITS
0
--
1
1
5 bits
1.5
1
6 bits
2
odd number of 1s when the data word bits and
the parity bit are summed).
Bit 4
Even Parity Select bit. When bit 3 is a logic "1"
and bit 4 is a logic "0", an odd number of logic
"1"'s is transmitted or checked in the data word
bits and the parity bit. When bit 3 is a logic "1"
and bit 4 is a logic "1" an even number of bits is
transmitted and checked.
Bit 5
Stick Parity bit. When bit 3 is a logic "1" and bit
5 is a logic "1", the parity bit is transmitted and
then detected by the receiver in the opposite
state indicated by bit 4.
Bit 6
Set Break Control bit. When bit 6 is a logic "1",
the transmit data output (TXD) is forced to the
Spacing or logic "0" state and remains there
(until reset by a low level bit 6) regardless of
other transmitter activity. This feature enables
the Serial Port to alert a terminal in a
communications system.
Bit 7
Divisor Latch Access bit (DLAB). It must be set
high (logic "1") to access the Divisor Latches of
the Baud Rate Generator during read or write
operations. It must be set low (logic "0") to
access the Receiver Buffer Register, the
Transmitter Holding Register, or the Interrupt
Enable Register.
1
7 bits
2
MODEM CONTROL REGISTER (MCR)
1
8 bits
2
Address Offset = 4H, DLAB = X, READ/WRITE
LINE CONTROL REGISTER (LCR)
Address Offset = 3H, DLAB = 0, READ/WRITE
This register contains the format information of
the serial line. The bit definitions are:
Bits 0 and 1
These two bits specify the number of bits in
each transmitted or received serial character.
The encoding of bits 0 and 1 is as follows:
BIT 1
0
0
1
1
BIT 0 WORD LENGTH
5 Bits
0
6 Bits
1
7 Bits
0
8 Bits
1
The Start, Stop and Parity bits are not included
in the word length.
Bit 2
This bit specifies the number of stop bits in each
transmitted or received serial character. The
following table summarizes the information.
This 8 bit register controls the interface with the
MODEM or data set (or device emulating a
MODEM). The contents of the MODEM control
register are described below.
Bit 0
This bit controls the Data Terminal Ready
(nDTR) output. When bit 0 is set to a logic "1",
the nDTR output is forced to a logic "0". When
bit 0 is a logic "0", the nDTR output is forced to
a logic "1".
Note: The receiver will ignore all stop bits
beyond the first, regardless of the number used
in transmitting.
Bit 3
Parity Enable bit. When bit 3 is a logic "1", a
parity bit is generated (transmit data) or
checked (receive data) between the last data
word bit and the first stop bit of the serial data.
(The parity bit is used to generate an even or
70
operational but the interrupts' sources are now
the lower four bits of the MODEM Control
Register instead of the MODEM Control inputs.
The interrupts are still controlled by the Interrupt
Enable Register.
Bits 5 through 7
These bits are permanently set to logic zero.
Bit 1
This bit controls the Request To Send (nRTS)
output. Bit 1 affects the nRTS output in a
manner identical to that described above for bit
0.
Bit 2
This bit controls the Output 1 (OUT1) bit. This
bit does not have an output pin and can only be
read or written by the CPU.
Bit 3
Output 2 (OUT2). This bit is used to enable an
UART interrupt. When OUT2 is a logic "0", the
serial port interrupt output is forced to a high
impedance state - disabled. When OUT2 is a
logic "1", the serial port interrupt outputs are
enabled.
Bit 4
This bit provides the loopback feature for
diagnostic testing of the Serial Port. When bit 4
is set to logic "1", the following occur:
1.
2.
3.
4.
5.
6.
7.
LINE STATUS REGISTER (LSR)
Address Offset = 5H, DLAB = X, READ/WRITE
Bit 0
Data Ready (DR). It is set to a logic "1"
whenever a complete incoming character has
been received and transferred into the Receiver
Buffer Register or the FIFO. Bit 0 is reset to a
logic "0" by reading all of the data in the Receive
Buffer Register or the FIFO.
Bit 1
Overrun Error (OE). Bit 1 indicates that data in
the Receiver Buffer Register was not read before
the next character was transferred into the
register, thereby destroying the previous
character. In FIFO mode, an overrunn error will
occur only when the FIFO is full and the next
character has been completely received in the
shift register, the character in the shift register is
overwritten but not transferred to the FIFO. The
OE indicator is set to a logic "1" immediately
upon detection of an overrun condition, and
reset whenever the Line Status Register is read.
Bit 2
Parity Error (PE). Bit 2 indicates that the
received data character does not have the
correct even or odd parity, as selected by the
even parity select bit. The PE is set to a logic
"1" upon detection of a parity error and is reset
to a logic "0" whenever the Line Status Register
is read.
In the FIFO mode this error is
associated with the particular character in the
FIFO it applies to. This error is indicated when
the associated character is at the top of the
FIFO.
The TXD is set to the Marking State(logic
"1").
The receiver Serial Input (RXD) is
disconnected.
The output of the Transmitter Shift
Register is "looped back" into the Receiver
Shift Register input.
All MODEM Control inputs (nCTS, nDSR,
nRI and nDCD) are disconnected.
The four MODEM Control outputs (nDTR,
nRTS, OUT1 and OUT2) are internally
connected to the four MODEM Control
inputs (nDSR, nCTS, RI, DCD).
The Modem Control output pins are forced
inactive high.
Data that is transmitted is immediately
received.
This feature allows the processor to verify the
transmit and receive data paths of the Serial
Port. In the diagnostic mode, the receiver and
the transmitter interrupts are fully operational.
The MODEM Control Interrupts are also
71
transferred from the Transmitter Holding
Register into the Transmitter Shift Register. The
bit is reset to logic "0" whenever the CPU loads
the Transmitter Holding Register. In the FIFO
mode this bit is set when the XMIT FIFO is
empty, it is cleared when at least 1 byte is
written to the XMIT FIFO. Bit 5 is a read only
bit.
Bit 6
Transmitter Empty (TEMT). Bit 6 is set to a
logic "1" whenever the Transmitter Holding
Register (THR) and Transmitter Shift Register
(TSR) are both empty. It is reset to logic "0"
whenever either the THR or TSR contains a data
character. Bit 6 is a read only bit. In the FIFO
mode this bit is set whenever the THR and TSR
are both empty,
Bit 7
This bit is permanently set to logic "0" in the 450
mode. In the FIFO mode, this bit is set to a
logic "1" when there is at least one parity error,
framing error or break indication in the FIFO.
This bit is cleared when the LSR is read if there
are no subsequent errors in the FIFO.
Bit 3
Framing Error (FE). Bit 3 indicates that the
received character did not have a valid stop bit.
Bit 3 is set to a logic "1" whenever the stop bit
following the last data bit or parity bit is detected
as a zero bit (Spacing level). The FE is reset to
a logic "0" whenever the Line Status Register is
read. In the FIFO mode this error is associated
with the particular character in the FIFO it
applies to. This error is indicated when the
associated character is at the top of the FIFO.
The Serial Port will try to resynchronize after a
framing error. To do this, it assumes that the
framing error was due to the next start bit, so it
samples this 'start' bit twice and then takes in
the 'data'.
Bit 4
Break Interrupt (BI). Bit 4 is set to a logic "1"
whenever the received data input is held in the
Spacing state (logic "0") for longer than a full
word transmission time (that is, the total time of
the start bit + data bits + parity bits + stop bits).
The BI is reset after the CPU reads the contents
of the Line Status Register. In the FIFO mode
this error is associated with the particular
character in the FIFO it applies to. This error is
indicated when the associated character is at
the top of the FIFO. When break occurs only
one zero character is loaded into the FIFO.
Restarting after a break is received, requires the
serial data (RXD) to be logic "1" for at least 1/2
bit time.
MODEM STATUS REGISTER (MSR)
Address Offset = 6H, DLAB = X, READ/WRITE
This 8 bit register provides the current state of
the control lines from the MODEM (or peripheral
device).
In addition to this current state
information, four bits of the MODEM Status
Register (MSR) provide change information.
These bits are set to logic "1" whenever a
control input from the MODEM changes state.
They are reset to logic "0" whenever the
MODEM Status Register is read.
Bit 0
Delta Clear To Send (DCTS). Bit 0 indicates
that the nCTS input to the chip has changed
state since the last time the MSR was read.
Bit 1
Delta Data Set Ready (DDSR). Bit 1 indicates
that the nDSR input has changed state since the
last time the MSR was read.
Note: Bits 1 through 4 are the error conditions
that produce a Receiver Line Status Interrupt
whenever any of the corresponding conditions
are detected and the interrupt is enabled.
Bit 5
Transmitter Holding Register Empty (THRE).
Bit 5 indicates that the Serial Port is ready to
accept a new character for transmission. In
addition, this bit causes the Serial Port to issue
an interrupt when the Transmitter Holding
Register interrupt enable is set high. The THRE
bit is set to a logic "1" when a character is
72
SCRATCHPAD REGISTER (SCR)
Address Offset =7H, DLAB =X, READ/WRITE
This 8 bit read/write register has no effect on the
operation of the Serial Port. It is intended as a
scratchpad register to be used by the
programmer to hold data temporarily.
Bit 2
Trailing Edge of Ring Indicator (TERI). Bit 2
indicates that the nRI input has changed from
logic "0" to logic "1".
Bit 3
Delta Data Carrier Detect (DDCD).
Bit 3
indicates that the nDCD input to the chip has
changed state.
PROGRAMMABLE BAUD RATE GENERATOR
(AND DIVISOR LATCHES DLH, DLL)
The Serial Port contains a programmable Baud
Rate Generator that is capable of taking any
clock input (DC to 3 MHz) and dividing it by any
divisor from 1 to 65535. This output frequency
of the Baud Rate Generator is 16x the Baud
rate. Two 8 bit latches store the divisor in 16 bit
binary format. These Divisor Latches must be
loaded during initialization in order to insure
desired operation of the Baud Rate Generator.
Upon loading either of the Divisor Latches, a 16
bit Baud counter is immediately loaded. This
prevents long counts on initial load. If a 0 is
loaded into the BRG registers the output divides
the clock by the number 3. If a 1 is loaded the
output is the inverse of the input oscillator. If a
two is loaded the output is a divide by 2 signal
with a 50% duty cycle. If a 3 or greater is
loaded the output is low for 2 bits and high for
the remainder of the count. The input clock to
the BRG is a 1.8462 MHz clock.
Note: Whenever bit 0, 1, 2, or 3 is set to a logic
"1", a MODEM Status Interrupt is generated.
Bit 4
This bit is the complement of the Clear To Send
(nCTS) input. If bit 4 of the MCR is set to logic
"1", this bit is equivalent to nRTS in the MCR.
Bit 5
This bit is the complement of the Data Set
Ready (nDSR) input. If bit 4 of the MCR is set
to logic "1", this bit is equivalent to DTR in the
MCR.
Bit 6
This bit is the complement of the Ring Indicator
(nRI) input. If bit 4 of the MCR is set to logic
"1", this bit is equivalent to OUT1 in the MCR.
Bit 7
This bit is the complement of the Data Carrier
Detect (nDCD) input. If bit 4 of the MCR is set
to logic "1", this bit is equivalent to OUT2 in the
MCR.
Table 31 shows the baud rates possible with a
1.8462 MHz crystal.
Effect Of The Reset on Register File
The Reset Function Table (Table 32) details the
effect of the Reset input on each of the registers
of the Serial Port.
73
B. Character times are calculated by using the
RCLK input for a clock signal (this makes
the delay proportional to the baudrate).
FIFO INTERRUPT MODE OPERATION
When the RCVR FIFO and receiver interrupts
are enabled (FCR bit 0 = "1", IER bit 0 = "1"),
RCVR interrupts occur as follows:
A. The receive data available interrupt will
issued when the FIFO has reached
programmed trigger level; it is cleared
soon as the FIFO drops below
programmed trigger level.
C. When a timeout interrupt has occurred it is
cleared and the timer reset when the CPU
reads one character from the RCVR FIFO.
be
its
as
its
D. When a timeout interrupt has not occurred
the timeout timer is reset after a new
character is received or after the CPU reads
the RCVR FIFO.
B. The IIR receive data available indication also
occurs when the FIFO trigger level is
reached. It is cleared when the FIFO drops
below the trigger level.
When the XMIT FIFO and transmitter interrupts
are enabled (FCR bit 0 = "1", IER bit 1 = "1"),
XMIT interrupts occur as follows:
A. The transmitter holding register interrupt
(02H) occurs when the XMIT FIFO is empty;
it is cleared as soon as the transmitter
holding register is written to (1 of 16
characters may be written to the XMIT FIFO
while servicing this interrupt) or the IIR is
read.
C. The receiver line status interrupt (IIR=06H),
has higher priority than the received data
available (IIR=04H) interrupt.
D. The data ready bit (LSR bit 0) is set as soon
as a character is transferred from the shift
register to the RCVR FIFO. It is reset when
the FIFO is empty.
B. The transmitter FIFO empty indications will
be delayed 1 character time minus the last
stop bit time whenever the following occurs:
THRE=1 and there have not been at least
two bytes at the same time in the transmitter
FIFO since the last THRE=1. The transmitter
interrupt after changing FCR0 will be
immediate, if it is enabled.
When RCVR FIFO and receiver interrupts are
enabled, RCVR FIFO timeout interrupts occur
as follows:
A.
-
-
A FIFO timeout interrupt occurs if all the
following conditions exist:
At least one character is in the FIFO.
The most recent serial character received
was longer than 4 continuous character
times ago. (If 2 stop bits are programmed,
the second one is included in this time
delay).
The most recent CPU read of the FIFO was
longer than 4 continuous character times
ago.
Character timeout and RCVR FIFO trigger level
interrupts have the same priority as the current
received data available interrupt; XMIT FIFO
empty has the same priority as the current
transmitter holding register empty interrupt.
This will cause a maximum character received
to interrupt issued delay of 160 msec at 300
BAUD with a 12 bit character.
74
FIFO POLLED MODE OPERATION
With FCR bit 0 = "1" resetting IER bits 0, 1, 2 or
3 or all to zero puts the UART in the FIFO
Polled Mode of operation. Since the RCVR and
XMITTER are controlled separately, either one
or both can be in the polled mode of operation.
In this mode, the user's program will check
RCVR and XMITTER status via the LSR. LSR
definitions for the FIFO Polled Mode are as
follows:
-
-
the same way as when in the interrupt
mode, the IIR is not affected since EIR bit
2=0.
Bit 5 indicates when the XMIT FIFO is
empty.
Bit 6 indicates that both the XMIT FIFO and
shift register are empty.
Bit 7 indicates whether there are any errors
in the RCVR FIFO.
There is no trigger level reached or timeout
condition indicated in the FIFO Polled Mode,
however, the RCVR and XMIT FIFOs are still
fully capable of holding characters.
Bit 0=1 as long as there is one byte in the
RCVR FIFO.
Bits 1 to 4 specify which error(s) have
occurred. Character error status is handled
Table 31 - Baud Rates Using 1.8462 MHz Clock for <= 38.4K; Using 1.8432MHz Clock
for 115.2k ; Using 3.6864MHz Clock for 230.4k; Using 7.3728 MHz Clock for 460.8k
DESIRED
DIVISOR USED TO
PERCENT ERROR DIFFERENCE
HIGH
BAUD RATE
GENERATE 16X CLOCK
BETWEEN DESIRED AND ACTUAL1 SPEED BIT2
50
2304
0.001
X
75
1536
X
110
1047
X
134.5
857
0.004
X
150
768
X
300
384
X
600
192
X
1200
96
X
1800
64
X
2000
58
0.005
X
2400
48
X
3600
32
X
4800
24
X
7200
16
X
9600
12
X
19200
6
X
38400
3
0.030
X
57600
2
0.16
X
115200
1
0.16
X
230400
32770
0.16
1
75
DESIRED
DIVISOR USED TO
PERCENT ERROR DIFFERENCE
HIGH
BAUD RATE
GENERATE 16X CLOCK
BETWEEN DESIRED AND ACTUAL1 SPEED BIT2
460800
32769
0.16
1
1
Note : The percentage error for all baud rates, except where indicated otherwise, is 0.2%.
Note 2: The High Speed bit is located in the Device Configuration Space.
REGISTER/SIGNAL
Table 32 - Reset Function Table
RESET CONTROL
RESET STATE
Interrupt Enable Register
RESET
All bits low
Interrupt Identification Reg.
RESET
Bit 0 is high; Bits 1 - 7 low
FIFO Control
RESET
All bits low
Line Control Reg.
RESET
All bits low
MODEM Control Reg.
RESET
All bits low
Line Status Reg.
RESET
All bits low except 5, 6 high
MODEM Status Reg.
RESET
Bits 0 - 3 low; Bits 4 - 7 input
TXD1, TXD2
RESET
High
INTRPT (RCVR errs)
RESET/Read LSR
Low
INTRPT (RCVR Data Ready)
RESET/Read RBR
Low
INTRPT (THRE)
RESET/ReadIIR/Write THR
Low
OUT2B
RESET
High
RTSB
RESET
High
DTRB
RESET
High
OUT1B
RESET
High
RCVR FIFO
RESET/
FCR1*FCR0/_FCR0
All Bits Low
XMIT FIFO
RESET/
FCR1*FCR0/_FCR0
All Bits Low
76
Table 33 - Register Summary for an Individual UART Channel
REGISTER
ADDRESS*
REGISTER
SYMBOL
REGISTER NAME
BIT 0
BIT 1
ADDR = 0
DLAB = 0
Receive Buffer Register (Read Only)
RBR
Data Bit 0
(Note 1)
Data Bit 1
ADDR = 0
DLAB = 0
Transmitter Holding Register (Write Only)
THR
Data Bit 0
Data Bit 1
ADDR = 1
DLAB = 0
Interrupt Enable Register
IER
Enable
Received Data
Available
Interrupt
(ERDAI)
Enable
Transmitter
Holding
Register
Empty
Interrupt
(ETHREI)
ADDR = 2
Interrupt Ident. Register (Read Only)
IIR
"0" if Interrupt
Pending
Interrupt ID Bit
ADDR = 2
FIFO Control Register (Write Only)
FCR (Note
7)
FIFO Enable
RCVR FIFO
Reset
ADDR = 3
Line Control Register
LCR
Word Length
Select Bit 0
(WLS0)
Word Length
Select Bit 1
(WLS1)
ADDR = 4
MODEM Control Register
MCR
Data Terminal
Ready (DTR)
Request to
Send (RTS)
ADDR = 5
Line Status Register
LSR
Data Ready
(DR)
Overrun Error
(OE)
ADDR = 6
MODEM Status Register
MSR
Delta Clear to
Send (DCTS)
Delta Data Set
Ready
(DDSR)
ADDR = 7
Scratch Register (Note 4)
SCR
Bit 0
Bit 1
ADDR = 0
DLAB = 1
Divisor Latch (LS)
DDL
Bit 0
Bit 1
ADDR = 1
DLAB = 1
Divisor Latch (MS)
DLM
Bit 8
Bit 9
*DLAB is Bit 7 of the Line Control Register (ADDR = 3).
Note 1: Bit 0 is the least significant bit. It is the first bit serially transmitted or received.
Note 2: When operating in the XT mode, this bit will be set any time that the transmitter shift
register is empty.
77
Table 33 - Register Summary for an Individual UART Channel (continued)
BIT 2
BIT 3
BIT 4
BIT 5
BIT 6
BIT 7
Data Bit 2
Data Bit 3
Data Bit 4
Data Bit 5
Data Bit 6
Data Bit 7
Data Bit 2
Data Bit 3
Data Bit 4
Data Bit 5
Data Bit 6
Data Bit 7
Enable
Receiver Line
Status
Interrupt
(ELSI)
Enable
MODEM
Status
Interrupt
(EMSI)
0
0
0
0
Interrupt ID
Bit
Interrupt ID
Bit (Note 5)
0
0
FIFOs
Enabled
(Note 5)
FIFOs
Enabled
(Note 5)
XMIT FIFO
Reset
Reserved
DMA Mode
Select (Note
6)
Reserved
RCVR Trigger RCVR Trigger
LSB
MSB
Number of
Stop Bits
(STB)
Parity Enable
(PEN)
Even Parity
Select (EPS)
Stick Parity
Set Break
Divisor Latch
Access Bit
(DLAB)
OUT1
(Note 3)
OUT2
(Note 3)
Loop
0
0
0
Parity Error
(PE)
Framing Error Break
(FE)
Interrupt (BI)
Transmitter
Holding
Register
(THRE)
Transmitter
Empty
(TEMT)
(Note 2)
Error in
RCVR FIFO
(Note 5)
Trailing Edge Delta Data
Clear to Send
Ring Indicator Carrier Detect (CTS)
(TERI)
(DDCD)
Data Set
Ready (DSR)
Ring Indicator Data Carrier
Detect (DCD)
(RI)
Bit 2
Bit 3
Bit 4
Bit 5
Bit 6
Bit 7
Bit 2
Bit 3
Bit 4
Bit 5
Bit 6
Bit 7
Bit 10
Bit 11
Bit 12
Bit 13
Bit 14
Bit 15
Note 3: This bit no longer has a pin associated with it.
Note 4: When operating in the XT mode, this register is not available.
Note 5: These bits are always zero in the non-FIFO mode.
Note 6: Writing a one to this bit has no effect. DMA modes are not supported in this chip.
Note 7: The UART1 and UART2 FCR’s are shadowed in the UART1 FIFO Control Shadow
Register (LD8:CRC3[7:0]) and UART2 FIFO Control Shadow Register (LD8:CRC4[7:0]).
78
until at least two bytes have the Tx FIFO
empties after this condition, the Tx been
loaded into the FIFO, concurrently. When
interrupt will be activated without a one
character delay.
NOTES ON SERIAL PORT OPERATION
FIFO MODE OPERATION:
GENERAL
The RCVR FIFO will hold up to 16 bytes
regardless of which trigger level is selected.
Rx support functions and operation are quite
different from those described for the
transmitter. The Rx FIFO receives data until the
number of bytes in the FIFO equals the selected
interrupt trigger level.
At that time if Rx
interrupts are enabled, the UART will issue an
interrupt to the CPU. The Rx FIFO will continue
to store bytes until it holds 16 of them. It will
not accept any more data when it is full. Any
more data entering the Rx shift register will set
the Overrun Error flag. Normally, the FIFO
depth and the programmable trigger levels will
give the CPU ample time to empty the Rx FIFO
before an overrun occurs.
TX AND RX FIFO OPERATION
The Tx portion of the UART transmits data
through TXD as soon as the CPU loads a byte
into the Tx FIFO. The UART will prevent
loads to the Tx FIFO if it currently holds 16
characters. Loading to the Tx FIFO will again
be enabled as soon as the next character is
transferred to the Tx shift register. These
capabilities account for the largely autonomous
operation of the Tx.
The UART starts the above operations typically
with a Tx interrupt. The chip issues a Tx
interrupt whenever the Tx FIFO is empty and the
Tx interrupt is enabled, except in the following
instance. Assume that the Tx FIFO is empty
and the CPU starts to load it. When the first
byte enters the FIFO the Tx FIFO empty
interrupt will transition from active to inactive.
Depending on the execution speed of the service
routine software, the UART may be able to
transfer this byte from the FIFO to the shift
register before the CPU loads another byte. If
this happens, the Tx FIFO will be empty again
and typically the UART's interrupt line would
transition to the active state. This could cause a
system with an interrupt control unit to record a
Tx FIFO empty condition, even though the CPU
is currently servicing that interrupt. Therefore,
after the first byte has been loaded into the
FIFO the UART will wait one serial character
transmission time before issuing a new Tx
FIFO empty interrupt. This one character Tx
interrupt
delay
will
remain
active
One side-effect of having a Rx FIFO is that the
selected interrupt trigger level may be above the
data level in the FIFO. This could occur when
data at the end of the block contains fewer bytes
than the trigger level. No interrupt would be
issued to the CPU and the data would remain in
the UART. To prevent the software from
having to check for this situation the chip
incorporates a timeout interrupt.
The timeout interrupt is activated when there is
a least one byte in the Rx FIFO, and neither the
CPU nor the Rx shift register has accessed the
Rx FIFO within 4 character times of the last
byte. The timeout interrupt is cleared or reset
when the CPU reads the Rx FIFO or another
character enters it.
These FIFO related features allow optimization
of CPU/UART transactions and are especially
useful given the higher baud rate capability (256
kbaud).
79
INFRARED INTERFACE
The Amplitude Shift Keyed IR allows
asynchronous serial communication at baud
rates up to 19.2K Baud. Each word is sent
serially beginning with a zero value start bit. A
zero is signaled by sending a 500KHz waveform
for the duration of the serial bit time. A one is
signaled by sending no transmission during the
bit time. Please refer to the AC timing for the
parameters of the ASK-IR waveform.
The infrared interface provides a two-way
wireless communications port using infrared as
a
transmission
medium.
Several
IR
implementations have been provided for the
second UART in this chip (logical device 5),
IrDA, Consumer Remote Control, and Amplitude
Shift Keyed IR. The IR transmission can use
the standard UART2 TXD2 and RXD2 pins or
optional IRTX and IRRX pins. These can be
selected through the configuration registers.
If the Half Duplex option is chosen, there is a
time-out when the direction of the transmission
is changed. This time-out starts at the last bit
transferred during a transmission and blocks the
receiver input until the timeout expires. If the
transmit buffer is loaded with more data before
the time-out expires, the timer is restarted after
the new byte is transmitted. If data is loaded
into the transmit buffer while a character is
being received, the transmission will not start
until the time-out expires after the last receive
bit has been received. If the start bit of another
character is received during this time-out, the
timer is restarted after the new character is
received. The IR half duplex time-out is
programmable via CRF2 in Logical Device 5.
This register allows the time-out to be
programmed to any value between 0 and
10msec in 100usec increments.
IrDA 1.0 allows serial communication at baud
rates up to 115.2 kbps. Each word is sent
serially beginning with a zero value start bit. A
zero is signaled by sending a single IR pulse at
the beginning of the serial bit time. A one is
signaled by sending no IR pulse during the bit
time. Please refer to the AC timing for the
parameters of these pulses and the IrDA
waveform.
The consumer remote control interface can
decode NEC PPM remote control frames in
hardware as well provide a general-purpose
synchronous
ASK
encoder/decoder
with
programmable carrier frequency and bit rates to
emulate many other popular remote control
encoding formats; including 38 kHz PPM, PWM
and RC-5. Consult the SMSC CIrCC data
sheet for more details.
80
PARALLEL PORT
The parallel port also incorporates SMSC's
ChiProtect circuitry, which prevents possible
damage to the parallel port due to printer powerup.
The FDC37B77x incorporates an IBM XT/AT
compatible parallel port. This supports the
optional PS/2 type bi-directional parallel port
(SPP), the Enhanced Parallel Port (EPP) and
the Extended Capabilities Port (ECP) parallel
port modes.
Refer to the Configuration
Registers for information on disabling, power
down, changing the base address of the parallel
port, and selecting the mode of operation.
The functionality of the Parallel Port is achieved
through the use of eight addressable ports, with
their associated registers and control gating.
The control and data port are read/write by the
CPU, the status port is read/write in the EPP
mode. The address map of the Parallel Port is
shown below:
The FDC37B77x also provides a mode for
support of the floppy disk controller on the
parallel port.
DATA PORT
STATUS PORT
CONTROL PORT
EPP ADDR PORT
EPP DATA PORT 0
EPP DATA PORT 1
EPP DATA PORT 2
EPP DATA PORT 3
BASE ADDRESS + 00H
BASE ADDRESS + 01H
BASE ADDRESS + 02H
BASE ADDRESS + 03H
BASE ADDRESS + 04H
BASE ADDRESS + 05H
BASE ADDRESS + 06H
BASE ADDRESS + 07H
The bit map of these registers is:
D0
D1
D2
D3
D4
D5
D6
D7
PD0
PD1
PD2
PD3
PD4
PD5
PD6
PD7
1
STATUS
PORT
TMOUT
0
0
nERR
SLCT
PE
nACK
nBUSY
1
CONTROL
PORT
STROBE
AUTOFD
nINIT
SLC
IRQE
PCD
0
0
1
EPP ADDR
PORT
PD0
PD1
PD2
PD3
PD4
PD5
PD6
AD7
2,3
EPP DATA
PORT 0
PD0
PD1
PD2
PD3
PD4
PD5
PD6
PD7
2,3
EPP DATA
PORT 1
PD0
PD1
PD2
PD3
PD4
PD5
PD6
PD7
2,3
EPP DATA
PORT 2
PD0
PD1
PD2
PD3
PD4
PD5
PD6
PD7
2,3
EPP DATA
PORT 3
PD0
PD1
PD2
PD3
PD4
PD5
PD6
PD7
2,3
DATA PORT
Note 1: These registers are available in all modes.
Note 2: These registers are only available in EPP mode.
Note 3: For EPP mode, IOCHRDY must be connected to the ISA bus.
81
Note
Table 34 - Parallel Port Connector
HOST
CONNECTOR
PIN NUMBER
1
STANDARD
EPP
ECP
nStrobe
nWrite
nStrobe
2-9
PData<0:7>
PData<0:7>
PData<0:7>
10
nAck
Intr
nAck
11
Busy
nWait
Busy, PeriphAck(3)
12
PE
(NU)
PError,
nAckReverse(3)
13
Select
(NU)
Select
14
nAutofd
nDatastb
nAutoFd,
HostAck(3)
15
nError
(NU)
nFault(1)
nPeriphRequest(3)
16
nInit
(NU)
nInit(1)
nReverseRqst(3)
17
nSelectin
nAddrstrb
nSelectIn(1,3)
(1) = Compatible Mode
(3) = High Speed Mode
Note:
For the cable interconnection required for ECP support and the Slave Connector pin
numbers, refer to the IEEE 1284 Extended Capabilities Port Protocol and ISA Standard, Rev.
1.14, July 14, 1993. This document is available from Microsoft.
82
BIT 3 nERR - nERROR
The level on the nERROR input is read by the
CPU as bit 3 of the Printer Status Register. A
logic 0 means an error has been detected; a
logic 1 means no error has been detected.
IBM XT/AT COMPATIBLE, BI-DIRECTIONAL
AND EPP MODES
DATA PORT
ADDRESS OFFSET = 00H
BIT 4 SLCT - PRINTER SELECTED STATUS
The level on the SLCT input is read by the CPU
as bit 4 of the Printer Status Register. A logic 1
means the printer is on line; a logic 0 means it is
not selected.
The Data Port is located at an offset of '00H'
from the base address. The data register is
cleared at initialization by RESET. During a
WRITE operation, the Data Register latches the
contents of the data bus with the rising edge of
the nIOW input. The contents of this register
are buffered (non inverting) and output onto the
PD0 - PD7 ports. During a READ operation in
SPP mode, PD0 - PD7 ports are buffered (not
latched) and output to the host CPU.
BIT 5 PE - PAPER END
The level on the PE input is read by the CPU as
bit 5 of the Printer Status Register. A logic 1
indicates a paper end; a logic 0 indicates the
presence of paper.
STATUS PORT
ADDRESS OFFSET = 01H
BIT 6 nACK - nACKNOWLEDGE
The level on the nACK input is read by the CPU
as bit 6 of the Printer Status Register. A logic 0
means that the printer has received a character
and can now accept another. A logic 1 means
that it is still processing the last character or has
not received the data.
The Status Port is located at an offset of '01H'
from the base address. The contents of this
register are latched for the duration of an nIOR
read cycle. The bits of the Status Port are
defined as follows:
BIT 0 TMOUT - TIME OUT
This bit is valid in EPP mode only and indicates
that a 10 usec time out has occurred on the
EPP bus. A logic O means that no time out
error has occurred; a logic 1 means that a time
out error has been detected. This bit is cleared
by a RESET. Writing a one to this bit clears the
time out status bit. On a write, this bit is self
clearing and does not require a write of a zero.
Writing a zero to this bit has no effect.
BIT 7 nBUSY - nBUSY
The complement of the level on the BUSY input
is read by the CPU as bit 7 of the Printer Status
Register. A logic 0 in this bit means that the
printer is busy and cannot accept a new
character. A logic 1 means that it is ready to
accept the next character.
BITS 1, 2 - are not implemented as register bits,
during a read of the Printer Status Register
these bits are a low level.
The Control Port is located at an offset of '02H'
from the base address. The Control Register is
initialized by the RESET input, bits 0 to 5 only
being affected; bits 6 and 7 are hard wired low.
CONTROL PORT
ADDRESS OFFSET = 02H
83
The EPP Address Port is located at an offset of
'03H' from the base address. The address
register is cleared at initialization by RESET.
During a WRITE operation, the contents of DB0DB7 are buffered (non inverting) and output onto
the PD0 - PD7 ports, the leading edge of nIOW
causes an EPP ADDRESS WRITE cycle to be
performed, the trailing edge of IOW latches the
data for the duration of the EPP write cycle.
During a READ operation, PD0 - PD7 ports are
read, the leading edge of IOR causes an EPP
ADDRESS READ cycle to be performed and the
data output to the host CPU, the deassertion of
ADDRSTB latches the PData for the duration of
the IOR cycle. This register is only available in
EPP mode.
BIT 0 STROBE - STROBE
This bit is inverted and output onto the
nSTROBE output.
BIT 1 AUTOFD - AUTOFEED
This bit is inverted and output onto the
nAUTOFD output. A logic 1 causes the printer
to generate a line feed after each line is printed.
A logic 0 means no autofeed.
BIT 2 nINIT - nINITIATE OUTPUT
This bit is output onto the nINIT output without
inversion.
BIT 3 SLCTIN - PRINTER SELECT INPUT
This bit is inverted and output onto the nSLCTIN
output. A logic 1 on this bit selects the printer; a
logic 0 means the printer is not selected.
EPP DATA PORT 0
ADDRESS OFFSET = 04H
BIT 4 IRQE - INTERRUPT REQUEST ENABLE
The interrupt request enable bit when set to a
high level may be used to enable interrupt
requests from the Parallel Port to the CPU. An
interrupt request is generated on the IRQ port by
a positive going nACK input. When the IRQE
bit is programmed low the IRQ is disabled.
The EPP Data Port 0 is located at an offset of
'04H' from the base address. The data register
is cleared at initialization by RESET. During a
WRITE operation, the contents of DB0-DB7 are
buffered (non inverting) and output onto the PD0
- PD7 ports, the leading edge of nIOW causes
an EPP DATA WRITE cycle to be performed,
the trailing edge of IOW latches the data for the
duration of the EPP write cycle. During a READ
operation, PD0 - PD7 ports are read, the leading
edge of IOR causes an EPP READ cycle to be
performed and the data output to the host CPU,
the deassertion of DATASTB latches the PData
for the duration of the IOR cycle. This register
is only available in EPP mode.
BIT 5
PCD - PARALLEL CONTROL
DIRECTION
Parallel Control Direction is not valid in printer
mode. In printer mode, the direction is always
out regardless of the state of this bit. In bidirectional, EPP or ECP mode, a logic 0 means
that the printer port is in output mode (write); a
logic 1 means that the printer port is in input
mode (read).
EPP DATA PORT 1
ADDRESS OFFSET = 05H
Bits 6 and 7 during a read are a low level, and
cannot be written.
The EPP Data Port 1 is located at an offset of
'05H' from the base address. Refer to EPP
DATA PORT 0 for a description of operation.
This register is only available in EPP mode.
EPP ADDRESS PORT
ADDRESS OFFSET = 03H
84
Read, Write or Address cycle is currently
executing, then the PDx bus is in the standard or
bi-directional mode, and all output signals
(STROBE, AUTOFD, INIT) are as set by the
SPP Control Port and direction is controlled by
PCD of the Control port.
EPP DATA PORT 2
ADDRESS OFFSET = 06H
The EPP Data Port 2 is located at an offset of
'06H' from the base address. Refer to EPP
DATA PORT 0 for a description of operation.
This register is only available in EPP mode.
In EPP mode, the system timing is closely
coupled to the EPP timing. For this reason, a
watchdog timer is required to prevent system
lockup. The timer indicates if more than 10usec
have elapsed from the start of the EPP cycle
(nIOR or nIOW asserted) to nWAIT being
deasserted (after command). If a time-out
occurs, the current EPP cycle is aborted and the
time-out condition is indicated in Status bit 0.
EPP DATA PORT 3
ADDRESS OFFSET = 07H
The EPP Data Port 3 is located at an offset of
'07H' from the base address. Refer to EPP
DATA PORT 0 for a description of operation.
This register is only available in EPP mode.
EPP 1.9 OPERATION
During an EPP cycle, if STROBE is active, it
overrides the EPP write signal forcing the PDx
bus to always be in a write mode and the
nWRITE signal to always be asserted.
When the EPP mode is selected in the
configuration register, the standard and bidirectional modes are also available. If no EPP
85
5.
Software Constraints
Before an EPP cycle is executed, the software
must ensure that the control register bit PCD is
a logic "0" (ie a 04H or 05H should be written to
the Control port). If the user leaves PCD as a
logic "1", and attempts to perform an EPP write,
the chip is unable to perform the write (because
PCD is a logic "1") and will appear to perform an
EPP read on the parallel bus, no error is
indicated.
6.
7.
EPP 1.9 Write
The timing for a write operation (address or
data) is shown in timing diagram EPP Write
Data or Address cycle. IOCHRDY is driven
active low at the start of each EPP write and is
released when it has been determined that the
write cycle can complete. The write cycle can
complete under the following circumstances:
1.
2.
8.
9.
If the EPP bus is not ready (nWAIT is active
low) when nDATASTB or nADDRSTB goes
active then the write can complete when
nWAIT goes inactive high.
EPP 1.9 Read
The timing for a read operation (data) is shown
in timing diagram EPP Read Data cycle.
IOCHRDY is driven active low at the start of
each EPP read and is released when it has been
determined that the read cycle can complete.
The read cycle can complete under the following
circumstances:
If the EPP bus is ready (nWAIT is inactive
high) then the chip must wait for it to go
active low before changing the state of
nDATASTB, nWRITE or nADDRSTB. The
write can complete once nWAIT is
determined inactive.
1
If the EPP bus is not ready (nWAIT is active
low) when nDATASTB goes active then the
read can complete when nWAIT goes
inactive high.
2.
If the EPP bus is ready (nWAIT is inactive
high) then the chip must wait for it to go
active low before changing the state of
WRITE or before nDATASTB goes active.
The read can complete once nWAIT is
determined inactive.
Write Sequence of operation
1.
2.
3.
4.
Chip asserts nDATASTB or nADDRSTRB
indicating that PData bus contains valid
information, and the WRITE signal is valid.
Peripheral deasserts nWAIT, indicating that
any setup requirements have been satisfied
and the chip may begin the termination
phase of the cycle.
a) The chip deasserts nDATASTB or
nADDRSTRB, this marks the beginning
of the termination phase. If it has not
already done so, the peripheral should
latch the information byte now.
b) The chip latches the data from the
SData bus for the PData bus and
asserts (releases) IOCHRDY allowing
the host to complete the write cycle.
Peripheral asserts nWAIT, indicating to the
host that any hold time requirements have
been satisfied and acknowledging the
termination of the cycle.
Chip may modify nWRITE and nPDATA in
preparation for the next cycle.
The host selects an EPP register, places
data on the SData bus and drives nIOW
active.
The chip drives IOCHRDY inactive (low).
If WAIT is not asserted, the chip must wait
until WAIT is asserted.
The chip places address or data on PData
bus, clears PDIR, and asserts nWRITE.
86
In EPP mode, the system timing is closely
coupled to the EPP timing. For this reason, a
watchdog timer is required to prevent system
lockup. The timer indicates if more than 10usec
have elapsed from the start of the EPP cycle
(nIOR or nIOW asserted) to the end of the cycle
nIOR or nIOW deasserted).
If a time-out
occurs, the current EPP cycle is aborted and the
time-out condition is indicated in Status bit 0.
Read Sequence of Operation
1.
The host selects an EPP register and drives
nIOR active.
2. The chip drives IOCHRDY inactive (low).
3. If WAIT is not asserted, the chip must wait
until WAIT is asserted.
4. The chip tri-states the PData bus and
deasserts nWRITE.
5. Chip asserts nDATASTB or nADDRSTRB
indicating that PData bus is tri-stated, PDIR
is set and the nWRITE signal is valid.
6. Peripheral drives PData bus valid.
7. Peripheral deasserts nWAIT, indicating that
PData is valid and the chip may begin the
termination phase of the cycle.
8. a) The chip latches the data from the
PData bus for the SData bus and
deasserts nDATASTB or nADDRSTRB.
This marks the beginning of the
termination phase.
b) The chip drives the valid data onto the
SData bus and asserts (releases)
IOCHRDY allowing the host to
complete the read cycle.
9. Peripheral tri-states the PData bus and
asserts nWAIT, indicating to the host that
the PData bus is tri-stated.
10. Chip may modify nWRITE, PDIR and
nPDATA in preparation for the next cycle.
Software Constraints
Before an EPP cycle is executed, the software
must ensure that the control register bits D0, D1
and D3 are set to zero. Also, bit D5 (PCD) is a
logic "0" for an EPP write or a logic "1" for and
EPP read.
EPP 1.7 Write
The timing for a write operation (address or
data) is shown in timing diagram EPP 1.7 Write
Data or Address cycle. IOCHRDY is driven
active low when nWAIT is active low during the
EPP cycle. This can be used to extend the cycle
time.
The write cycle can complete when
nWAIT is inactive high.
Write Sequence of Operation
1.
EPP 1.7 OPERATION
When the EPP 1.7 mode is selected in the
configuration register, the standard and bidirectional modes are also available. If no EPP
Read, Write or Address cycle is currently
executing, then the PDx bus is in the standard or
bi-directional mode, and all output signals
(STROBE, AUTOFD, INIT) are as set by the
SPP Control Port and direction is controlled by
PCD of the Control port.
2.
3.
4.
5.
6.
87
The host sets PDIR bit in the control
register to a logic "0".
This asserts
nWRITE.
The host selects an EPP register, places
data on the SData bus and drives nIOW
active.
The chip places address or data on PData
bus.
Chip asserts nDATASTB or nADDRSTRB
indicating that PData bus contains valid
information, and the WRITE signal is valid.
If nWAIT is asserted, IOCHRDY is
deasserted until the peripheral deasserts
nWAIT or a time-out occurs.
When the host deasserts nIOW the chip
deasserts nDATASTB or nADDRSTRB and
7.
Read Sequence of Operation
latches the data from the SData bus for the
PData bus.
Chip may modify nWRITE, PDIR and
nPDATA in preparation of the next cycle.
1.
EPP 1.7 Read
2.
The timing for a read operation (data) is shown
in timing diagram EPP 1.7 Read Data cycle.
IOCHRDY is driven active low when nWAIT is
active low during the EPP cycle. This can be
used to extend the cycle time. The read cycle
can complete when nWAIT is inactive high.
3.
4.
5.
6.
7.
8.
9.
88
The host sets PDIR bit in the control
register to a logic "1". This deasserts
nWRITE and tri-states the PData bus.
The host selects an EPP register and drives
nIOR active.
Chip asserts nDATASTB or nADDRSTRB
indicating that PData bus is tri-stated, PDIR
is set and the nWRITE signal is valid.
If nWAIT is asserted, IOCHRDY is
deasserted until the peripheral deasserts
nWAIT or a time-out occurs.
The Peripheral drives PData bus valid.
The Peripheral deasserts nWAIT, indicating
that PData is valid and the chip may begin
the termination phase of the cycle.
When the host deasserts nIOR the chip
deasserts nDATASTB or nADDRSTRB.
Peripheral tri-states the PData bus.
Chip may modify nWRITE, PDIR and
nPDATA in preparation of the next cycle.
Table 35 - EPP Pin Descriptions
EPP
SIGNAL
EPP NAME
TYPE
EPP DESCRIPTION
nWRITE
nWrite
O
This signal is active low. It denotes a write operation.
PD<0:7>
Address/Data
I/O
Bi-directional EPP byte wide address and data bus.
INTR
Interrupt
I
This signal is active high and positive edge triggered. (Pass
through with no inversion, Same as SPP).
WAIT
nWait
I
This signal is active low. It is driven inactive as a positive
acknowledgement from the device that the transfer of data is
completed. It is driven active as an indication that the
device is ready for the next transfer.
DATASTB
nData Strobe
O
This signal is active low.
write operation.
RESET
nReset
O
This signal is active low.
When driven active, the EPP
device is reset to its initial operational mode.
ADDRSTB
nAddress
Strobe
O
This signal is active low.
or write operation.
PE
Paper End
I
Same as SPP mode.
SLCT
Printer
Selected
Status
I
Same as SPP mode.
nERR
Error
I
Same as SPP mode.
PDIR
Parallel Port
Direction
O
This output shows the direction of the data transfer on the
parallel port bus. A low means an output/write condition and
a high means an input/read condition. This signal is
normally a low (output/write) unless PCD of the control
register is set or if an EPP read cycle is in progress.
It is used to denote data read or
It is used to denote address read
Note 1: SPP and EPP can use 1 common register.
Note 2: nWrite is the only EPP output that can be over-ridden by SPP control port during an EPP
cycle. For correct EPP read cycles, PCD is required to be a low.
89
reverse: Peripheral to Host communication
Pword: A port word; equal in size to the width
of the ISA interface. For this
implementation, PWord is always 8
bits.
1
A high level.
0
A low level.
EXTENDED CAPABILITIES PARALLEL PORT
ECP provides a number of advantages, some of
which are listed below. The individual features
are explained in greater detail in the remainder
of this section.
•
•
•
•
•
•
•
•
High performance half-duplex forward and
reverse channel
Interlocked handshake, for fast reliable
transfer
Optional single byte RLE compression for
improved throughput (64:1)
Channel addressing for low-cost peripherals
Maintains link and data layer separation
Permits the use of active output drivers
Permits the use of adaptive signal timing
Peer-to-peer capability
These terms may be considered synonymous:
•
•
•
•
•
•
•
•
•
Vocabulary
The following terms are used in this document:
Reference Document: IEEE 1284 Extended
Capabilities Port Protocol and ISA Interface
Standard, Rev 1.14, July 14, 1993.
This
document is available from Microsoft.
assert: When a signal asserts it transitions to a
"true" state, when a signal deasserts it
transitions to a "false" state.
forward: Host to Peripheral communication.
data
ecpAFifo
PeriphClk, nAck
HostAck, nAutoFd
PeriphAck, Busy
nPeriphRequest, nFault
nReverseRequest, nInit
nAckReverse, PError
Xflag, Select
ECPMode, nSelectln
HostClk, nStrobe
The bit map of the Extended Parallel Port
registers is:
D7
D6
D5
D4
D3
D2
D1
D0
PD7
PD6
PD5
PD4
PD3
PD2
PD1
PD0
Addr/RLE
Address or RLE field
Note
2
dsr
nBusy
nAck
PError
Select
nFault
0
0
0
1
dcr
0
0
Direction
ackIntEn
SelectIn
nInit
autofd
strobe
1
cFifo
ecpDFifo
tFifo
2
ECP Data FIFO
2
Test FIFO
cnfgA
0
0
cnfgB
compress
intrValue
ecr
Parallel Port Data FIFO
MODE
0
1
2
0
Parallel Port IRQ
nErrIntrEn
0
0
0
Parallel Port DMA
dmaEn
serviceIntr
full
empty
Note 1: These registers are available in all modes.
Note 2: All FIFOs use one common 16 byte FIFO.
Note 3: The ECP Parallel Port Config Reg B reflects the IRQ and DRQ selected by the Configuration
Registers.
90
rather it provides an automatic high
burst-bandwidth channel that supports DMA for
ECP in both the forward and reverse directions.
ISA IMPLEMENTATION STANDARD
This specification describes the standard ISA
interface to the Extended Capabilities Port
(ECP). All ISA devices supporting ECP must
meet the requirements contained in this section
or the port will not be supported by Microsoft.
For a description of the ECP Protocol, please
refer to the IEEE 1284 Extended Capabilities
Port Protocol and ISA Interface Standard, Rev.
1.14, July 14, 1993. This document is available
from Microsoft.
Small FIFOs are employed in both forward and
reverse directions to smooth data flow and
improve the maximum bandwidth requirement.
The size of the FIFO is 16 bytes deep. The port
supports an automatic handshake for the
standard parallel port to improve compatibility
mode transfer speed.
The port also supports run length encoded
(RLE) decompression (required) in hardware.
Compression is accomplished by counting
identical bytes and transmitting an RLE byte
that indicates how many times the next byte is
to be repeated. Decompression simply
intercepts the RLE byte and repeats the
following byte the specified number of times.
Hardware support for compression is optional.
Description
The port is software and hardware compatible
with existing parallel ports so that it may be
used as a standard LPT port if ECP is not
required. The port is designed to be simple and
requires a small number of gates to implement.
It does not do any "protocol" negotiation,
91
NAME
TYPE
Table 36 - ECP Pin Descriptions
DESCRIPTION
nStrobe
O
During write operations nStrobe registers data or address into the slave
on the asserting edge (handshakes with Busy).
PData 7:0
I/O
Contains address or data or RLE data.
nAck
I
Indicates valid data driven by the peripheral when asserted. This signal
handshakes with nAutoFd in reverse.
PeriphAck (Busy)
I
This signal deasserts to indicate that the peripheral can accept data.
This signal handshakes with nStrobe in the forward direction. In the
reverse direction this signal indicates whether the data lines contain
ECP command information or data. The peripheral uses this signal to
flow control in the forward direction. It is an "interlocked" handshake
with nStrobe. PeriphAck also provides command information in the
reverse direction.
PError
(nAckReverse)
I
Used to acknowledge a change in the direction the transfer (asserted =
forward).
The peripheral drives this signal low to acknowledge
nReverseRequest.
It
is
an
"interlocked"
handshake
with
nReverseRequest. The host relies upon nAckReverse to determine
when it is permitted to drive the data bus.
Select
I
Indicates printer on line.
nAutoFd
(HostAck)
O
Requests a byte of data from the peripheral when asserted,
handshaking with nAck in the reverse direction. In the forward direction
this signal indicates whether the data lines contain ECP address or
data. The host drives this signal to flow control in the reverse direction.
It is an "interlocked" handshake with nAck. HostAck also provides
command information in the forward phase.
nFault
(nPeriphRequest)
I
Generates an error interrupt when asserted. This signal provides a
mechanism for peer-to-peer communication. This signal is valid only in
the forward direction. During ECP Mode the peripheral is permitted
(but not required) to drive this pin low to request a reverse transfer. The
request is merely a "hint" to the host; the host has ultimate control over
the transfer direction. This signal would be typically used to generate
an interrupt to the host CPU.
nInit
O
Sets the transfer direction (asserted = reverse, deasserted = forward).
This pin is driven low to place the channel in the reverse direction. The
peripheral is only allowed to drive the bi-directional data bus while in
ECP Mode and HostAck is low and nSelectIn is high.
nSelectIn
O
Always deasserted in ECP mode.
92
to avoid conflict with standard ISA devices. The
port is equivalent to a generic parallel port
interface and may be operated in that mode.
The port registers vary depending on the mode
field in the ecr. The table below lists these
dependencies. Operation of the devices in
modes other that those specified is undefined.
Register Definitions
The register definitions are based on the
standard IBM addresses for LPT. All of the
standard printer ports are supported.
The
additional registers attach to an upper bit
decode of the standard LPT port definition
Table 37 - ECP Register Definitions
ADDRESS (Note 1)
ECP MODES
NAME
FUNCTION
data
+000h R/W
000-001
Data Register
ecpAFifo
+000h R/W
011
ECP FIFO (Address)
dsr
+001h R/W
All
Status Register
dcr
+002h R/W
All
Control Register
cFifo
+400h R/W
010
Parallel Port Data FIFO
ecpDFifo
+400h R/W
011
ECP FIFO (DATA)
tFifo
+400h R/W
110
Test FIFO
cnfgA
+400h R
111
Configuration Register A
cnfgB
+401h R/W
111
Configuration Register B
ecr
+402h R/W
All
Extended Control Register
Note 1: These addresses are added to the parallel port base address as selected by configuration
register or jumpers.
Note 2: All addresses are qualified with AEN. Refer to the AEN pin definition.
Table 38 - Mode Descriptions
DESCRIPTION*
MODE
000
SPP mode
001
PS/2 Parallel Port mode
010
Parallel Port Data FIFO mode
011
ECP Parallel Port mode
100
EPP mode (If this option is enabled in the configuration registers)
101
Reserved
110
Test mode
111
Configuration mode
*Refer to ECR Register Description
93
BIT 5 PError
The level on the PError input is read by the CPU
as bit 5 of the Device Status Register. Printer
Status Register.
BIT 6 nAck
The level on the nAck input is read by the CPU
as bit 6 of the Device Status Register.
BIT 7 nBusy
The complement of the level on the BUSY input
is read by the CPU as bit 7 of the Device Status
Register.
DATA and ecpAFifo PORT
ADDRESS OFFSET = 00H
Modes 000 and 001 (Data Port)
The Data Port is located at an offset of '00H'
from the base address. The data register is
cleared at initialization by RESET. During a
WRITE operation, the Data Register latches the
contents of the data bus on the rising edge of
the nIOW input. The contents of this register
are buffered (non inverting) and output onto the
PD0 - PD7 ports. During a READ operation,
PD0 - PD7 ports are read and output to the host
CPU.
DEVICE CONTROL REGISTER (dcr)
ADDRESS OFFSET = 02H
The Control Register is located at an offset of
'02H' from the base address. The Control
Register is initialized to zero by the RESET
input, bits 0 to 5 only being affected; bits 6 and
7 are hard wired low.
BIT 0 STROBE - STROBE
This bit is inverted and output onto the
nSTROBE output.
BIT 1 AUTOFD - AUTOFEED
This bit is inverted and output onto the
nAUTOFD output. A logic 1 causes the printer
to generate a line feed after each line is printed.
A logic 0 means no autofeed.
BIT 2 nINIT - nINITIATE OUTPUT
This bit is output onto the nINIT output without
inversion.
BIT 3 SELECTIN
This bit is inverted and output onto the nSLCTIN
output. A logic 1 on this bit selects the printer; a
logic 0 means the printer is not selected.
BIT 4 ackIntEn - INTERRUPT REQUEST
ENABLE
The interrupt request enable bit when set to a
high level may be used to enable interrupt
requests from the Parallel Port to the CPU due
to a low to high transition on the nACK input.
Refer to the description of the interrupt under
Operation, Interrupts.
Mode 011 (ECP FIFO - Address/RLE)
A data byte written to this address is placed in
the FIFO and tagged as an ECP Address/RLE.
The hardware at the ECP port transmits this
byte to the peripheral automatically.
The
operation of this register is ony defined for the
forward direction (direction is 0). Refer to the
ECP Parallel Port Forward Timing Diagram,
located in the Timing Diagrams section of this
data sheet .
DEVICE STATUS REGISTER (dsr)
ADDRESS OFFSET = 01H
The Status Port is located at an offset of '01H'
from the base address. Bits 0 - 2 are not
implemented as register bits, during a read of
the Printer Status Register these bits are a low
level. The bits of the Status Port are defined as
follows:
BIT 3 nFault
The level on the nFault input is read by the CPU
as bit 3 of the Device Status Register.
BIT 4 Select
The level on the Select input is read by the CPU
as bit 4 of the Device Status Register.
94
Data in the tFIFO will not be transmitted to the
to the parallel port lines using a hardware
protocol handshake.
However, data in the
tFIFO may be displayed on the parallel port data
lines.
BIT 5 DIRECTION
If mode=000 or mode=010, this bit has no effect
and the direction is always out regardless of the
state of this bit. In all other modes, Direction is
valid and a logic 0 means that the printer port is
in output mode (write); a logic 1 means that the
printer port is in input mode (read).
BITS 6 and 7 during a read are a low level, and
cannot be written.
The tFIFO will not stall when overwritten or
underrun. If an attempt is made to write data to
a full tFIFO, the new data is not accepted into
the tFIFO. If an attempt is made to read data
from an empty tFIFO, the last data byte is reread again. The full and empty bits must
always keep track of the correct FIFO state. The
tFIFO will transfer data at the maximum ISA
rate so that software may generate performance
metrics.
cFifo (Parallel Port Data FIFO)
ADDRESS OFFSET = 400h
Mode = 010
Bytes written or DMAed from the system to this
FIFO are transmitted by a hardware handshake
to the peripheral using the standard parallel port
protocol.
Transfers to the FIFO are byte
aligned. This mode is only defined for the
forward direction.
The FIFO size and interrupt threshold can be
determined by writing bytes to the FIFO and
checking the full and serviceIntr bits.
The writeIntrThreshold can be determined by
starting with a full tFIFO, setting the direction bit
to 0 and emptying it a byte at a time until
serviceIntr is set. This may generate a spurious
interrupt, but will indicate that the threshold has
been reached.
ecpDFifo (ECP Data FIFO)
ADDRESS OFFSET = 400H
Mode = 011
Bytes written or DMAed from the system to this
FIFO, when the direction bit is 0, are transmitted
by a hardware handshake to the peripheral
using the ECP parallel port protocol. Transfers
to the FIFO are byte aligned.
The readIntrThreshold can be determined by
setting the direction bit to 1 and filling the empty
tFIFO a byte at a time until serviceIntr is set.
This may generate a spurious interrupt, but will
indicate that the threshold has been reached.
Data bytes from the peripheral are read under
automatic hardware handshake from ECP into
this FIFO when the direction bit is 1. Reads or
DMAs from the FIFO will return bytes of ECP
data to the system.
Data bytes are always read from the head of
tFIFO regardless of the value of the direction bit.
For example if 44h, 33h, 22h is written to the
FIFO, then reading the tFIFO will return 44h,
33h, 22h in the same order as was written.
cnfgA (Configuration Register A)
ADDRESS OFFSET = 400H
Mode = 111
tFifo (Test FIFO Mode)
ADDRESS OFFSET = 400H
Mode = 110
Data bytes may be read, written or DMAed to or
from the system to this FIFO in any direction.
95
This register is a read only register. When read,
10H is returned. This indicates to the system
that this is an 8-bit implementation. (PWord = 1
byte)
BIT 3 dmaEn
Read/Write
1: Enables DMA (DMA starts when serviceIntr
is 0).
0: Disables DMA unconditionally.
BIT 2 serviceIntr
Read/Write
1: Disables DMA and all of the service
interrupts.
0: Enables one of the following 3 cases of
interrupts. Once one of the 3 service
interrupts has occurred serviceIntr bit shall
be set to a 1 by hardware. It must be reset
to 0 to re-enable the interrupts. Writing this
bit to a 1 will not cause an interrupt.
case dmaEn=1:
During DMA (this bit is set to a 1 when
terminal count is reached).
case dmaEn=0 direction=0:
This bit shall be set to 1 whenever there are
writeIntrThreshold or more bytes free in the
FIFO.
case dmaEn=0 direction=1:
This bit shall be set to 1 whenever there are
readIntrThreshold or more valid bytes to be
read from the FIFO.
BIT 1 full
Read only
1: The FIFO cannot accept another byte or the
FIFO is completely full.
0: The FIFO has at least 1 free byte.
BIT 0 empty
Read only
1: The FIFO is completely empty.
0: The FIFO contains at least 1 byte of data.
cnfgB (Configuration Register B)
ADDRESS OFFSET = 401H
Mode = 111
BIT 7 compress
This bit is read only. During a read it is a low
level. This means that this chip does not
support hardware RLE compression. It does
support hardware de-compression!
BIT 6 intrValue
Returns the value on the ISA IRq line to
determine possible conflicts.
BITS [5:3] Parallel Port IRQ (read-only)
Refer to Table 39B.
BITS [2:0] Parallel Port DMA (read-only)
Refer to Table 39C.
ecr (Extended Control Register)
ADDRESS OFFSET = 402H
Mode = all
This register controls the extended ECP parallel
port functions.
BITS 7,6,5
These bits are Read/Write and select the Mode.
BIT 4 nErrIntrEn
Read/Write (Valid only in ECP Mode)
1: Disables the interrupt generated on the
asserting edge of nFault.
0: Enables an interrupt pulse on the high to
low edge of nFault. Note that an interrupt
will be generated if nFault is asserted
(interrupting) and this bit is written from a 1
to a 0. This prevents interrupts from being
lost in the time between the read of the ecr
and the write of the ecr.
96
Table 39A - Extended Control Register
MODE
R/W
000:
Standard Parallel Port Mode . In this mode the FIFO is reset and common collector drivers
are used on the control lines (nStrobe, nAutoFd, nInit and nSelectIn). Setting the direction
bit will not tri-state the output drivers in this mode.
001:
PS/2 Parallel Port Mode. Same as above except that direction may be used to tri-state the
data lines and reading the data register returns the value on the data lines and not the
value in the data register. All drivers have active pull-ups (push-pull).
010:
Parallel Port FIFO Mode. This is the same as 000 except that bytes are written or DMAed to
the FIFO. FIFO data is automatically transmitted using the standard parallel port protocol.
Note that this mode is only useful when direction is 0. All drivers have active pull-ups
(push-pull).
011:
ECP Parallel Port Mode. In the forward direction (direction is 0) bytes placed into the
ecpDFifo and bytes written to the ecpAFifo are placed in a single FIFO and transmitted
automatically to the peripheral using ECP Protocol. In the reverse direction (direction is 1)
bytes are moved from the ECP parallel port and packed into bytes in the ecpDFifo. All
drivers have active pull-ups (push-pull).
100:
Selects EPP Mode: In this mode, EPP is selected if the EPP supported option is selected in
configuration register L3-CRF0. All drivers have active pull-ups (push-pull).
101:
Reserved
110:
Test Mode. In this mode the FIFO may be written and read, but the data will not be
transmitted on the parallel port. All drivers have active pull-ups (push-pull).
111:
Configuration Mode. In this mode the confgA, confgB registers are accessible at 0x400 and
0x401. All drivers have active pull-ups (push-pull).
Table 39B
CONFIG REG B
IRQ SELECTED
BITS 5:3
15
110
Table 39C
CONFIG REG B
DMA SELECTED
BITS 2:0
3
011
14
101
2
010
11
100
1
001
10
011
All Others
000
9
010
7
001
5
111
All Others
000
97
After negotiation, it is necessary to initialize
some of the port bits. The following are required:
OPERATION
Mode Switching/Software Control
•
•
Software will execute P1284 negotiation and all
operation prior to a data transfer phase under
programmed I/O control (mode 000 or 001).
Hardware provides an automatic control line
handshake, moving data between the FIFO and
the ECP port only in the data transfer phase
(modes 011 or 010).
•
•
Set Direction = 0, enabling the drivers.
Set strobe = 0, causing the nStrobe signal
to default to the deasserted state.
Set autoFd = 0, causing the nAutoFd
signal to default to the deasserted state.
Set mode = 011 (ECP Mode)
ECP address/RLE bytes or data bytes may be
sent automatically by writing the ecpAFifo or
ecpDFifo respectively.
Setting the mode to 011 or 010 will cause the
hardware to initiate data transfer.
Note that all FIFO data transfers are byte wide
and byte aligned. Address/RLE transfers are
byte-wide and only allowed in the forward
direction.
If the port is in mode 000 or 001 it may switch to
any other mode. If the port is not in mode 000
or 001 it can only be switched into mode 000 or
001. The direction can only be changed in
mode 001.
The host may switch directions by first switching
to mode = 001, negotiating for the forward or
reverse channel, setting direction to 1 or 0, then
setting mode = 011. When direction is 1 the
hardware shall handshake for each ECP read
data byte and attempt to fill the FIFO. Bytes
may then be read from the ecpDFifo as long as
it is not empty.
Once in an extended forward mode the software
should wait for the FIFO to be empty before
switching back to mode 000 or 001. In this case
all control signals will be deasserted before the
mode switch. In an ecp reverse mode the
software waits for all the data to be read from
the FIFO before changing back to mode 000 or
001. Since the automatic hardware ecp
reverse handshake only cares about the state of
the FIFO it may have acquired extra data which
will be discarded. It may in fact be in the middle
of a transfer when the mode is changed back to
000 or 001. In this case the port will deassert
nAutoFd independent of the state of the transfer.
The design shall not cause glitches on the
handshake signals if the software meets the
constraints above.
ECP transfers may also be accomplished (albeit
slowly) by handshaking individual bytes under
program control in mode = 001, or 000.
Termination from ECP Mode
Termination from ECP Mode is similar to the
termination from Nibble/Byte Modes. The host is
permitted to terminate from ECP Mode only in
specific well-defined states. The termination can
only be executed while the bus is in the forward
direction. To terminate while the channel is in
the reverse direction, it must first be transitioned
into the forward direction.
ECP Operation
Prior to ECP operation the Host must negotiate
on the parallel port to determine if the peripheral
supports
the
ECP protocol. This is a
somewhat complex negotiation carried out
under program control in mode 000.
98
The most significant bit of the command
indicates whether it is a run-length count (for
compression) or a channel address.
Command/Data
ECP Mode supports two advanced features to
improve the effectiveness of the protocol for
some
applications.
The
features
are
implemented by allowing the transfer of normal
8 bit data or 8 bit commands.
When in the reverse direction, normal data is
transferred when PeriphAck is high and an 8 bit
command is transferred when PeriphAck is low.
The most significant bit of the command is
always zero. Reverse channel addresses are
seldom used and may not be supported in
hardware.
When in the forward direction, normal data is
transferred when HostAck is high and an 8 bit
command is transferred when HostAck is low.
99
Table 40 Forward Channel Commands (HostAck Low)
Reverse Channel Commands (PeripAck Low)
D7
D[6:0]
0
Run-Length Count (0-127)
(mode 0011 0X00 only)
1
Channel Address (0-127)
Data Compression
Pin Definition
The ECP port supports run length encoded
(RLE) decompression in hardware and can
transfer compressed data to a peripheral. Run
length encoded (RLE) compression in hardware
is not supported. To transfer compressed data
in ECP mode, the compression count is written
to the ecpAFifo and the data byte is written to
the ecpDFifo.
The drivers for nStrobe, nAutoFd, nInit and
nSelectIn are open-collector in mode 000 and
are push-pull in all other modes.
ISA Connections
The interface can never stall causing the host to
hang. The width of data transfers is strictly
controlled on an I/O address basis per this
specification. All FIFO-DMA transfers are byte
wide, byte aligned and end on a byte boundary.
(The PWord value can be obtained by reading
Configuration Register A, cnfgA, described in
the next section). Single byte wide transfers
are always possible with standard or PS/2 mode
using program control of the control signals.
Compression is accomplished by counting
identical bytes and transmitting an RLE byte
that indicates how many times the next byte is
to be repeated.
Decompression simply
intercepts the RLE byte and repeats the
following byte the specified number of times.
When a run-length count is received from a
peripheral, the subsequent data byte is
replicated the specified number of times. A
run-length count of zero specifies that only one
byte of data is represented by the next data
byte, whereas a run-length count of 127
indicates that the next byte should be expanded
to 128 bytes. To prevent data expansion,
however, run-length counts of zero should be
avoided.
Interrupts
The interrupts are enabled by serviceIntr in the
ecr register.
serviceIntr = 1 Disables the DMA and all of the
service interrupts.
serviceIntr = 0
100
Enables the selected interrupt
condition. If the interrupting
condition is valid, then the
interrupt
is
generated
immediately when this bit is
changed from a 1 to a 0. This
can occur during Programmed
I/O if the number of bytes
removed or added from/to the
FIFO does not cross the
threshold.
FIFO Operation
The FIFO threshold is set in the chip
configuration registers. All data transfers to or
from the parallel port can proceed in DMA or
Programmed I/O (non-DMA) mode as indicated
by the selected mode. The FIFO is used by
selecting the Parallel Port FIFO mode or ECP
Parallel Port Mode. (FIFO test mode will be
addressed separately.) After a reset, the FIFO
is disabled. Each data byte is transferred by a
Programmed I/O cycle or PDRQ depending on
the selection of DMA or Programmed I/O mode.
The interrupt generated is ISA friendly in that it
must pulse the interrupt line low, allowing for
interrupt sharing.
After a brief pulse low
following the interrupt event, the interrupt line is
tri-stated so that other interrupts may assert.
An interrupt is generated when:
1. For DMA transfers: When serviceIntr is 0,
dmaEn is 1 and the DMA TC is received.
The following paragraphs detail the operation of
the FIFO flow control. In these descriptions,
<threshold> ranges from 1 to 16.
The
parameter FIFOTHR, which the user programs,
is one less and ranges from 0 to 15.
2. For Programmed I/O:
a.
When serviceIntr is 0, dmaEn is 0,
direction is 0 and there are
writeIntrThreshold or more free bytes in
the FIFO.
Also, an interrupt is
generated when serviceIntr is cleared
to
0
whenever
there
are
writeIntrThreshold or more free bytes in
the FIFO.
b.(1)
When serviceIntr is 0, dmaEn
is 0, direction is 1 and there
are readIntrThreshold or more
bytes in the FIFO. Also, an
interrupt is generated when
serviceIntr is cleared to 0
whenever
there
are
readIntrThreshold or more
bytes in the FIFO.
A low threshold value (i.e. 2) results in longer
periods of time between service requests, but
requires faster servicing of the request for both
read and write cases. The host must be very
responsive to the service request. This is the
desired case for use with a "fast" system. A
high value of threshold (i.e. 12) is used with a
"sluggish" system by affording a long latency
period after a service request, but results in
more frequent service requests.
DMA TRANSFERS
DMA transfers are always to or from the
ecpDFifo, tFifo or CFifo. DMA utilizes the
standard PC DMA services. To use the DMA
transfers, the host first sets up the direction and
state as in the programmed I/O case. Then it
programs the DMA controller in the host with the
desired count and memory address. Lastly it
sets dmaEn to 1 and serviceIntr to 0. The ECP
requests DMA transfers from the host by
activating the PDRQ pin. The DMA will empty
or fill the FIFO using the appropriate direction
and mode. When the terminal count in the DMA
controller is reached, an interrupt is generated
3. When nErrIntrEn is 0 and nFault transitions
from high to low or when nErrIntrEn is set
from 1 to 0 and nFault is asserted.
4. When ackIntEn is 1 and the nAck signal
transitions from a low to a high.
101
then PDRQ is active again as soon as there is
one byte in the FIFO. If PDRQ goes inactive
due to the TC, then PDRQ is active again when
there is one byte in the FIFO, and serviceIntr
has been re-enabled. (Note: A data underrun
may occur if PDRQ is not removed in time to
prevent an unwanted cycle).
and serviceIntr is asserted, disabling DMA. In
order to prevent possible blocking of refresh
requests dReq shall not be asserted for more
than 32 DMA cycles in a row. The FIFO is
enabled directly by asserting nPDACK and
addresses need not be valid. PINTR is
generated when a TC is received. PDRQ must
not be asserted for more than 32 DMA cycles in
a row. After the 32nd cycle, PDRQ must be
kept unasserted until nPDACK is deasserted for
a minimum of 350nsec. (Note: The only way to
properly terminate DMA transfers is with a TC.)
Programmed I/O Mode or Non-DMA Mode
The ECP or parallel port FIFOs may also be
operated using interrupt driven programmed I/O.
Software can determine the writeIntrThreshold,
readIntrThreshold, and FIFO depth by accessing
the FIFO in Test Mode.
DMA may be disabled in the middle of a transfer
by first disabling the host DMA controller. Then
setting serviceIntr to 1, followed by setting
dmaEn to 0, and waiting for the FIFO to become
empty or full. Restarting the DMA is
accomplished by enabling DMA in the host,
setting dmaEn to 1, followed by setting
serviceIntr to 0.
Programmed I/O transfers are to the ecpDFifo
at 400H and ecpAFifo at 000H or from the
ecpDFifo located at 400H, or to/from the tFifo at
400H. To use the programmed I/O transfers,
the host first sets up the direction and state, sets
dmaEn to 0 and serviceIntr to 0.
DMA Mode - Transfers from the FIFO to the
Host
The ECP requests programmed I/O transfers
from the host by activating the PINTR pin. The
programmed I/O will empty or fill the FIFO using
the appropriate direction and mode.
(Note: In the reverse mode, the peripheral may
not continue to fill the FIFO if it runs out of data
to transfer, even if the chip continues to request
more data from the peripheral.)
Note: A threshold of 16 is equivalent to a
threshold of 15. These two cases are treated
the same.
The ECP activates the PDRQ pin whenever
there is data in the FIFO. The DMA controller
must respond to the request by reading data
from the FIFO. The ECP will deactivate the
PDRQ pin when the FIFO becomes empty or
when the TC becomes true (qualified by
nPDACK), indicating that no more data is
required. PDRQ goes inactive after nPDACK
goes active for the last byte of a data transfer
(or on the active edge of nIOR, on the last byte,
if no edge is present on nPDACK). If PDRQ
goes inactive due to the FIFO going empty,
Programmed I/O - Transfers from the FIFO to
the Host
In the reverse direction an interrupt occurs when
serviceIntr is 0 and readIntrThreshold bytes
are available in the FIFO. If at this time the
FIFO is full it can be emptied completely in a
single burst, otherwise readIntrThreshold bytes
may be read from the FIFO in a single burst.
readIntrThreshold =(16-<threshold>) data bytes
in FIFO
102
the FIFO is empty it can be filled with a single
burst before the empty bit needs to be re-read.
Otherwise
it
may
be
filled
with
writeIntrThreshold bytes.
An interrupt is generated when serviceIntr is 0
and the number of bytes in the FIFO is greater
than or equal to (16-<threshold>). (If the
threshold = 12, then the interrupt is set
whenever there are 4-16 bytes in the FIFO). The
PINT pin can be used for interrupt-driven
systems. The host must respond to the request
by reading data from the FIFO. This process is
repeated until the last byte is transferred out of
the FIFO. If at this time the FIFO is full, it can
be completely emptied in a single burst,
otherwise a minimum of (16-<threshold>) bytes
may be read from the FIFO in a single burst.
writeIntrThreshold =
(16-<threshold>) free
bytes in FIFO
An interrupt is generated when serviceIntr is 0
and the number of bytes in the FIFO is less than
or equal to <threshold>. (If the threshold = 12,
then the interrupt is set whenever there are 12 or
less bytes of data in the FIFO.) The PINT pin
can be used for interrupt-driven systems. The
host must respond to the request by writing data
to the FIFO. If at this time the FIFO is empty, it
can be completely filled in a single burst,
otherwise a minimum of (16-<threshold>) bytes
may be written to the FIFO in a single burst.
This process is repeated until the last byte is
transferred into the FIFO.
Programmed I/O - Transfers from the Host to
the FIFO
In the forward direction an interrupt occurs when
serviceIntr is 0 and there are writeIntrThreshold
or more bytes free in the FIFO. At this time if
103
PARALLEL PORT FLOPPY DISK CONTROLLER
2.
The Floppy Disk Control signals are available
optionally on the parallel port pins. When this
mode is selected, the parallel port is not
available. There are two modes of operation,
PPFD1 and PPFD2. These modes can be
selected in the Parallel Port Mode Register, as
defined in the Parallel Port Mode Register,
Logical Device 3, at 0xF1. PPFD1 has only
drive 1 on the parallel port pins; PPFD2 has
drive 0 and 1 on the parallel port pins.
3.
The following FDC pins are all in the high
impedence state when the PPFDC is actually
selected by the drive select register:
1.
nWDATA, DENSEL, nHDSEL, nWGATE,
nDIR, nSTEP, nDS1, nDS0, nMTR0,
nMTR1.
2.
If PPFDx is selected, then the parallel port
can not be used as a parallel port until
"Normal" mode is selected.
When the PPFDC is selected the following pins
are set as follows:
1.
2.
3.
nPDACK: high-Z
PDRQ: not ECP = high-Z, ECP & dmaEn =
0, ECP & not dmaEn = high-Z
PINTR: not active, this is hi-Z or Low
depending on settings.
The FDC signals are muxed onto the Parallel
Port pins as shown in Table 42.
Note: nPDACK, PDRQ and PINTR refer to the
nDACK, DRQ and IRQ chosen for the parallel
port.
For ACPI compliance the FDD pins that are
multiplexed onto the Parallel Port must function
independently of the state of the Parallel Port
controller. For example, if the FDC is enabled
onto the Parallel Port the multiplexed FDD
interface should function normally regardless of
the Parallel Port Power control, CR22.3. Table
41 illustrates this functionality.
The following parallel port pins are read as
follows by a read of the parallel port register:
1.
Control Register read as "cable not
connected" STROBE, AUTOFD and SLC =
0 and nINIT =1
Status Register reads: nBUSY = 0, PE = 0,
SLCT = 0, nACK = 1, nERR = 1
Data Register (read) = last Data Register
(write)
TABLE 41 - MODIFIED PARALLEL PORT FDD CONTROL
PARALLEL PORT FDC
PARALLEL PORT
PARALLEL PORT
CONTROL
FDC STATE
STATE
LD3:CRF1.1
LD3:CRF1.0
0
0
OFF
ON
0
0
OFF
OFF
1
X
ON
OFF
X
1
(NOTE1)
NOTE1: The Parallel Port Control register reads as “Cable Not Connected” when the Parallel Port
FDC is enabled; i.e., STROBE = AUTOFD = SLC = 0 and nINIT = 1.
PARALLEL
PORT POWER
CR22.3
1
0
X
104
Table 42 - FDC Parallel Port Pins
CONNECTOR
PIN #
1
QFP
CHIP PIN #
83
SPP MODE
nSTROBE
PIN DIRECTION
I/O
FDC MODE
(nDS0)
PIN DIRECTION
I/(O) Note1
2
68
PD0
I/O
nINDEX
I
3
69
PD1
I/O
nTRK0
I
4
70
PD2
I/O
nWP
I
5
71
PD3
I/O
nRDATA
I
6
72
PD4
I/O
nDSKCHG
I
7
73
PD5
I/O
-
8
74
PD6
I/O
(nMTR0)
9
75
PD7
I/O
-
-
10
80
nACK
I
nDS1
O
11
79
BUSY
I
nMTR1
O
12
78
PE
I
nWDATA
O
13
77
SLCT
I
nWGATE
O
14
82
nALF
I/O
DRVDEN0
O
15
81
nERROR
I
nHDSEL
O
16
66
nINIT
I/O
nDIR
O
17
67
nSLCTIN
I/O
nSTEP
O
Note 1: These pins are outputs in mode PPFD2, inputs in mode PPFD1.
105
I/(O) Note1
POWER MANAGEMENT
auto powerdown will once again become
effective.
Power management capabilities are provided for
the following logical devices: floppy disk, UART
1, UART 2 and the parallel port. For each
logical device, two types of power management
are provided; direct powerdown and auto
powerdown.
Wake Up From Auto Powerdown
If the part enters the powerdown state through
the auto powerdown mode, then the part can be
awakened by reset or by appropriate access to
certain registers.
FDC Power Management
Direct power management is controlled by
CR22. Refer to CR22 for more information.
If a hardware or software reset is used then the
part will go through the normal reset sequence.
If the access is through the selected registers,
then the FDC resumes operation as though it
was never in powerdown. Besides activating the
RESET pin or one of the software reset bits in
the DOR or DSR, the following register
accesses will wake up the part:
Auto Power Management is enabled by CR23B0. When set, this bit allows FDC to enter
powerdown when all of the following conditions
have been met:
1.
The motor enable pins of register 3F2H are
inactive (zero).
2.
The part must be idle; MSR=80H and INT =
0 (INT may be high even if MSR = 80H due
to polling interrupts).
3.
The head unload timer must have expired.
4.
The Auto powerdown timer (10msec) must
have timed out.
1.
Enabling any one of the motor enable bits
in the DOR register (reading the DOR does
not awaken the part).
2.
A read from the MSR register.
3.
A read or write to the Data register.
Once awake, the FDC will reinitiate the auto
powerdown timer for 10 ms. The part will
powerdown again when all the powerdown
conditions are satisfied.
An internal timer is initiated as soon as the auto
powerdown command is enabled. The part is
then powered down when all the conditions are
met.
VTR SUPPORT
Disabling the auto powerdown mode cancels the
timer and holds the FDC block out of auto
powerdown.
The FDC37B77x requires a 25 mA trickle supply
(VTR) to provide sleep current for the
programmable wake-up events in the PME
interface when VCC is removed.
If the
FDC37B77x is not intended to provide wake-up
capabilities on standby current, VTR can be
connected to VCC. VTR powers the Consumer IR
receiver, IR interface, the CIR run-time registers,
the PME configuration registers, and the PME
DSR From Powerdown
If DSR powerdown is used when the part is in
auto powerdown, the DSR powerdown will
override the auto powerdown. However, when
the part is awakened from DSR powerdown, the
106
Note: If VTR is to be used for programmable
wake-up events when VCC is removed, VTR must
be at its full minimum potential at least 10 µs
before Vcc begins a power-on cycle. When VTR
and Vcc are fully powered, the potential
difference between the two supplies must not
exceed 500mV.
interface. The VTR pin generates a VTR Poweron-Reset signal to initialize these components.
Internal PWRGOOD
An internal PWRGOOD logical control is
included to minimize the effects of pin-state
uncertainty in the host interface as Vcc cycles on
and off. When the internal PWRGOOD signal is
“1” (active), Vcc is > 3.7V, and the FDC37B77x
host interface is active. When the internal
PWRGOOD signal is “0” (inactive), Vcc is ≤
3.7V, and the FDC37B77x host interface is
inactive; that is, ISA bus reads and writes will
not be decoded.
32.768 kHz TRICKLE CLOCK INPUT
The FDC37B77x utilizes a 32.768 kHz trickle
clock input and a clock multiplier (PLL) to drive
the CIrCC and PME interface when Vcc has been
removed. The PME Power bit, CR22.7, is used
to enable (power-up) the 32.768 kHz trickle
clock PLL. When the PME Power bit is set to
“1” (active), the 32.768 kHz trickle clock PLL is
running and can replace the 14.318 MHz clock
source for the PME Wake Events, depending
upon the state of the internal PWRGOOD signal
(Table 43). When the PME Power bit is reset to
“0” (inactive/default), the 32.768 kHz trickle
clock PLL is unpowered.
The FDC37B77x device pins nPME, CLOCKI32,
KCLK, MCLK, IRRX, nRI1, nRI2 and RXD2 are
part of the PME interface and remain active
when the internal PWRGOOD signal has gone
inactive, provided VTR is powered. The internal
PWRGOOD signal is also used to determine the
clock source for the CIrCC CIR and to disable
the IR Half Duplex Timeout.
PLL CONTROL
(CR24.1)
1
0
0
0
0
TABLE 43 - FDC37B77x PLL CONTROLS AND SELECTS
PME POWER
INTERNAL
(CR22.7)
PWRGOOD
DESCRIPTION
X
X
All PLLs Powered Down
0
0
0
1
32KHz PLL Unpowered, Not Selected,
14MHz PLL Powered, Selected.
1
0
32KHz PLL Powered, Selected,
14MHz PLL Unpowered, Not Selected.
1
1
32KHz PLL Powered, Not Selected, 14MHz PLL
Powered, Selected.
107
Register Behavior
Pin Behavior
Table 44 illustrates the AT and PS/2 (including
Model 30) configuration registers available and
the type of access permitted. In order to
maintain software transparency, access to all
the registers must be maintained. As Table 44
shows, two sets of registers are distinguished
based on whether their access results in the part
remaining in powerdown state or exiting it.
The FDC37B77x is specifically designed for
systems in which power conservation is a
primary concern. This makes the behavior of
the pins during powerdown very important.
The pins of the FDC37B77x can be divided into
two major categories: system interface and
floppy disk drive interface. The floppy disk drive
pins are disabled so that no power will be drawn
through the part as a result of any voltage
applied to the pin within the part's power supply
range. Most of the system interface pins are left
active to monitor system accesses that may
wake up the part.
Access to all other registers is possible without
awakening the part. These registers can be
accessed during powerdown without changing
the status of the part. A read from these
registers will reflect the true status as shown in
the register description in the FDC description. A
write to the part will result in the part retaining
the data and subsequently reflecting it when the
part awakens.
Accessing the part during
powerdown may cause an increase in the power
consumption by the part. The part will revert
back to its low power mode when the access
has been completed.
System Interface Pins
Table 45 gives the state of the system interface
pins in the powerdown state. Pins unaffected by
the powerdown are labeled "Unchanged". Input
pins are "Disabled" to prevent them from
causing currents internal to the FDC37B77x
when they have indeterminate input values.
108
Table 44 - PC/AT and PS/2 Available Registers
AVAILABLE REGISTERS
BASE +
PC-AT
PS/2 (MODEL 30) ACCESS PERMITTED
ADDRESS
Access to these registers DOES NOT wake up the part
00H
----
SRA
R
01H
----
SRB
R
02H
DOR (1)
DOR (1)
R/W
03H
---
---
---
04H
DSR (1)
DSR (1)
W
06H
---
---
---
07H
DIR
DIR
R
CCR
CCR
W
07H
Access to these registers wakes up the part
04H
MSR
MSR
R
05H
Data
Data
R/W
Note 1: Writing to the DOR or DSR does not wake up the part, however, writing any of the
motor enable bits or doing a software reset (via DOR or DSR reset bits) will wake up
the part.
Table 45 - State of System Pins in Auto Powerdown
SYSTEM PINS
STATE IN AUTO POWERDOWN
INPUT PINS
nIOR
Unchanged
nIOW
Unchanged
SA[0:9]
Unchanged
SD[0:7]
Unchanged
RESET_DRV
Unchanged
DACKx
Unchanged
TC
Unchanged
OUTPUT PINS
IRQx
Unchanged (low)
SD[0:7]
Unchanged
DRQx
Unchanged (low)
109
FDD Interface Pins
Pins used for local logic control or part
programming are unaffected. Table 46 depicts
the state of the floppy disk drive interface pins in
the powerdown state.
All pins in the FDD interface which can be
connected directly to the floppy disk drive itself
are either DISABLED or TRISTATED.
Table 46 - State of Floppy Disk Drive Interface Pins in Powerdown
FDD PINS
STATE IN AUTO POWERDOWN
INPUT PINS
nRDATA
Input
nWPROT
Input
nTR0
Input
nINDEX
Input
nDSKCHG
Input
OUTPUT PINS
nMTR0
Tristated
nDS0
Tristated
nDIR
Active
nSTEP
Active
nWDATA
Tristated
nWGATE
Tristated
nHDSEL
Active
DRVDEN[0:1]
Active
110
UART Power Management
Parallel Port
Direct power management is controlled by
CR22. Refer to CR22 for more information.
Direct power management is controlled by
CR22. Refer to CR22 for more information.
Auto Power Management is enabled by CR23B4 and B5. When set, these bits allow the
following auto power management operations:
Auto Power Management is enabled by CR23B3. When set, this bit allows the ECP or EPP
logical parallel port blocks to be placed into
powerdown when not being used.
1.
2.
The transmitter enters auto powerdown
when the transmit buffer and shift register
are empty.
The EPP logic is in powerdown under any of the
following conditions:
The receiver enters powerdown when the
following conditions are all met:
1.
EPP is not enabled in the configuration
registers.
A.
B.
Receive FIFO is empty
The receiver is waiting for a start bit.
2.
EPP is not selected through ecr while in
ECP mode.
While in powerdown the Ring Indicator
interrupt is still valid and transitions
when the RI input changes.
The ECP logic is in powerdown under any of the
following conditions:
Note:
1.
ECP is not enabled in the configuration
registers.
2
SPP, PS/2 Parallel port or EPP mode is
selected through ecr while in ECP mode.
Exit Auto Powerdown
The transmitter exits powerdown on a write to
the XMIT buffer.
The receiver exits auto
powerdown when RXDx changes state.
Exit Auto Powerdown
The parallel port logic can change powerdown
modes when the ECP mode is changed through
the ecr register or when the parallel port mode is
changed through the configuration registers.
111
SERIAL IRQ
The SMI is enabled onto the SMI frame of the Serial IRQ via bit 6 of SMI Enable Register 2.
SERIAL INTERRUPTS
The FDC37B77x will support the serial interrupt to transmit interrupt information to the host system.
The serial interrupt scheme adheres to the Serial IRQ Specification for PCI Systems, Version 6.0.
Timing Diagrams For IRQSER Cycle
PCICLK = 33Mhz_IN pin
IRQSER = SIRQ pin
A) Start Frame timing with source sampled a low pulse on IRQ1
IRQ0 FRAME IRQ1 FRAME IRQ2 FRAME
START FRAME
SL
or
H
H
R
T
S
R
T
S
R
T
S
R
PCICLK
START1
IRQSER
Drive Source
IRQ1
Host Controller
None
H=Host Control
SL=Slave Control
S=Sample
R=Recovery
T=Turn-around
1) Start Frame pulse can be 4-8 clocks wide.
112
IRQ1
None
T
B) Stop Frame Timing with Host using 17 IRQSER sampling period
IRQ14
FRAME
S R T
IRQ15
FRAME
S R T
IOCHCK#
FRAME
S R T
STOP FRAME
I
2
H
R
NEXT CYCLE
T
PCICLK
STOP1
IRQSER
Driver
None
IRQ15
None
H=Host Control
R=Recovery
I= Idle.
1)
2)
3)
START3
Host Controller
T=Turn-around
S=Sample
Stop pulse is 2 clocks wide for Quiet mode, 3 clocks wide for Continuous mode.
There may be none, one or more Idle states during the Stop Frame.
The next IRQSER cycle’s Start Frame pulse may or may not start immediately
after the turn-around clock of the Stop Frame.
113
the IRQSER or the Host Controller can operate
IRQSER in a continuous mode by initiating a
Start Frame at the end of every Stop Frame.
IRQSER Cycle Control
There are two modes of operation for the
IRQSER Start Frame.
An IRQSER mode transition can only occur
during the Stop Frame. Upon reset, IRQSER
bus is defaulted to Continuous mode,
therefore only the Host controller can initiate
the first Start Frame.
Slaves must
continuously sample the Stop Frames pulse
width to determine the next IRQSER Cycle’s
mode.
1) Quiet (Active) Mode: Any device may initiate
a Start Frame by driving the IRQSER low for
one clock, while the IRQSER is Idle. After
driving low for one clock the IRQSER must
immediately be tri-stated without at any time
driving high. A Start Frame may not be initiated
while the IRQSER is Active. The IRQSER is
Idle between Stop and Start Frames. The
IRQSER is Active between Start and Stop
Frames. This mode of operation allows the
IRQSER to be Idle when there are no IRQ/Data
transitions which should be most of the time.
IRQSER Data Frame
Once a Start Frame has been initiated, the
FDC37B77x will watch for the rising edge of the
Start Pulse and start counting IRQ/Data Frames
from there. Each IRQ/Data Frame is three
clocks: Sample phase, Recovery phase, and
Turn-around phase. During the Sample phase
the FDC37B77x must drive the IRQSER (SIRQ
pin) low, if and only if, its last detected IRQ/Data
value was low. If its detected IRQ/Data value is
high, IRQSER must be left tri-stated. During the
Recovery phase the FDC37B77x must drive the
SERIRQ high, if and only if, it had driven the
IRQSER low during the previous Sample Phase.
During the Turn-around Phase the FDC37B77x
must tri-state the SERIRQ. The FDC37B77x will
drive the IRQSER line low at the appropriate
sample point if its associated IRQ/Data line is
low, regardless of which device initiated the
Start Frame.
Once a Start Frame has been initiated the Host
Controller will take over driving the IRQSER low
in the next clock and will continue driving the
IRQSER low for a programmable period of three
to seven clocks. This makes a total low pulse
width of four to eight clocks. Finally, the Host
Controller will drive the IRQSER back high for
one clock, then tri-state.
Any IRQSER Device (i.e., The FDC37B77x)
which detects any transition on an IRQ/Data line
for which it is responsible must initiate a Start
Frame in order to update the Host Controller
unless the IRQSER is already in an IRQSER
Cycle and the IRQ/Data transition can be
delivered in that IRQSER Cycle.
The Sample Phase for each IRQ/Data follows
the low to high transition of the Start Frame
pulse by a number of clocks equal to the
IRQ/Data Frame times three, minus one. (e.g.
The IRQ5 Sample clock is the sixth IRQ/Data
Frame, (6 x 3) - 1 = 17th clock after the rising
edge of the Start Pulse).
2) Continuous (Idle) Mode: Only the Host
controller can initiate a Start Frame to update
IRQ/Data line information. All other IRQSER
agents become passive and may not initiate a
Start Frame. IRQSER will be driven low for four
to eight clocks by Host Controller. This mode
has two functions. It can be used to stop or idle
114
IRQSER PERIOD
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
IRQSER Sampling Periods
SIGNAL SAMPLED
# OF CLOCKS PAST START
Not Used
2
IRQ1
5
nSMI/IRQ2
8
IRQ3
11
IRQ4
14
IRQ5
17
IRQ6
20
IRQ7
23
IRQ8
26
IRQ9
29
IRQ10
32
IRQ11
35
IRQ12
38
IRQ13
41
IRQ14
44
IRQ15
47
The SIRQ data frame will now support IRQ2 from a logical device, previously IRQSER Period 3 was
reserved for use by the System Management Interrupt (nSMI). When using Period 3 for IRQ2 the user
should mask off the SMI via the SMI Enable Register. Likewise, when using Period 3 for nSMI the
user should not configure any logical devices as using IRQ2.
IRQSER Period 14 is used to transfer IRQ13. Logical devices 0 (FDC), 3 (Par Port), 4 (Ser Port 1), 5
(Ser Port 2), 6 (RTC), and 7 (KBD) shall have IRQ13 as a choice for their primary interrupt.
115
followed. This could cause a system fault. The
host interrupt controller is responsible for
ensuring that these latency issues are mitigated.
The recommended solution is to delay EOIs and
ISR Reads to the interrupt controller by the
same amount as the IRQSER Cycle latency in
order to ensure that these events do not occur
out of order.
Stop Cycle Control
Once all IRQ/Data Frames have completed the
Host Controller will terminate IRQSER activity
by initiating a Stop Frame. Only the Host
Controller can initiate the Stop Frame. A Stop
Frame is indicated when the IRQSER is low for
two or three clocks. If the Stop Frame’s low
time is two clocks then the next IRQSER Cycle’s
sampled mode is the Quiet mode; and any
IRQSER device may initiate a Start Frame in
the second clock or more after the rising edge of
the Stop Frame’s pulse. If the Stop Frame’s low
time is three clocks then the next IRQSER
Cycle’s sampled mode is the Continuos mode;
and only the Host Controller may initiate a Start
Frame in the second clock or more after the
rising edge of the Stop Frame’s pulse.
AC/DC Specification Issue
All IRQSER agents must drive / sample
IRQSER synchronously related to the rising
edge of PCI bus clock. IRQSER (SIRQ) pin uses
the electrical specification of PCI bus. Electrical
parameters will follow PCI spec. section 4,
sustained tri-state.
Reset and Initialization
Latency
The IRQSER bus uses RESET_DRV as its reset
signal. The IRQSER pin is tri-stated by all
agents while RESET_DRV is active. With reset,
IRQSER Slaves are put into the (continuous)
IDLE mode. The Host Controller is responsible
for starting the initial IRQSER Cycle to collect
system’s IRQ/Data default values. The system
then follows with the Continuous/Quiet mode
protocol (Stop Frame pulse width) for
subsequent IRQSER Cycles. It is Host
Controller’s responsibility to provide the default
values to 8259’s and other system logic before
the first IRQSER Cycle is performed. For
IRQSER system suspend, insertion, or removal
application, the Host controller should be
programmed into Continuous (IDLE) mode first.
This is to guarantee IRQSER bus is in IDLE
state before the system configuration changes.
Latency for IRQ/Data updates over the IRQSER
bus in bridge-less systems with the minimum
IRQ/Data Frames of seventeen, will range up to
96 clocks (3.84µS with a 25MHz PCI Bus or
2.88uS with a 33MHz PCI Bus). If one or more
PCI to PCI Bridge is added to a system, the
latency for IRQ/Data updates from the
secondary or tertiary buses will be a few clocks
longer
for
synchronous
buses,
and
approximately double for asynchronous buses.
EOI/ISR Read Latency
Any serialized IRQ scheme has a potential
implementation issue related to IRQ latency.
IRQ latency could cause an EOI or ISR Read to
precede an IRQ transition that it should have
116
GP INDEX REGISTERS
To access these registers when in normal (run)
mode, the host should perform an IOW of the
Register Index to the GP Index register (at
0xEX) to select the Register and then read or
write the Data register (at Index+1) to access
the register.
The Watchdog Timer Control, SMI Enable and
SMI Status Registers can be accessed by the
host when the chip is in the normal run mode if
CR03 Bit[7]=1. The host uses GP Index and
Data register to access these registers. The
Power on default GP Index and Data registers
are 0xEA and 0xEB respectively. In
configuration mode the GP Index address may
be programmed to reside on addresses 0xE0,
0xE2, 0xE4 or 0xEA. The GP Data address is
automatically set to the Index address + 1. Upon
exiting the configuration mode the new GP Index
and Data registers are used to access registers
WDT_CTRL, SMI Enable and SMI Status
Registers.
The WDT_CTRL, SMI Enable and SMI Status
registers can also be accessed by the host when
in the configuration state through Logical Device
8.
Table 47A - GP Index and Data Register
REGISTER
ADDRESS (R/W)
NORMAL (RUN) MODE
GP Index
0xE0, E2, E4, EA
0x01-0x0F
GP Data
Index address + 1
Access to Watchdog Timer
Control, SMI Enable and
SMI Status Registers (see
Table 47B)
117
Table 47B - Index and Data Register Normal (Run) Mode
INDEX
NORMAL (RUN) MODE
0x01
Reserved
0x02
Reserved
0x03
Access to Watchdog Timer Control (L8 - CRF4)
0x04
Reserved
0x05
Reserved
0x06
Reserved
0x07
Reserved
0x08
Reserved
0x09
Reserved
0x0A
Reserved
0x0B
Reserved
0x0C
Access to SMI Enable Register 1 (L8-CRB4)
0x0D
Access to SMI Enable Register 2 (L8-CRB5)
0x0E
Access to SMI Status Register 1 (L8-CRB6)
0x0F
Access to SMI Status Register 2 (L8-CRB7)
Note 1:
These registers can also be accessed through the configuration registers at
L8 - CRxx shown in the table above.
118
WATCH DOG TIMER
There are three system events which can reset
the WDT, these are a Keyboard Interrupt, a
Mouse Interrupt, or I/O reads/writes to address
0x201 (the internal or an external Joystick Port).
The effect on the WDT for each of these system
events may be individually enabled or disabled
through bits in the WDT_CFG configuration
register. When a system event is enabled
through the WDT_CFG register, the occurrence
of that event will cause the WDT to reload the
value stored in WDT_VAL and reset the WDT
time-out status bit if set. If all three system
events are disabled the WDT will inevitably time
out.
The FDC37B77x contains a Watch Dog Timer
(WDT). The Watch Dog Time-out status bit may
be mapped to an interrupt through the
WDT_CFG Configuration Register.
The FDC37B77x's WDT has a programmable
time-out ranging from 1 to 255 minutes with one
minute resolution, or 1 to 255 seconds with 1
second resolution.
The units of the WDT
timeout value are selected via bit[7] of the
WDT_TIMEOUT register (LD8:CRF1.7). The
WDT time-out value is set through the
WDT_VAL Configuration register. Setting the
WDT_VAL register to 0x00 disables the WDT
function (this is its power on default). Setting
the WDT_VAL to any other non-zero value will
cause the WDT to reload and begin counting
down from the value loaded. When the WDT
count value reaches zero the counter stops and
sets the Watchdog time-out status bit in the
WDT_CTRL Configuration Register.
Note:
Regardless of the current state of the WDT, the
WDT time-out status bit can be directly set or
cleared by the Host CPU.
The Watch Dog Timer may be configured to
generate an interrupt on the rising edge of the
Time-out status bit. The WDT interrupt is
mapped to an interrupt channel through the
WDT_CFG Configuration Register.
When
mapped to an interrupt the interrupt request pin
reflects the value of the WDT time-out status bit.
The host may force a Watch Dog time-out to
occur by writing a "1" to bit 2 of the WDT_CTRL
(Force WD Time-out) Configuration Register.
Writing a "1" to this bit forces the WDT count
value to zero and sets bit 0 of the WDT_CTRL
(Watch Dog Status). Bit 2 of the WDT_CTRL is
self-clearing.
119
8042 KEYBOARD CONTROLLER DESCRIPTION
The Universal Keyboard Controller uses an
8042 microcontroller CPU core. This section
concentrates on the FDC37B77x enhancements
to the 8042. For general information about the
8042, refer to the "Hardware Description of the
8042" in the 8-Bit Embedded Controller Handbook.
The FDC37B77x is a Super I/O and Universal
Keyboard Controller that is designed for
intelligent keyboard management in desktop
computer applications. The Super I/O supports
a Floppy Disk Controller, two 16550 type serial
ports one ECP/EPP Parallel Port.
8042A
LS05
P27
P10
KDAT
P26
TST0
KCLK
P23
TST1
MCLK
P22
P11
MDAT
Keyboard and Mouse Interface
KIRQ is the Keyboard IRQ
MIRQ is the Mouse IRQ
Port 21 is used to create a GATEA20 signal from the FDC37B77x.
120
Output Data register. Table 48 shows how the
interface decodes the control signals.
In
addition to the above signals, the host interface
includes keyboard and mouse IRQs.
KEYBOARD ISA INTERFACE
The FDC37B77x ISA interface is functionally
compatible with the 8042 style host interface. It
consists of the D0-7 data bus; the nIOR, nIOW
and the Status register, Input Data register, and
Table 48 - ISA I/O Address Map
nIOR
BLOCK
FUNCTION (NOTE 1)
ISA ADDRESS
nIOW
0x60
0
1
KDATA
Keyboard Data Write (C/D=0)
1
0
KDATA
Keyboard Data Read
0
1
KDCTL
Keyboard Command Write (C/D=1)
1
0
KDCTL
Keyboard Status Read
0x64
Note 1: These registers consist of three separate 8 bit registers. Status, Data/Command Write and
Data Read.
Keyboard Data Write
Keyboard Command Write
This is an 8 bit write only register. When
written, the C/D status bit of the status register
is cleared to zero and the IBF bit is set.
This is an 8 bit write only register. When
written, the C/D status bit of the status register
is set to one and the IBF bit is set.
Keyboard Data Read
Keyboard Status Read
This is an 8 bit read only register. If enabled by
"ENABLE FLAGS", when read, the KIRQ output
is cleared and the OBF flag in the status register
is cleared. If not enabled, the KIRQ and/or
AUXOBF1 must be cleared in software.
This is an 8 bit read only register. Refer to the
description of the Status Register for more
information.
121
CPU-to-Host Communication
to this register automatically sets Bit 0 (OBF) in
the Status register. See Table 49.
The FDC37B77x CPU can write to the Output
Data register
via
register DBB. A write
8042 INSTRUCTION
OUT DBB
Table 49 - Host Interface Flags
FLAG
Set OBF, and, if enabled, the KIRQ output signal goes high
MIRQ
If "EN FLAGS" has been executed and P25 is
set to a one:; IBF is inverted and gated onto
MIRQ. The MIRQ signal can be connected to
system interrupt to signify that the FDC37B77x
CPU has read the DBB register.
Host-to-CPU Communication
The host system can send both commands and
data to the Input Data register. The CPU
differentiates between commands and data by
reading the value of Bit 3 of the Status register.
When bit 3 is "1", the CPU interprets the register
contents as a command. When bit 3 is "0", the
CPU interprets the register contents as data.
During a host write operation, bit 3 is set to "1" if
SA2 = 1 or reset to "0" if SA2 = 0.
If "EN FLAGS” has not been executed, MIRQ is
controlled by P25, Writing a zero to P25 forces
MIRQ low, a high forces MIRQ high. (MIRQ is
normally selected as IRQ12 for mouse support).
KIRQ
If "EN FLAGS" has been executed and P24 is
set to a one: the OBF flag is gated onto KIRQ.
The KIRQ signal can be connected to system
interrupt to signify that the FDC37B77x CPU has
written to the output data register via "OUT
DBB,A". If P24 is set to a zero, KIRQ is forced
low. On power-up, after a valid RST pulse has
been delivered to the device, KIRQ is reset to 0.
KIRQ will normally reflects the status of writes
"DBB". (KIRQ is normally selected as IRQ1 for
keyboard support.)
Gate A20
A general purpose P21 is used as a software
controlled Gate A20 or user defined output.
EXTERNAL
KEYBOARD
AND
MOUSE
INTERFACE
Industry-standard PC-AT-compatible keyboards
employ a two-wire, bidirectional TTL interface
for data transmission. Several sources also
supply PS/2 mouse products that employ the
same type of interface. To facilitate system
expansion, the FDC37B77x provides four signal
pins that may be used to implement this
interface directly for an external keyboard and
mouse.
If "EN FLAGS” has not been executed: KIRQ
can be controlled by writing to P24. Writing a
zero to P24 forces KIRQ low; a high forces
KIRQ high.
122
The FDC37B77x has four high-drive, open-drain
output, bidirectional port pins that can be used for
external serial interfaces, such as ISA external
keyboard and PS/2-type mouse interfaces. They are
KCLK, KDAT, MCLK, and MDAT. P26 is inverted and
output as KCLK. The KCLK pin is connected to
TEST0. P27 is inverted and output as KDAT. The
KDAT pin is connected to P10. P23 is inverted and
output as MCLK. The MCLK pin is connected to
TEST1. P22 is inverted and output as MDAT. The
MDAT pin is connected to P11. NOTE: External pullups may be required.
Hard Power Down Mode
This mode is entered by executing a STOP
instruction. The oscillator is stopped by disabling the
oscillator driver
cell. When either RESET is
driven active or a data byte is written to the DBBIN
register by a master CPU, this mode will be exited (as
above). However, as the oscillator cell will require an
initialization time, either RESET must be held active
for sufficient time to allow the oscillator to stabilize.
Program execution will resume as above.
INTERRUPTS
KEYBOARD POWER MANAGEMENT
The FDC37B77x provides the two 8042 interrupts.
IBF and the Timer/Counter Overflow.
The keyboard provides support for two power-saving
modes: soft powerdown mode and hard powerdown
mode. In soft powerdown mode, the clock to the ALU
is stopped but the timer/counter and interrupts are still
active. In hard power down mode the clock to the
8042 is stopped.
MEMORY CONFIGURATIONS
The FDC37B77x provides 2K of on-chip ROM and
256 bytes of on-chip RAM.
Soft Power Down Mode
Register Definitions
This mode is entered by executing a HALT
instruction. The execution of program code is halted
until either RESET is driven active or a data byte is
written to the DBBIN register by a master CPU. If
this mode is exited using the interrupt, and the IBF
interrupt is enabled, then program execution resumes
with a CALL to the interrupt routine, otherwise the
next instruction is executed. If it is exited using
RESET then a normal reset sequence is initiated and
program execution starts from program memory
location 0.
Host I/F Data Register
The Input Data register and Output Data register are
each 8 bits wide. A write to this 8 bit register will load
the Keyboard Data Read Buffer, set the OBF flag and
set the KIRQ output if enabled. A read of this register
will read the data from the Keyboard Data or
Command Write Buffer and clear the IBF flag. Refer
to the KIRQ and Status register descriptions for more
information.
Host I/F Status Register
The Status register is 8 bits wide. Table 50 shows
the contents of the Status register.
D7
D6
D5
Table 50 - Status Register
D4
D3
D2
D1
D0
UD
UD
UD
UD
IBF
OBF
C/D
123
UD
cleared.
There is no output pin
associated with this internal signal.
Status Register
This register is cleared on a reset. This register
is read-only for the Host and read/write by the
FDC37B77x CPU.
UD
Writable by FDC37B77x CPU. These
bits are user-definable.
C/D
(Command Data)-This bit specifies
whether the input data register contains
data or a command (0 = data, 1 =
command).
During
a
host
data/command write operation, this bit
is set to "1" if SA2 = 1 or reset to "0" if
SA2 = 0.
IBF
OBF
EXTERNAL CLOCK SIGNAL
The FDC37B77x Keyboard Controller clock
source is a 12 MHz clock generated from a
14.318 MHz clock. The reset pulse must last for
at least 24 16 MHz clock periods. The pulsewidth requirement applies to both internally (Vcc
POR) and externally generated reset signals. In
powerdown mode, the external clock signal is
not loaded by the chip.
(Input Buffer Full)- This flag is set to 1
whenever the host system writes data
into the input data register. Setting this
flag activates the FDC37B77x CPU's
nIBF (MIRQ) interrupt if enabled. When
the FDC37B77x CPU reads the input
data register (DBB), this bit is
automatically reset and the interrupt is
DESCRIPTION
(Output Buffer Full) - This flag is set to
whenever the FDC37B77x CPU write to
the output data register (DBB). When
the host system reads the output data
register, this bit is automatically reset.
DEFAULT RESET CONDITIONS
The FDC37B77x has one source of reset: an
external reset via the RESET_DRV pin. Refer to
Table 51 for the effect of each type of reset on
the internal registers.
Table 51 - Resets
HARDWARE RESET (RESET)
KCLK
Input
KDAT
MCLK
MDAT
Input
Input
Input
N/A
00H
Host I/F Data Reg
Host I/F Status Reg
N/A: Not Applicable
124
has been enabled via bit 2 of the KRST_GA20
Register (Logical Device 7, 0xF0) set to 1.
GATEA20 AND KEYBOARD RESET
The FDC37B77x provides two options for
GateA20 and Keyboard Reset: 8042 Software
Generated GateA20 and KRESET and Port 92
Fast GateA20 and KRESET.
This register is used to support the alternate
reset (nALT_RST) and alternate A20 (ALT_A20)
functions.
PORT 92 FAST GATEA20 AND KEYBOARD
RESET
Name
Location
Default Value
Attribute
Size
Port 92 Register
This port can only be read or written if Port 92
Bit
7:6
5
4
3
2
1
0
Port 92
92h
24h
Read/Write
8 bits
Port 92 Register
Function
Reserved. Returns 00 when read
Reserved. Returns a 1 when read
Reserved. Returns a 0 when read
Reserved. Returns a 0 when read
Reserved. Returns a 1 when read
ALT_A20 Signal control. Writing a 0 to this bit causes the ALT_A20 signal to be
driven low. Writing a 1 to this bit causes the ALT_A20 signal to be driven high.
Alternate System Reset. This read/write bit provides an alternate system reset
function. This function provides an alternate means to reset the system CPU to
effect a mode switch from Protected Virtual Address Mode to the Real Address
Mode. This provides a faster means of reset than is provided by the Keyboard
controller. This bit is set to a 0 by a system reset. Writing a 1 to this bit will cause
the nALT_RST signal to pulse active (low) for a minimum of 1 µs after a delay of
500 ns. Before another nALT_RST pulse can be generated, this bit must be
written back to a 0.
nGATEA20
8042
P21
0
0
1
1
ALT_A20
0
1
0
1
125
System
nA20M
0
1
1
1
pulse can be generated, bit 0 must be set to 0
either by a system reset of a write to Port 92.
Upon reset, this signal is driven inactive high (bit
0 in the Port 92 Register is set to 0).
Bit 0 of Port 92, which generates the nALT_RST
signal, is used to reset the CPU under program
control.
This signal is AND’ed together
externally with the reset signal (nKBDRST) from
the keyboard controller to provide a software
means of resetting the CPU. This provides a
faster means of reset than is provided by the
keyboard controller. Writing a 1 to bit 0 in the
Port 92 Register causes this signal to pulse low
for a minimum of 6µs, after a delay of a
minimum of 14µs. Before another nALT_RST
If Port 92 is enabled, i.e., bit 2 of KRST_GA20 is
set to 1, then a pulse is generated by writing a 1
to bit 0 of the Port 92 Register and this pulse is
AND’ed with the pulse generated from the 8042.
This pulse is output on pin KRESET and its
polarity is controlled by the GPI/O polarity
configuration.
14us
~
~
6us
8042
P20
KRST
KBDRST
KRST_GA20
Bit 2
P92
nALT_RST
Bit 0
Pulse
Gen
14us
~
~
Note: When Port 92 is disabled,
writes are ignored and reads
return undefined values.
6us
KRESET Generation
126
for all timing. A port signal of 0 drives the
output to 0. A port signal of 1 causes the port
enable signal to drive the output to 1 within 2030nsec. After several (# TBD) clocks, the port
enable goes away and the internal 90µA pull-up
maintains the output signal as 1.
Bit 1 of Port 92, the ALT_A20 signal, is used to
force nA20M to the CPU low for support of real
mode compatible software.
This signal is
externally OR’ed with the A20GATE signal from
the keyboard controller and CPURST to control
the nA20M input of the CPU. Writing a 0 to bit 1
of the Port 92 Register forces ALT_A20 low.
ALT_A20 low drives nA20M to the CPU low, if
A20GATE from the keyboard controller is also
low. Writing a 1 to bit 1 of the Port 92 Register
forces ALT_A20 high. ALT_A20 high drives
nA20M to the CPU high, regardless of the state
of A20GATE from the keyboard controller.
Upon reset, this signal is driven low.
In 8042 mode, the pins can be programmed as
open drain. When programmed in open drain
mode, the port enables do not come into play. If
the port signal is 0 the output will be 0. If the
port signal is 1, the output tristates: an external
pull-up can pull the pin high, and the pin can be
shared i.e., P12 and nSMI can be externally tied
together. In 8042 mode, the pins cannot be
programmed as input nor inverted through the
GP configuration registers.
8042 P12 and P16 Functions
8042 functions P12 and P16 are implemented
as in a true 8042 part. Reference the 8042 spec
127
0ns
250ns
500ns
CLK
AEN
nAEN
64=I/O Addr
n64
nIOW
nA
DD1
nDD1
nCNTL
nIOW'
nIOW+n64
AfterD1
nAfterD1
60=I/O Addr
n60
nIOW+n60=B
nAfterD1+B
D[1]
GA20
Gate A20 Turn-On Sequence Timing
When writing to the command and data port
with hardware speedup, the IOW timing shown
in the figure titled “IOW Timing for Port 92” in
the Timing Diagrams Section is used. This
setup time is only required to be met when using
hardware speedup; the data must be valid a
minimum of 0 nsec from the leading edge of the
write and held throughout the entire write cycle.
128
SYSTEM MANAGEMENT INTERRUPT (SMI)
The FDC37B77x implements a group nSMI
output pin. The System Management Interrupt
is a non-maskable interrupt with the highest
priority level used for transparent power
management. The nSMI group interrupt output
consists of the enabled interrupts from each of
the functional blocks in the chip. The interrupts
are enabled onto the group nSMI output via the
SMI Enable Registers 1 and 2. The nSMI output
is then enabled onto the group nSMI output pin
via bit[7] in the SMI Enable Register 2.
The logic equation for the nSMI output is
follows:
nSMI = (EN_PINT and IRQ_PINT)
(EN_U2INT and IRQ_U2INT)
(EN_U1INT and IRQ_U1INT)
(EN_FINT
and
IRQ_FINT)
(EN_WDT
and
IRQ_WDT)
(EN_MINT
and
IRQ_MINT)
(EN_KINT
and
IRQ_KINT)
(EN_IRINT and IRQ_IRINT)
This register is used to enable additional
interrupt sources onto the group nSMI output.
This register is also used to enable the group
nSMI output onto the nSMI Serial/Parallel IRQ
pin and the routing of 8042 P12 internally to
nSMI.
SMI Status Registers
SMI Status Register 1
(Configuration Register B6, Logical Device 8)
This register is used to read the status of the
SMI input events. Note: The status bit gets set
whether or not the interrupt is enabled onto the
group SMI output.
as
or
or
or
or
or
or
or
SMI Status Register 2
(Configuration Register B7, Logical Device 8)
PME SUPPORT
The FDC37B77x offers support for PCI power
management events (PMEs).
A power
management event is requested by a PCI
function via the assertion of the nPME signal.
The assertion and deassertion of nPME is
asynchronous to the PCI clock.
In the
FDC37B77x, only active transitions on the ring
indicator inputs nRI1 and nRI2, valid NEC
infrared remote control frames, active keyboardclock edges and active mouse-clock edges can
assert the nPME signal. Note: The keyboarddata and mouse-data pins are inactive (tri-state)
when VCC = 0V and VTR = 5V
REGISTERS
The following registers can be accessed when in
configuration mode at Logical Device 8,
Registers B4-B7 and when not in configuration
they can be accessed through the Index and
Data Register (refer to Table 49B).
SMI Enable Registers
SMI Enable Register 1
(Configuration Register B4, Logical Device 8)
This register is used to enable the different
interrupt sources onto the group nSMI output.
nPME functionality is controlled by the
configuration registers in logical device number
eight.
The PME Enable bit, PME_En,
LD8:CRC5.0, globally controls PME Wake-up
events. When PME_En is inactive, the nPME
signal can not be asserted. When PME_En is
asserted, any wake source whose individual
SMI Enable Register 2
(Configuration Register B5, Logical Device 8)
129
PME_Status, LD8:CR6.0, is asserted by active
transitions of PME Wake sources. PME_Status
will become asserted independent of the state of
the global PME enable, PME_En. Refer to the
CONFIGURATION section for further details.
PME Wake Enable register bit, LD8:CRC8, is
asserted can cause nPME to become asserted.
The PME Wake Status register, LD8:CRC7,
indicates which wake source has asserted the
nPME
signal.
The
PME
Status
bit,
130
CONFIGURATION
configuration ports to initialize the logical
devices at POST. The INDEX and DATA ports
are only valid when the FDC37B77x is in
Configuration Mode.
The Configuration of the FDC37B77x is very
flexible and is based on the configuration
architecture implemented in typical Plug-andPlay components. The FDC37B77x is designed
for motherboard applications in which the
resources required by their components are
known. With its flexible resource allocation
architecture, the FDC37B77x allows the BIOS to
assign resources at POST.
The SYSOPT pin is latched on the falling edge
of the RESET_DRV or on Vcc Power On Reset
to determine the configuration register's base
address. The SYSOPT pin is used to select the
CONFIG PORT's I/O address at power-up.
Once powered up the configuration port base
address can be changed through configuration
registers CR26 and CR27. The SYSOPT pin is
a hardware configuration pin which is shared
with the nRTS1 signal on pin 87. During reset
this pin is a weak active low signal which sinks
30µA. Note: All I/O addresses are qualified with
AEN.
SYSTEM ELEMENTS
Primary Configuration Address Decoder
After a hard reset (RESET_DRV pin asserted) or
Vcc Power On Reset the FDC37B77x is in the
Run Mode with all logical devices disabled. The
logical devices may be configured through two
standard Configuration I/O Ports (INDEX and
DATA) by placing the FDC37B77x into
Configuration Mode. The BIOS uses these
PORT NAME
CONFIG PORT (Note
2)
SYSOPT= 0
PULL-DOWN RESISTOR
(NOTE 1)
0x03F0
SYSOPT= 1
10K PULL-UP
RESISTOR
0x0370
TYPE
Write
0x03F0
0x0370
Read/Write
INDEX PORT (Note 2)
DATA PORT
Note 1:
Note 2:
The INDEX and DATA ports are effective only
when the chip is in the Configuration State.
INDEX PORT + 1
Read/Write
If using TTL RS232 drivers use 1K pull-down. If using CMOS RS232 drivers use
10K pull-down.
The configuration port base address can be relocated through CR26 and CR27.
Entering the Configuration State
Exiting the Configuration State
The device enters the Configuration State when
the following Config Key is successfully written
to the CONFIG PORT.
The device exits the Configuration State when
the following Config Key is successfully written
to the CONFIG PORT.
Config Key = < 0x55 >
Config Key = < 0xAA>
131
Exit Configuration Mode
To exit the Configuration State the system writes
0xAA to the CONFIG PORT. The chip returns
to the RUN State.
CONFIGURATION SEQUENCE
To program the configuration registers, the
following sequence must be followed:
1. Enter Configuration Mode
2. Configure the Configuration Registers
3. Exit Configuration Mode.
Note: Only two states are defined (Run and
Configuration). In the Run State the chip will
always be ready to enter the Configuration
State.
Enter Configuration Mode
To place the chip into the Configuration State
the Config Key is sent to the chip's CONFIG
PORT. The config key consists of 0x55 written
to the CONFIG PORT. Once the configuration
key is received correctly the chip enters into the
Configuration State (The auto Config ports are
enabled).
Programming Example
The following is an example of a configuration
program in Intel 8086 assembly language.
;----------------------------.
; ENTER CONFIGURATION MODE
|
;----------------------------'
MOV
DX,3F0H
MOV
AX,055H
OUT
DX,AL
;----------------------------.
; CONFIGURE REGISTER CRE0,
|
; LOGICAL DEVICE 8
|
;----------------------------'
MOV
DX,3F0H
MOV
AL,07H
OUT
DX,AL ;Point to LD# Config
Reg
MOV
DX,3F1H
MOV
AL, 08H
Configuration Mode
The system sets the logical device information
and activates desired logical devices through
the INDEX and DATA ports. In configuration
mode, the INDEX PORT is located at the
CONFIG PORT address and the DATA PORT is
at INDEX PORT address + 1.
The desired configuration registers are accessed
in two steps:
a. Write the index of the Logical Device
Number Configuration Register (i.e., 0x07) to
the INDEX PORT and then write the number
of the desired logical device to the DATA
PORT
b. Write the address of the desired
configuration register within the logical
device to the INDEX PORT and then write or
read the configuration register through the
DATA PORT.
OUT
DX,AL;Point to Logical Device 8
;
MOV
DX,3F0H
MOV
AL,E0H
OUT
DX,AL ; Point to CRE0
MOV
DX,3F1H
MOV
AL,02H
OUT
DX,AL ; Update CRE0
;-----------------------------.
; EXIT CONFIGURATION MODE
|
;-----------------------------'
MOV
DX,3F0H
MOV
AX,0AAH
OUT
DX,AL
Note: If accessing the Global Configuration
Registers, step (a) is not required.
132
Notes: HARD RESET: RESET_DRV pin asserted
SOFT RESET: Bit 0 of Configuration Control register set to one
All host accesses are blocked for 500µs after Vcc POR (see Power-up Timing Diagram)
INDEX
Table 52 – FDC37B77x Configuration Registers Summary
HARD
VCC
SOFT
VTR
RESET
POR
RESET
POR
TYPE
CONFIGURATION REGISTER
GLOBAL CONFIGURATION REGISTERS
0x02
W
0x00
0x00
-
0x00
Configuration Control
0x03
R/W
0x03
0x03
-
0x03
Index Address
0x07
R/W
0x00
0x00
0x00
0x00
Logical Device Number
0x20
R
0x43
Device ID - hard wired
0x21
R
0x22
R/W
0x00
Current Revision
0x00
0x00
0x00
0x23
R/W
0x00
0x00
-
0x00
0x24
R/W
0x04
0x04
-
0x04
0x26
R/W
-
-
Configuration Port Address Byte 0
-
-
Configuration Port Address Byte 1
Sysop
Sysop
=0: 0xF0 =0: 0xF0
Device Rev - hard wired
Power Control3
POWER MGMT
OSC
Sysop
Sysop
=1: 0x70 =1: 0x70
0x27
R/W
Sysop
Sysop
=0: 0x03 =0: 0x03
Sysop
Sysop
=1: 0x03 =1: 0x03
0x2B
R/W
-
0x00
-
0x00
TEST 4
0x2C
R/W
-
0x00
-
0x00
TEST 5
0x2D
R/W
-
0x00
-
0x00
TEST 1
0x2E
R/W
-
0x00
-
0x00
TEST 2
0x2F
R/W
-
0x00
-
0x00
TEST 3
LOGICAL DEVICE 0 CONFIGURATION REGISTERS (FDD)
0x30
R/W
0x00
0x00
0x00
0x00
Activate
0x60,
R/W
0x03,
0x03,
0x03,
0x03,
Primary Base I/O Address
0x61
0xF0
0xF0
0xF0
0xF0
0x70
R/W
0x06
0x06
0x06
0x06
Primary Interrupt Select
0x74
R/W
0x02
0x02
0x02
0x02
DMA Channel Select
133
INDEX
TYPE
HARD
RESET
VCC
POR
SOFT
RESET
VTR
POR
0xF0
R/W
0x0E
0x0E
-
0x0E
FDD Mode Register
0xF1
R/W
0x00
0x00
-
0x00
FDD Option Register
0xF2
R/W
0xFF
0xFF
-
0xFF
FDD Type Register
0xF4
R/W
0x00
0x00
-
0x00
FDD0
0xF5
R/W
0x00
0x00
-
0x00
FDD1
CONFIGURATION REGISTER
LOGICAL DEVICE 1 CONFIGURATION REGISTERS (RESERVED)
LOGICAL DEVICE 2 CONFIGURATION REGISTERS (RESERVED)
LOGICAL DEVICE 3 CONFIGURATION REGISTERS (Parallel Port)
0x30
R/W
0x00
0x00
0x00
0x00
Activate
0x60,
R/W
0x00,
0x00,
0x00,
0x00,
Primary Base I/O Address
0x00
0x00
0x00
0x00
0x00
0x00
0x00
0x00
0x61
0x70
R/W
Primary Interrupt Select
0x74
R/W
0x04
0x04
0x04
0x04
DMA Channel Select
0xF0
R/W
0x3C
0x3C
-
0x3C
Parallel Port Mode Register
0xF1
R/W
0x00
0x00
-
0x00
Parallel Port Mode Register 2
LOGICAL DEVICE 4 CONFIGURATION REGISTERS (Serial Port 1)
0x30
R/W
0x00
0x00
0x00
0x00
Activate
0x60,
R/W
0x00,
0x00,
0x00,
0x00,
Primary Base I/O Address
0x00
0x00
0x00
0x00
0x61
0x70
R/W
0x00
0x00
0x00
0x00
Primary Interrupt Select
0xF0
R/W
0x00
0x00
-
0x00
Serial Port 1 Mode Register
0x30
R/W
-
-
-
0x00
Activate
0x60,
R/W
0x00,
0x00,
0x00,
0x00,
Primary Base I/O Address
0x00
0x00
0x00
0x00
R/W
0x00,
0x00,
0x00,
0x00,
0x00
0x00
0x00
0x00
0x00
0x00
0x00
0x00
Primary Interrupt Select
LOGICAL DEVICE 5 CONFIGURATION REGISTERS (Serial Port 2)
0x61
0x62,
0x63
0x70
R/W
CIrCC Base I/O Address
0x74
R/W
0x04
0x04
0x04
0x04
DMA Channel Select
0xF0
R/W
0x00
0x00
-
0x00
Serial Port 2 Mode Register
134
INDEX
TYPE
HARD
RESET
VCC
POR
SOFT
RESET
VTR
POR
0xF1
R/W
0x02
0x02
-
0x02
IR Options Register
0xF2
R/W
0x03
0x03
-
0x03
IR Half Duplex Timeout
CONFIGURATION REGISTER
LOGICAL DEVICE 6 CONFIGURATION REGISTERS (RESERVED)
LOGICAL DEVICE 7 CONFIGURATION REGISTERS (KEYBOARD)
0x30
R/W
0x00
0x00
0x00
0x00
Activate
0x70
R/W
0x00
0x00
0x00
0x00
Primary Interrupt Select
0x72
R/W
0x00
0x00
0x00
0x00
Second Interrupt Select
0xF0
R/W
0x00
0x00
0x00
KRESET and GateA20 Select
LOGICAL DEVICE 8 CONFIGURATION REGISTERS (Aux I/O)
0x30
R/W
0x00
0x00
0x00
0x00
Activate
0xB4
R/W
-
0x00
-
0x00
SMI Enable Register 1
0xB5
R/W
-
0x00
-
0x00
SMI Enable Register 2
0xB6
R/W
-
0x00
-
0x00
SMI Status Register 1
0xB7
R/W
-
0x00
-
0x00
SMI Status Register 2
0xC0
R/W
0x02
0x02
-
0x02
Pin Multiplex Controls
0xC1
R/W
0x01
0x01
-
0x01
Force Disk Change
0xC2
R
-
-
-
-
Floppy Data Rate Select Shadow
0xC3
R
-
-
-
-
UART1 FIFO Control Shadow
0xC4
R
-
-
-
-
UART2 FIFO Control Shadow
0xC5
R/W
-
-
-
0x00
PME Control Register
0xC6
R/WCLEAR
-
-
-
0x00
PME Status Register
0xC7
R/WCLEAR
-
-
-
0x00
PME Wake Status Register
0xC8
R/W
-
-
-
0x00
PME Wake Enable Register
0xF1
R/W
0x00
0x00
-
0x00
WDT_TIME_OUT
0xF2
R/W
0x00
0x00
-
0x00
WDT_VAL
0xF3
R/W
0x00
0x00
-
0x00
WDT_CFG
2
0x00
-
0x00
WDT_CTRL
0xF4
R/W
1
0x00
135
INDEX
TYPE
0xF6 :
FB
Note 1:
Note 2:
Note 3:
HARD
RESET
VCC
POR
SOFT
RESET
VTR
POR
-
-
-
-
CONFIGURATION REGISTER
Reserved
This register contains some bits that are read or write only.
Bit 0 is not cleared by HARD RESET.
CR22 bit 5 and bit 7 are reset by VTR POR, only.
Chip Level (Global) Control/Configuration
Registers[0x00-0x2F]
The INDEX PORT is used to select a
configuration register in the chip. The DATA
PORT is then used to access the selected
register. These registers are accessible only in
the Configuration Mode.
The chip-level (global) registers lie in the
address range [0x00-0x2F]. The design MUST
use all 8 bits of the ADDRESS Port for register
selection. All unimplemented registers and bits
ignore writes and return zero when read.
Table 53 - Chip Level Registers
REGISTER
ADDRESS
DESCRIPTION
STATE
Chip (Global) Control Registers
0x00 0x01
Config Control
Default = 0x00
on Vcc POR or
Reset_Drv
0x02 W
Reserved - Writes are ignored, reads return 0.
The hardware automatically clears this bit after the
write, there is no need for software to clear the bits.
Bit 0 = 1: Soft Reset. Refer to the "Configuration
Registers" table for the soft reset value for each
register.
136
C
Table 53 - Chip Level Registers
REGISTER
Index Address
ADDRESS
0x03 R/W
DESCRIPTION
Bit[7]
=1
Default = 0x03
=0
on Vcc POR or
Reset_Drv
STATE
Enable WDT_CTRL and SMI Enable and
SMI Status Register access when not in
configuration mode
Disable WDT_CTRL and SMI Enable and
SMI Status Register access when not in
configuration mode (Default)
Bits [6:2]
Reserved - Writes are ignored, reads return 0.
Bits[1:0]
Sets GP index register address when in Run mode
(not in Configuration Mode).
= 11 0xEA (Default)
= 10 0xE4
= 01 0xE2
= 00 0xE0
0x04 - 0x06 Reserved - Writes are ignored, reads return 0.
Logical Device #
0x07 R/W
Default = 0x00
on Vcc POR or
Reset_Drv
Card Level
Reserved
A write to this register selects the current logical
device. This allows access to the control and
configuration registers for each logical device.
Note: The Activate command operates only on the
selected logical device.
C
0x08 - 0x1F Reserved - Writes are ignored, reads return 0.
Chip Level, SMSC Defined
Device ID
0x20 R
A read only register which provides device
identification. Bits[7:0] = 0x43 when read.
C
0x21 R
A read only register which provides device revision
information. Bits[7:0] = current revision when read.
C
Hard wired
= 0x43
Device Rev
Hard wired
= Current Revision
137
Table 53 - Chip Level Registers
REGISTER
PowerControl
ADDRESS
DESCRIPTION
STATE
0x22 R/W
Bit[0] FDC Power
Bit[1] Reserved
Bit[2] Reserved
Bit[3] Parallel Port Power
Bit[4] Serial Port 1 Power
Bit[5] Serial Port 2 Power (Note 1)
Bit[6] Reserved
Bit[7] PME Power (Note 1)
=0
Trickle Clock Inactive (default)
=1
Trickle Clock Running. PLL selected by
internal PWRGOOD signal.
C
0x23 R/W
Bit[0] FDC
Bit[1] Reserved
Bit[2] Reserved
Bit[3] Parallel Port
Bit[4] Serial Port 1
Bit[5] Serial Port 2
Bit[6:7] Reserved (read as 0)
=0
Intelligent Pwr Mgmt off
=1
Intelligent Pwr Mgmt on
C
Default = 0x00.
on Vcc POR or
Reset_Drv hardware
signal
Power Mgmt
Default = 0x00.
on Vcc POR or
Reset_Drv hardware
signal
Note 1: CR22 Bit 5 and Bit 7 are reset by VTR POR, only.
138
Table 54 - Chip Level Registers
REGISTER
OSC
ADDRESS
0x24 R/W
Default = 0x04, on
Vcc POR or
Reset_Drv hardware
signal.
DESCRIPTION
Bit[0] Reserved
Bit [1] PLL Control
=0
PLL is on (backward Compatible)
=1
PLL is off
Bits[3:2] OSC
= 01
Osc is on, BRG clock is on.
= 10
Same as above (01) case.
= 00
Osc is on, BRG Clock Enabled.
= 11
Osc is off, BRG clock is disabled.
STATE
C
Bit [5:4] Reserved, set to zero
Bit [6] 16-Bit Address Qualification
=0
12-Bit Address Qualification
=1
16-Bit Address Qualification
Bit[7] Reserved
Chip Level
Vendor Defined
0x25
Reserved - Writes are ignored, reads return 0.
Configuration
Address Byte 0
0x26
Bit[7:1] Configuration Address Bits [7:1]
Bit[0] = 0
See Note 1
C
0x27
Bit[7:0] Configuration Address Bits [15:8]
C
Default
=0xF0 (Sysopt=0)
=0x70 (Sysopt=1)
on Vcc POR or
Reset_Drv
Configuration
Address Byte 1
Default = 0x03
on Vcc POR or
Reset_Drv
Default = 0x00
on VCC POR and
Hard Reset
Chip Level
Vendor Defined
See Note 1
0x28
0x29 -0x2A
Bits[7:0] Reserved - Writes are ignored, reads
return 0.
Reserved - Writes are ignored, reads return 0.
139
Table 54 - Chip Level Registers
REGISTER
TEST 4
ADDRESS
DESCRIPTION
STATE
0x2B R/W
Test Modes: Reserved for SMSC. Users should not
write to this register, may produce undesired
results.
C
0x2C R/W
Test Modes: Reserved for SMSC. Users should not
write to this register, may produce undesired
results.
C
0x2D R/W
Test Modes: Reserved for SMSC. Users should not
write to this register, may produce undesired
results.
C
0x2E R/W
Test Modes: Reserved for SMSC. Users should not
write to this register, may produce undesired
results.
C
0x2F R/W
Test Modes: Reserved for SMSC. Users should not
write to this register, may produce undesired
results.
C
Default = 0x00, on
Vcc POR
TEST 5
Default = 0x00, on
Vcc POR
TEST 1
Default = 0x00, on
Vcc POR
TEST 2
Default = 0x00, on
Vcc POR
TEST 3
Default = 0x00, on
Vcc POR
Note 1: To allow the selection of the configuration address to a user defined location, these
Configuration Address Bytes are used. There is no restriction on the address chosen, except that A0
is 0, that is, the address must be on an even byte boundary. As soon as both bytes are changed, the
configuration space is moved to the specified location with no delay (Note: Write byte 0, then byte 1;
writing CR27 changes the base address).
The configuration address is only reset to its default address upon a Hard Reset or Vcc POR.
Note: The default configuration address is either 3F0 or 370, as specified by the SYSOPT pin.
140
Logical
Device
Configuration/Control
Registers [0x30-0xFF]
each logical device and is selected with the
Logical Device # Register (0x07).
Used to access the registers that are assigned
to each logical unit. This chip supports nine
logical units and has nine sets of logical device
registers. The six logical devices are Floppy,
Parallel, Serial 1, Serial 2, Keyboard Controller,
and Auxiliary_I/O. A separate set (bank) of
control and configuration registers exists for
The INDEX PORT is used to select a specific
logical device register. These registers are then
accessed through the DATA PORT.
The Logical Device registers are accessible only
when the device is in the Configuration State.
The logical register addresses are shown in the
table below.
Table 55 - Logical Device Registers
LOGICAL DEVICE
REGISTER
ADDRESS
DESCRIPTION
STATE
(0x30)
Bits[7:1] Reserved, set to zero.
Bit[0]
=1
Activates the logical device currently
selected through the Logical Device
# register.
=0
Logical device currently selected is
inactive
C
Logical Device Control
(0x31-0x37)
Reserved - Writes are ignored, reads return
0.
C
Logical Device Control
(0x38-0x3f)
Vendor Defined - Reserved - Writes are
ignored, reads return 0.
C
Memory Base Address
(0x40-0x5F)
Reserved - Writes are ignored, reads return
0.
C
I/O Base Address Note 2
(0x60-0x6F)
C
(see Device Base I/O
Address Table)
0x60,2,... =
addr[15:8]
Registers 0x60 and 0x61 set the base
address for the device. If more than one
base address is required, the second base
address is set by registers 0x62 and 0x63.
Default = 0x00
on Vcc POR or
Reset_Drv
0x61,3,... =
addr[7:0]
Note1, Note 3
Activate
Default = 0x00
on Vcc POR or
Reset_Drv
Refer to Table 64 for the number of base
address registers used by each device.
Unused registers will ignore writes and return
zero when read.
141
Table 55 - Logical Device Registers
LOGICAL DEVICE
REGISTER
ADDRESS
DESCRIPTION
STATE
(0x70,0x72)
0x70 is implemented for each logical device.
Refer to Interrupt Configuration Register
description. Only the keyboard controller
uses Interrupt Select register 0x72. Unused
register (0x72) will ignore writes and return
zero when read. Interrupts default to edge
high (ISA compatible).
C
(0x71,0x73)
Reserved - not implemented. These register
locations ignore writes and return zero when
read.
(0x74,0x75)
Only 0x74 is implemented for FDC, Serial
Port 2 and Parallel port.
0x75 is not
implemented and ignores writes and returns
zero when read. Refer to DMA Channel
Configuration.
32-Bit Memory Space
Configuration
(0x76-0xA8)
Reserved - not implemented. These register
locations ignore writes and return zero when
read.
Logical Device
(0xA9-0xDF)
Reserved - not implemented. These register
locations ignore writes and return zero when
read.
C
Logical Device
Configuration
(0xE0-0xFE)
Reserved - Vendor Defined (see SMSC
defined
Logical
Device
Configuration
Registers).
C
Reserved
C
Interrupt Select
Defaults :
0x70 = 0x00,
on Vcc POR or
Reset_Drv
0x72 = 0x00,
on Vcc POR or
Reset_Drv
DMA Channel Select
Default = 0x04
on Vcc POR or
Reset_Drv
Reserved
0xFF
C
Note 1: A logical device will be active and powered up according to the following equation:
DEVICE ON (ACTIVE) = (Activate Bit SET or Pwr/Control Bit SET).
The Logical device's Activate Bit and its Pwr/Control Bit are linked such that setting or
clearing one sets or clears the other.
Note 2: If the I/O Base Addr of the logical device is not within the Base I/O range as shown in the
Logical Device I/O map, then read or write is not valid and is ignored.
Note 3: The Activate Register for Logical Device 5 (Serial Port 2) is reset by VTR POR only.
142
Table 56 - I/O Base Address Configuration Register Description
LOGICAL
DEVICE
NUMBER
0x00
LOGICAL
DEVICE
FDC
REGISTER
INDEX
0x60,0x61
(Note 4)
BASE I/O
RANGE
(NOTE3)
[0x100:0x0FF8]
ON 8 BYTE BOUNDARIES
0x03
Parallel
Port
0x60,0x61
[0x100:0x0FFC]
ON 4 BYTE BOUNDARIES
(EPP Not supported)
or
[0x100:0x0FF8]
ON 8 BYTE BOUNDARIES
(all modes supported,
EPP is only available when
the base address is on an 8byte boundary)
0x04
Serial Port
1
0x60,0x61
[0x100:0x0FF8]
ON 8 BYTE BOUNDARIES
0x05
Serial Port
2
0x60,0x61
[0x100:0x0FF8]
ON 8 BYTE BOUNDARIES
0x62,0x63
[0x100:0x0FF8]
ON 8 BYTE BOUNDARIES
143
FIXED
BASE OFFSETS
+0 : SRA
+1 : SRB
+2 : DOR
+3 : TSR
+4 : MSR/DSR
+5 : FIFO
+7 : DIR/CCR
+0 : Data|ecpAfifo
+1 : Status
+2 : Control
+3 : EPP Address
+4 : EPP Data 0
+5 : EPP Data 1
+6 : EPP Data 2
+7 : EPP Data 3
+400h : cfifo|ecpDfifo|tfifo
|cnfgA
+401h : cnfgB
+402h : ecr
+0 : RB/TB|LSB div
+1 : IER|MSB div
+2 : IIR/FCR
+3 : LCR
+4 : MSR
+5 : LSR
+6 : MSR
+7 : SCR
+0 : RB/TB|LSB div
+1 : IER|MSB div
+2 : IIR/FCR
+3 : LCR
+4 : MSR
+5 : LSR
+6 : MSR
+7 : SCR
+0 : CIrCC SCE Registers
+1 : CIrCC SCE Registers
+2 : CIrCC SCE Registers
Table 56 - I/O Base Address Configuration Register Description
LOGICAL
DEVICE
NUMBER
LOGICAL
DEVICE
0x06
Reserved
0x07
KYBD
0x09
Reserved
REGISTER
INDEX
n/a
BASE I/O
RANGE
(NOTE3)
Not Relocatable
Fixed Base Address: 60,64
FIXED
BASE OFFSETS
+3 : CIrCC SCE Registers
+4 : CIrCC SCE Registers
+5 : CIrCC SCE Registers
+6 : CIrCC SCE Registers
+7 : CIrCC SCE Registers
+0 : Data Register
+4 : Command/Status Reg.
Note 3: This chip uses ISA address bits [A11:A0] to decode the base address of each of its logical
devices.
NAME
Interrupt
Request Level
Select 0
Default = 0x00
on Vcc POR or
Reset_Drv
Note:
Table 57 - Interrupt Select Configuration Register Description
REG INDEX
DEFINITION
0x70 (R/W)
Bits[3:0] selects which interrupt level is used for
Interrupt 0.
0x00= no interrupt selected
0x01= IRQ1
0x02= IRQ2/nSMI
0x03= IRQ3
0x04= IRQ4
0x05= IRQ5
0x06= IRQ6
0x07= IRQ7
0x08= IRQ8
0x09= IRQ9
0x0A= IRQ10
0x0B= IRQ11
0x0C= IRQ12
0x0D= IRQ13
0x0E= IRQ14
0x0F= IRQ15
Note: All interrupts are edge high (except ECP/EPP)
Note: nSMI is active low
STATE
C
An Interrupt is activated by setting the Interrupt Request Level Select 0 register to a non-zero
value AND :
For the FDC logical device by setting DMAEN, bit D3 of the Digital Output Register.
144
For the PP logical device by setting IRQE, bit D4 of the Control Port and in addition
For the PP logical device in ECP mode by clearing serviceIntr, bit D2 of the ecr.
For the Serial Port logical device by setting any combination of bits D0-D3 in the IER
And by setting the OUT2 bit in the UART's Modem Control (MCR) Register.
For the RTC by (refer to the RTC section of this spec).
For the KYBD by (refer to the KYBD controller section of this spec).
Note:
IRQ pins must tri-state if not used/selected by any Logical Device. Refer to Note A.
Note: nSMI must be disabled to use IRQ2.
Note:
All IRQ’s are available in Serial IRQ mode. Only IRQ[3:7] and IRQ[10:12] are available in
Parallel IRQ mode.
NAME
Table 58 - DMA Channel Select Configuration Register Description
REG INDEX
DEFINITION
DMA Channel
Select
Default = 0x04
on Vcc POR or
Reset_Drv
Note:
Note:
0x74 (R/W)
Bits[2:0] select the DMA Channel.
0x00= Reserved
0x01= DMA1
0x02= DMA2
0x03= DMA3
0x04-0x07= No DMA active
STATE
C
A DMA channel is activated by setting the DMA Channel Select register to [0x01-0x03] AND :
For the FDC logical device by setting DMAEN, bit D3 of the Digital Output Register.
For the PP logical device in ECP mode by setting dmaEn, bit D3 of the ecr.
For the UART 2 logical device, by setting the DMA Enable bit. Refer to the IrCC
specification.
DMAREQ pins must tri-state if not used/selected by any Logical Device. Refer to Note A.
145
Note A. Logical Device IRQ and DMA Operation
1.
IRQ and DMA Enable and Disable: Any time the IRQ or DACK for a logical block is
disabled by a register bit in that logical block, the IRQ and/or DACK must be disabled. This
is in addition to the IRQ and DACK disabled by the Configuration Registers (active bit or
address not valid).
a.
FDC: For the following cases, the IRQ and DACK used by the FDC are disabled (high
impedance). Will not respond to the DREQ
Digital Output Register (Base+2) bit D3 (DMAEN) set to "0".
The FDC is in power down (disabled).
b.
Serial Port 1 and 2:
Modem Control Register (MCR) Bit D2 (OUT2) - When OUT2 is a logic "0", the serial port
interrupt is forced to a high impedance state - disabled.
c.
Parallel Port:
I.
SPP and EPP modes: Control Port (Base+2) bit D4 (IRQE) set to "0", IRQ is
disabled (high impedance).
ii.
ECP Mode:
(1)
(DMA) dmaEn from ecr register. See table.
(2)
IRQ - See table.
MODE
(FROM ECR REGISTER)
000
PRINTER
d.
IRQ PIN
PDREQ PIN
CONTROLLED BY CONTROLLED BY
IRQE
dmaEn
001
SPP
IRQE
dmaEn
010
FIFO
(on)
dmaEn
011
ECP
(on)
dmaEn
100
EPP
IRQE
dmaEn
101
RES
IRQE
dmaEn
110
TEST
(on)
dmaEn
111
CONFIG
IRQE
dmaEn
Keyboard Controller: Refer to the KBD section of this spec.
146
Configuration Registers reset to their default
values only on hard resets generated by Vcc or
VTR POR (as shown) or the RESET_DRV
signal. These registers are not affected by soft
resets.
SMSC Defined Logical Device Configuration
Registers
The
SMSC
Specific
Logical
Device
Table 59 - Floppy Disk Controller, Logical Device 0 [Logical Device Number = 0x00]
NAME
REG INDEX
DEFINITION
STATE
FDD Mode Register
0xF0 R/W
Bit[0] Floppy Mode
=0
Normal Floppy Mode (default)
=1
Enhanced Floppy Mode 2 (OS2)
Bit[1] FDC DMA Mode
=0
Burst Mode is enabled
=1
Non-Burst Mode (default)
Bit[3:2] Interface Mode
= 11
AT Mode (default)
= 10
(Reserved)
= 01
PS/2
= 00
Model 30
Bit[4] Reserved
Bit[5] Reserved, set to zero
Bit[6] FDC Output Type Control
=0
FDC outputs are OD24 open drain (default)
=1
FDC outputs are O24 push-pull
Bit[7] FDC Output Control
=0
FDC outputs active (default)
=1
FDC outputs tri-stated
Note: Bits 6 & 7 do not affect the parallel port FDC
pins.
C
Default = 0x0E
on Vcc POR or
Reset_Drv
147
Table 59 - Floppy Disk Controller, Logical Device 0 [Logical Device Number = 0x00]
NAME
FDD Option
Register
REG INDEX
DEFINITION
STATE
0xF1 R/W
Bit[0] Forced Write Protect 0
= 0 Inactive (default)
= 1 FDD nWRTPRT input is forced active when
the drive has been selected.
Bit[1] Reserved
Bits[3:2] Density Select
= 00
Normal (default)
= 01
Normal (reserved for users)
= 10
1 (forced to logic "1")
= 11
0 (forced to logic "0")
Bit[7:4] Reserved.
nWRTPRT (to the FDC Core) = (nDS0 AND FORCE
WRTPRT) OR nWRTPRT (from the FDD Interface)
Note: Boot floppy is always drive 0.
Note: the Force Write Protect 0 bit also applies to the
Parallel Port FDC.
C
0xF2 R/W
Bits[1:0] Floppy Drive A Type
Bits[3:2] Floppy Drive B Type
Bits[5:4] Reserved (could be used to store Floppy
Drive C type)
Bits[7:6] Reserved (could be used to store Floppy
Drive D type)
Note: The FDC37B77x supports two floppy drives
Reserved, Read as 0 (read only)
C
0xF4 R/W
Bits[1:0] Drive Type Select: DT1, DT0
Bits[2] Read as 0 (read only)
Bits[4:3] Data Rate Table Select: DRT1, DRT0
Bits[5] Read as 0 (read only)
Bits[6] Precompensation Disable PTS
=0 Use Precompensation
=1 No Precompensation
Bits[7] Read as 0 (read only)
C
0xF5 R/W
Refer to definition and default for 0xF4
C
Default = 0x00
on Vcc POR or
Reset_Drv
FDD Type Register
Default = 0xFF
on Vcc POR or
Reset_Drv
0xF3 R
FDD0
Default = 0x00
on Vcc POR or
Reset_Drv
FDD1
148
C
Table 60 - Parallel Port, Logical Device 3 [Logical Device Number = 0x03]
NAME
PP Mode Register
REG INDEX
0xF0 R/W
Default = 0x3C
on Vcc POR or
Reset_Drv
DEFINITION
Bits[2:0] Parallel Port Mode
= 100 Printer Mode (default)
= 000 Standard and Bi-directional (SPP) Mode
= 001 EPP-1.9 and SPP Mode
= 101 EPP-1.7 and SPP Mode
= 010 ECP Mode
= 011 ECP and EPP-1.9 Mode
= 111 ECP and EPP-1.7 Mode
Bit[6:3] ECP FIFO Threshold
0111b (default)
Bit[7] PP Interupt Type
Not valid when the parallel port is in the Printer
Mode (100) or the Standard & Bi-directional Mode
(000).
=1
Pulsed Low, released to high-Z.
=0
IRQ follows nACK when parallel port in EPP
Mode or [Printer,SPP, EPP] under ECP.
IRQ level type when the parallel port is in ECP,
TEST, or Centronics FIFO Mode.
PP Mode Register 2
Default = 0x00
on Vcc POR or
Reset_Drv
0xF1 R/W
Bits[1:0] PPFDC - muxed PP/FDC control
= 00 Normal Parallel Port Mode
= 01 PPFD1:
Drive 0 is on the FDC pins
Drive 1 is on the Parallel port pins
= 10 PPFD2:
Drive 0 is on the Parallel port pins
Drive 1 is on the Parallel port pins
Bits[7:2] Reserved. Set to zero.
149
STATE
C
Table 61 - Serial Port 1, Logical Device 4 [Logical Device Number = 0x04]
NAME
Serial Port 1
Mode Register
REG INDEX
0xF0 R/W
Default = 0x00
on Vcc POR or
Reset_Drv
DEFINITION
Bit[0] MIDI Mode
=0
MIDI support disabled (default)
=1
MIDI support enabled
STATE
C
Bit[1] High Speed
=0
High Speed Disabled(default)
=1
High Speed Enabled
Bit[6:2] Reserved, set to zero
Bit[7]: Share IRQ
=0 UARTS use different IRQs
=1 UARTS share a common IRQ
See Note 1 below.
Note 1: To properly share and IRQ,
1. Configure UART1 (or UART2) to use the desired IRQ pin.
2. Configure UART2 (or UART1) to use No IRQ selected.
3. Set the share IRQ bit.
Note: If both UARTs are configured to use different IRQ pins and the share IRQ bit is set,
then both of the UART IRQ pins will assert when either UART generates an interrupt.
UART Interrupt Operation Table
Table 62 - Serial Port 2, Logical Device 5 [Logical Device Number = 0x05]
NAME
Serial Port 2
Mode Register
Default = 0x00
on Vcc POR or
Reset_Drv
REG INDEX
0xF0 R/W
DEFINITION
Bit[0] MIDI Mode
=0
MIDI support disabled (default)
=1
MIDI support enabled
Bit[1] High Speed
=0
High Speed disabled(default)
=1
High Speed enabled
Bit[7:2] Reserved, set to zero
150
STATE
C
Table 62 - Serial Port 2, Logical Device 5 [Logical Device Number = 0x05]
NAME
IR Option Register
REG INDEX
DEFINITION
STATE
0xF1 R/W
Bit[0] Receive Polarity
=0
Active High (Default)
=1
Active Low
Bit[1] Transmit Polarity
=0
Active High
=1
Active Low (Default)
Bit[2] Duplex Select
=0
Full Duplex (Default)
=1
Half Duplex
Bits[5:3] IR Mode
= 000 Standard (Default)
= 001 IrDA
= 010 ASK-IR
= 011 Reserved
= 1xx
Reserved
Bit[6] IR Location Mux
=0
Use Serial port TX2 and RX2 (Default)
=1
Use alternate IRRX (pin 61) and IRTX (pin
62)
Bit[7] Reserved, write 0.
C
0xF2
Bits [7:0]
These bits set the half duplex time-out for the IR port.
This value is 0 to 10msec in 100usec increments.
0= blank during transmit/receive
1= blank during transmit/receive + 100usec
...
Default = 0x02
on Vcc POR or
Reset_Drv
IR Half Duplex
Timeout
Default = 0x03
on Vcc POR or
Reset_Drv
Note:
Serial Port 2 (CIrCC) is reset by RESET_DRV.
151
Table 63 - KYBD, Logical Device 7 [Logical Device Number = 0x07]
NAME
KRST_GA20
REG INDEX
DEFINITION
0xF0
KRESET and GateA20 Select
R/W
Bit[7] Polarity Select for P12
= 0 P12 active low (default)
= 1 P12 active high
Bits[6:3] Reserved
Bit[2] Port 92 Select
= 0 Port 92 Disabled
= 1 Port 92 Enabled
Bit[1] Reserved
Bit[0] Reserved
Default = 0x00
on Vcc POR or
Reset_Drv
0xF1 -
STATE
Reserved - read as ‘0’
0xFF
Table 64 - Auxiliary I/O, Logical Device 8 [Logical Device Number = 0x08]
NAME
REG
DEFINITION
INDEX
SMI Enable
0xB4 R/W
This register is used to enable the different interrupt
Register 1
sources onto the group nSMI output.
1=Enable
Default = 0x00
0=Disable
on Vcc POR
Bit[0] Reserved
Bit[1] EN_PINT
Bit[2] EN_U2INT
Bit[3] EN_U1INT
Bit[4] EN_FINT
Bit[5] Reserved
Bit[6] Reserved
Bit[7] EN_WDT
SMI Enable
0xB5 R/W
This register is used to enable the different interrupt
Register 2
sources onto the group nSMI output, and the group
nSMI output onto the nSMI GPI/O pin.
Default = 0x00
on Vcc POR
Unless otherwise noted,
1=Enable
0=Disable
Bit[0] EN_MINT
Bit[1] EN_KINT
Bit[2] EN_IRINT
152
STATE
C
C
Table 64 - Auxiliary I/O, Logical Device 8 [Logical Device Number = 0x08]
NAME
REG
DEFINITION
INDEX
Bit[3] Reserved
Bit[4] EN_P12: Enable 8042 P1.2 to route internally
to nSMI. 0=Do not route to nSMI, 1=Enable
routing to nSMI.
Bit[5] Reserved
Bit[6] EN_SMI_S: Enables nSMI Interrupt onto
Serial IRQ.
Bit[7] Reserved
0xB6 R/W
This register is used to read the status of the SMI
SMI Status
inputs.
Register 1
The following bits must be cleared at their source.
Bit[0] Reserved
Default = 0x00
Bit[1] PINT (Parallel Port Interrupt)
on Vcc POR
Bit[2] U2INT (UART 2 Interrupt)
Bit[3] U1INT (UART 1 Interrupt)
Bit[4] FINT (Floppy Disk Controller Interrupt)
Bit[5] Reserved
Bit[6] Reserved
Bit[7] WDT (Watch Dog Timer)
SMI Status
0xB7 R/W
This register is used to read the status of the SMI
Register 2
inputs.
Bit[0] MINT: Mouse Interrupt. Cleared at source.
Default = 0x00
Bit[1] KINT: Keyboard Interrupt. Cleared at source.
on Vcc POR
Bit[2] IRINT: This bit is set by a transition on the IR
pin (RDX2 or IRRX as selected in CR L5-F1-B6
i.e., after the MUX). Cleared by a read of this
register.
Bit[3] Reserved
Bit[4] P12: 8042 P1.2. Cleared at source
Bit[7:5] Reserved
Default = 0x00
0xB8 R/W
Bits[7:0] Reserved
on VTR POR
Pin Multiplex
0xC0
Bit[0] Reserved
Controls
Bit[1] DMA 3 Select
Bit[2] Reserved
Default = 0x02 on
Bit[3] 8042 Select
Vcc POR
Bit[4] Reserved
Bit[5:7] Reserved
Force Disk Change
0xC1
Bit[0] Force Change 0
Default = 0x03 on
(R/W)
Bit[7:1] Reserved
Vcc POR
Force Change[0] can be written to 1 but is not
clearable by software.
153
STATE
C
C
C
C,R
Table 64 - Auxiliary I/O, Logical Device 8 [Logical Device Number = 0x08]
NAME
REG
DEFINITION
INDEX
Force Change 0 is cleared on nSTEP and nDS0
Floppy Data Rate
Select Shadow
0xC2
(R)
UART1 FIFO
Control Shadow
0xC3
UART2 FIFO
Control Shadow
0xC4
PME Control
Default = 0x00 on
VTR POR
0xC5
(R/W)
PME Status
Default = 0x00 on
POR VTR
0xC6
(R/w Clear)
DSKCHG (FDC DIR Register, Bit 7) = (nDS0 AND
Force Change 0) OR nDSKCHG
Bit[0] Data Rate Select 0
Bit[1] Data Rate Select 1
Bit[2] PRECOMP 0
Bit[3] PRECOMP 1
Bit[4] PRECOMP 2
Bit[5] Reserved
Bit[6] Power Down
Bit[7] Soft Reset
Bit[0] FIFO Enable
Bit[1] RCVR FIFO Reset
Bit[2] XMIT FIFO Reset
Bit[3] DMA Mode Select
Bit[5:4] Reserved
Bit[6] RCVR Trigger (LSB)
Bit[7] RCVR Trigger (MSB)
Bit[0] FIFO Enable
Bit[1] RCVR FIFO Reset
Bit[2] XMIT FIFO Reset
Bit[3] DMA Mode Select
Bit[5:4] Reserved
Bit[6] RCVR Trigger (LSB)
Bit[7] RCVR Trigger (MSB)
Bit[0] PME_En
= 0 nPME signal assertion is disabled (default)
= 1 Enables FDC37B77x to assert nPME signal
Bit[7:1] Reserved
PME_En is not affected by Vcc POR, SOFT RESET
or HARD RESET
Bit[0] PME_Status
= 0 (default)
= 1 Set when FDC37B77x would normally assert the
PCI nPME signal, independent of the state of the
PME_En bit.
Bit[7:1] Reserved
PME_Status is not affected by Vcc POR, SOFT
RESET or HARD RESET.
Writing a “1” to PME_Status will clear it and cause
the FDC37B77x to stop asserting nPME, in enabled.
154
STATE
C
C
C
Table 64 - Auxiliary I/O, Logical Device 8 [Logical Device Number = 0x08]
NAME
REG
DEFINITION
INDEX
Writing a “0” to PME_Status has no effect.
0xC7
This register indicates the state of the individual PME
PME Wake Status
(R/w Clear) wake sources, independent of the individual source
Default = 0x00 on
enables or the PME_En bit.
VTR POR
If the wake source has asserted a wake event, the
associated PME Wake Status bit will be a “1”.
Bit[0] CIR
Bit[1] RI2
Bit[2] RI1
Bit[3] KBD
Bit[4] MOUSE
Bit[7:5] Reserved
The PME Wake Status register is not affected by Vcc
POR, SOFT RESET or HARD RESET.
Writing a “1” to Bit[4:0] will clear it. Writing a “0” to
any bit in PME Wake Status Register has no effect.
PME Wake Enable
0xC8
This register is used to enable individual FDC37B77x
Default = 0x00 on
(R/W)
PME wake sources onto the nPME wake bus.
VTR POR
When the PME Wake Enable register bit for a wake
source is active (“1”), if the source asserts a wake
event and the PME_En bit is “1”, the source will
assert the PCI nPME signal.
When the PME Wake Enable register bit for a wake
source is inactive (“0”), the PME Wake Status
register will indicate the state of the wake source but
will not assert the PCI nPME signal.
Bit[0] CIR
Bit[1] RI2
Bit[2] RI1
Bit[3] KBD
Bit[4] MOUSE
Bit[7:5] Reserved
The PME Wake Enable register is not affected by Vcc
POR, SOFT RESET or HARD RESET.
Writing a “1” to Bit[4:0] will clear it. Writing a “0” to
any bit in PME Wake Enable register has no effect.
155
STATE
PIN
NAME
nRTS2
PIN
NAME
nCTS2
PIN
NAME
nDTR2
PIN
NAME
nDSR2
PIN
NAME
nDCD2
PIN
NAME
nRI2
Table 65 - nRTS MUXING
MUX CONTROL
16 BIT ADDRESS
QUAL. (CR24.6)
SELECTED FUNCTION
0
nRTS2 (default)
1
SA12
STATE OF
UNCONNECTED
INPUTS
0
Table 66 - nCTS2 MUXING
MUX CONTROL
16 BIT ADDRESS
QUAL. (CR24.6)
SELECTED FUNCTION
0
nCTS2 (default)
1
SA13
STATE OF
UNCONNECTED
INPUTS
1
0
Table 67 - nDTR2 MUXING
MUX CONTROL
16 BIT ADDRESS
QUAL. (CR24.6)
SELECTED FUNCTION
0
nDTR2 (default)
1
SA14
STATE OF
UNCONNECTED
INPUTS
0
Table 68 - nDSR2 MUXING
MUX CONTROL
16 BIT ADDRESS
QUAL. (CR24.6)
SELECTED FUNCTION
0
nDSR2 (default)
1
SA15
STATE OF
UNCONNECTED
INPUTS
1
0
Table 69 - nDCD2 MUXING
MUX CONTROL
8042COMSEL.
(LD8:CRC0.3)
SELECTED FUNCTION
0
nDCD2 (default)
1
P12
STATE OF
UNCONNECTED
INPUTS
1
-
Table 70 - nRI2 MUXING
MUX CONTROL
8042COMSEL.
(LD8:CRC0.3)
SELECTED FUNCTION
0
nR12 (default)
1
P16
STATE OF
UNCONNECTED
INPUTS
1
-
156
PIN NAME
DRQ3
PIN NAME
nDACK3
Table 71 - DRQ3 MUXING
MUX CONTROL
DMA3SEL
(LD8:CRC0.1)
SELECTED FUNCTION
1
DRQ3 (default)
0
P12
STATE OF
UNCONNECTED
INPUTS
-
Table 72 - nDACK3 MUXING
MUX CONTROL
DMA3SEL
(LD8:CRC0.1)
SELECTED FUNCTION
1
nDACK3 (default)
0
P16
STATE OF
UNCONNECTED
INPUTS
1
-
157
Table 73 - Auxiliary I/O, Logical Device 8 [Logical Device Number = 0x08]
NAME
WDT_TIME_OUT
REG INDEX
Bit[0] Reserved
Bit[1] Reserved
Bits[6:2] Reserved, = 00000
Bit[7] WDT Time-out Value Units Select
= 0 Minutes (default)
= 1 Seconds
C
0xF2
Watch-dog Timer Time-out Value
Binary coded, units = minutes (default) or seconds,
selectable via Bit[7] of Reg 0xF1, LD 8.
0x00 Time out disabled
0x01 Time-out = 1 minute (second)
.........
0xFF Time-out = 255 minutes (seconds)
C
0xF3
Watch-dog timer Configuration
Bit[0] Joy-stick Enable
=1
WDT is reset upon an I/O read or write of
the Game Port
=0
WDT is not affected by I/O reads or writes
to the Game Port.
Bit[1] Keyboard Enable
=1
WDT is reset upon a Keyboard interrupt.
=0
WDT is not affected by Keyboard interrupts.
Bit[2] Mouse Enable
=1
WDT is reset upon a Mouse interrupt.
=0
WDT is not affected by Mouse interrupts.
Bit[3] Reserved
Bits[7:4] WDT Interrupt Mapping
1111 = IRQ15
.........
0011 = IRQ3
0010 = Invalid
0001 = IRQ1
0000 = Disable
C
Default = 0x00
on Vcc POR or
Reset_Drv
WDT_CFG
Default = 0x00
on Vcc POR or
Reset_Drv
STATE
0xF1
Default = 0x00
on Vcc POR or
Reset_Drv
WDT_VAL
DEFINITION
158
Table 73 - Auxiliary I/O, Logical Device 8 [Logical Device Number = 0x08]
NAME
WDT_CTRL
Default = 0x00
Cleared by VTR
POR
REG INDEX
DEFINITION
STATE
0xF4
Watch-dog timer Control
Bit[0] Watch-dog Status Bit, R/W
=1
WD timeout occurred
=0
WD timer counting
Bit[1] Reserved
Bit[2] Force Timeout, W
=1
Forces WD timeout event; this bit is selfclearing
Bit[3] P20 Force Timeout Enable, R/W
=1
Allows rising edge of P20, from the
Keyboard Controller, to force the WD
timeout event. A WD timeout event may
still be forced by setting the Force Timeout
Bit, bit 2.
=0
P20 activity does not generate the WD
timeout event.
Note: The P20 signal will remain high for a minimum
of 1us and can remain high indefinitely. Therefore,
when P20 forced timeouts are enabled, a selfclearing edge-detect circuit is used to generate a
signal which is ORed with the signal generated by
the Force Timeout Bit.
Bit[7:4] Reserved. Set to 0
C
159
OPERATIONAL DESCRIPTION
MAXIMUM GUARANTEED RATINGS*
Operating Temperature Range......................................................................................... 0oC to +70oC
Storage Temperature Range..........................................................................................-55o to +150oC
Lead Temperature Range (soldering, 10 seconds) .................................................................... +325oC
Positive Voltage on any pin, with respect to Ground ................................................................Vcc+0.3V
Negative Voltage on any pin, with respect to Ground.................................................................... -0.3V
Maximum Vcc ................................................................................................................................. +7V
*Stresses above those listed above could cause permanent damage to the device. This is a stress
rating only and functional operation of the device at any other condition above those indicated in the
operation sections of this specification is not implied.
Note: When powering this device from laboratory or system power supplies, it is important that the
Absolute Maximum Ratings not be exceeded or device failure can result. Some power supplies exhibit
voltage spikes on their outputs when the AC power is switched on or off. In addition, voltage
transients on the AC power line may appear on the DC output. If this possibility exists, it is suggested
that a clamp circuit be used.
DC ELECTRICAL CHARACTERISTICS
(TA = 0°C - 70°C, Vcc = +5 V ± 10%)
PARAMETER
SYMBOL
MIN
TYP
MAX
UNITS
0.8
V
COMMENTS
I Type Input Buffer
Low Input Level
VILI
High Input Level
VIHI
2.0
TTL Levels
V
IS Type Input Buffer
Low Input Level
VILIS
High Input Level
VIHIS
Schmitt Trigger Hysteresis
VHYS
0.8
2.2
250
V
Schmitt Trigger
V
Schmitt Trigger
mV
ICLK Input Buffer
Low Input Level
VILCK
High Input Level
VIHCK
0.4
2.2
160
V
V
PARAMETER
SYMBOL
MIN
TYP
MAX
UNITS
COMMENTS
ICLK2 Input Buffer
500
Input Level
mV
VP-P
Input Leakage
(All I and IS buffers)
Low Input Leakage
IIL
-10
+10
µA
VIN = 0
High Input Leakage
IIH
-10
+10
µA
VIN = VCC
0.4
V
IOL = 4 mA
V
IOH = -2 mA
+10
µA
VIN = 0 to VCC
(Note 1)
0.4
V
IOL = 8 mA
V
IOH = -8 mA
µA
VIN = 0 to VCC
(Note 1)
O4 Type Buffer
Low Output Level
VOL
High Output Level
VOH
2.4
Output Leakage
IOL
-10
O8SR Type Buffer
Low Output Level
VOL
High Output Level
VOH
2.4
Output Leakage
IOL
-10
Rise Time
TRT
5
ns
Fall Time
TFL
5
ns
+10
O24 Type Buffer
Low Output Level
VOL
0.4
High Output Level
VOH
2.4
Output Leakage
IOL
-10
161
+10
V
IOL = 24 mA
V
IOH = -12 mA
µA
VIN = 0 to VCC
(Note 1)
PARAMETER
SYMBOL
MIN
TYP
MAX
UNITS
COMMENTS
0.4
V
IOL = 12 mA
V
IOH = -6 mA
+10
µA
VIN = 0 to VCC
(Note 1)
0.4
V
IOL = 12 mA
V
IOH = -6 mA
+10
µA
VIN = 0 to VCC
(Note 1)
0.4
V
IOL = 24 mA
V
IOH = -12 mA
+10
µA
VIN = 0 to VCC
(Note 1)
0.4
V
IOL = 16 mA
V
IOH = -16 mA
µA
VIN = 0 to VCC
(Note 1)
IO12 Type Buffer
Low Output Level
VOL
High Output Level
VOH
2.4
Output Leakage
IOL
-10
O12 Type Buffer
Low Output Level
VOL
High Output Level
VOH
2.4
Output Leakage
IOL
-10
O24PD Type Buffer
Low Output Level
VOL
High Output Level
VOH
2.4
Output Leakage
IOL
-10
O16SR Type Buffer
Low Output Level
VOL
High Output Level
VOH
2.4
Output Leakage
IOL
-10
Rise Time
TRT
5
ns
Fall Time
TFL
5
ns
+10
OD16 Type Buffer
Low Output Level
VOL
Output Leakage
IOL
-10
162
0.4
V
IOL = 16 mA
+10
µA
VIN = 0 to VCC
(Note 1)
PARAMETER
SYMBOL
MIN
TYP
MAX
UNITS
COMMENTS
OD24 Type Buffer
Low Output Level
VOL
0.4
V
IOL = 24 mA
Output Leakage
IOL
+10
µA
VIN = 0 to VCC
(Note 1)
Low Output Level
VOL
0.4
V
IOL = 48 mA
Output Leakage
IOL
+10
µA
VIN = 0 to VCC
(Note 1)
Low Output Level
VOL
0.4
V
IOL = 2 mA
High Output Level
VOH
3.5
V
IOH = -2 mA
Output Leakage
IOL
-10
+10
µA
VIN = 0 to VCC
(Note 1)
ChiProtect
(SLCT, PE, BUSY, nACK,
nERROR)
IIL
± 10
µA
VCC = 0V
VIN = 6V Max
Low Output Level
VOL
0.4
V
IOL = 12 mA
Output Leakage
IOL
+10
µA
VIN = 0 to VCC
(Note 1)
Backdrive
(nSTROBE, nAUTOFD, nINIT,
nSLCTIN)
IIL
± 10
µA
VCC = 0V
VIN = 6V Max
Backdrive
(PD0-PD7)
IIL
± 10
µA
VCC = 0V
VIN = 6V Max
VCC Suppy Current Active
ICCI
4.5
90
mA
Trickle Supply Voltage
VTR
VCC
min
VCC
max
V
OD48 Type Buffer
OCLK2 Type Buffer
OD12 Type Buffer
-10
-.5V
163
70
ALL OUTPUTS
OPEN.
VCC must not be
greater than .5V
above VTR
PARAMETER
VTR Supply Current Active
SYMBOL
MIN
TYP
IVRI
MAX
UNITS
25
mA
COMMENTS
All outputs driven
Note 1: All output leakage’s are measured with the current pins in high impedance
Note 2: Output leakage is measured with the low driving output off, either for a high level output or a
high impedance state.
CAPACITANCE TA = 25°C; fc = 1MHz; VCC = 5V
PARAMETER
Clock Input Capacitance
Input Capacitance
Output Capacitance
SYMBOL
CIN
MIN
LIMITS
TYP
MAX
20
UNIT
pF
CIN
10
pF
COUT
20
pF
164
TEST CONDITION
All pins except pin
under test tied to AC
ground
TIMING DIAGRAMS
For the Timing Diagrams shown, the following capacitive loads are used.
CAPACITANCE
TOTAL (pF)
240
240
120
120
240
240
240
240
240
240
240
240
100
100
100
100
100
100
240
240
240
240
240
240
240
240
240
NAME
SD[0:7]
IOCHRDY
IRQ[3:7,10:12]
DRQ[1:3]
nWGATE
nWDATA
nHDSEL
nDIR
nSTEP
nDS0
nMTR0
DRVDEN[1:0]
TXD1
nRTS1
nDTR1
TXD2
nRTS2
nDTR2
PD[0:7]
nSLCTIN
nINIT
nALF
nSTB
KDAT
KCLK
MDAT
MCLK
165
t3
SAx
t4
SD<7:0>
nIOW
t1
t2
t5
FIGURE 2 - IOW TIMING FOR PORT 92
IOW Timing
NAME
DESCRIPTION
MIN
TYP
MAX
UNITS
t1
SAx Valid to nIOW Asserted
40
ns
t2
SDATA Valid to nIOW Asserted
0
ns
t3
nIOW Asserted to SAx Invalid
10
ns
t4
nIOW Deasserted to DATA Invalid
t5
nIOW Deasserted to nIOW or nIOR Asserted
166
0
ns
100
ns
t 1
t 2
V c c
t 3
A ll H o s t
A c c e s s e s
FIGURE 3 - POWER-UP TIMING
NAME
DESCRIPTION
MIN
TYP
MAX
UNITS
t1
Vcc Slew from 4.5V to 0V
300
µs
t2
Vcc Slew from 0V to 4.5V
100
µs
t3
All Host Accesses After Powerup (Note 1)
125
Note 1: Internal write-protection period after Vcc passes 4.5 volts on power-up
167
500
µs
t10
AEN
t3
SA[x], nCS
t2
t1
t4
t6
nIOW
t5
SD[x]
DATA VALID
t7
FINTR
t8
PINTR
t9
IBF
FIGURE 4 - ISA WRITE
NAME
DESCRIPTION
MIN
TYP
MAX
UNITS
t1
SA[x], nCS and AEN valid to nIOW asserted
10
ns
t2
nIOW asserted to nIOW deasserted
80
ns
t3
nIOW asserted to SA[x], nCS invalid
10
ns
t4
SD[x] Valid to nIOW deasserted
45
ns
t5
SD[x] Hold from nIOW deasserted
t6
nIOW deasserted to nIOW asserted
t7
nIOW deasserted to FINTR deasserted (Note 1)
55
ns
t8
nIOW deasserted to PINTER deasserted (Note 2)
260
ns
t9
IBF (internal signal) asserted from nIOW deasserted
t10
nIOW deasserted to AEN invalid
0
25
Note 1: FINTR refers to the IRQ used by the floppy disk
Note 2: PINTR refers to the IRQ used by the parallel port
168
ns
40
10
ns
ns
ns
t13
AEN
t3
SA[x], nCS
t1
t7
t2
t6
nIOR
t4
t5
SD[x]
DATA VALID
PD[x], nERROR,
PE, SLCT, ACK, BUSY
t10
FINTER
t9
PINTER
t11
PCOBF
t12
AUXOBF1
t8
nIOR/nIOW
FIGURE 5 - ISA READ
SEE TIMING PARAMETERS ON NEXT PAGE
169
ISA READ TIMING
DESCRIPTION
NAME
MIN
TYP
MAX
UNITS
t1
SA[x], nCS and AEN valid to nIOR asserted
10
ns
t2
nIOR asserted to nIOR deasserted
50
ns
t3
nIOR asserted to SA[x], nCS invalid
10
ns
t4
nIOR asserted to Data Valid
t5
Data Hold/float from nIOR deasserted
10
t6
nIOR deasserted
25
ns
t8
nIOR asserted after nIOW deasserted
80
ns
t8
nIOR/nIOR, nIOW/nIOW transfers from/to ECP FIFO
150
ns
t7
Parallel Port setup to nIOR asserted
20
ns
t9
nIOR asserted to PINTER deasserted
55
ns
t10
nIOR deasserted to FINTER deasserted
260
ns
t11
nIOR deasserted to PCOBF deasserted (Notes 3,5)
80
ns
t12
nIOR deasserted to AUXOBF1 deasserted (Notes 4,5)
80
ns
t13
nIOW deasserted to AEN invalid
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
10
FINTR refers to the IRQ used by the floppy disk.
PINTR refers to the IRQ used by the parallel port.
PCOBF is used for the Keyboard IRQ.
AUXOBF1 is used for the Mouse IRQ.
Applies only if deassertion is performed in hardware.
170
50
ns
25
ns
ns
t2
PCOBF
t1
AUXOBF1
nWRT
t3
IBF
nRD
FIGURE 6 - INTERNAL 8042 CPU TIMING
NAME
DESCRIPTION
MIN
TYP
MAX
UNITS
t1
nWRT deasserted to AUXOBF1 asserted (Notes 1,2)
40
ns
t2
nWRT deasserted to PCOBF asserted (Notes 1,3)
40
ns
t3
nRD deasserted to IBF deasserted (Note 1)
40
ns
Note 1: IBF, nWRT and nRD are internal signals.
Note 2: PCOBF is used for the Keyboard IRQ.
Note 3: AUXOBF1 is used for the Mouse IRQ.
171
t1
t2
t2
CLOCKI
FIGURE 7A - INPUT CLOCK TIMING
NAME
DESCRIPTION
MIN
TYP
MAX
UNITS
t1
Clock Cycle Time for 14.318MHZ
70
ns
t2
Clock High Time/Low Time for 14.318MHz
35
ns
t1
Clock Cycle Time for 32KHZ
31.25
µs
Clock High Time/Low Time for 32KHz
16.53
t2
Clock Rise Time/Fall Time (not shown)
µs
5
ns
FIGURE 7B - RESET TIMING
t4
RESET_DRV
NAME
t4
DESCRIPTION
MIN
RESET width (Note 1)
1.5
TYP
MAX
UNITS
µs
Note 1: The RESET width is dependent upon the processor clock. The RESET must be active while
the clock is running and stable.
172
t15
AEN
t16
t3
t2
FDRQ,
PDRQ
t1
t4
nDACK
t12
t14
t11
t6
t5
t8
nIOR
or
nIOW
t10
t9
t7
DATA
(DO-D7)
DATA VALID
t13
TC
FIGURE 8A - DMA TIMING (SINGLE TRANSFER MODE)
NAME
DESCRIPTION
MIN
TYP
MAX
0
UNITS
t1
nDACK Delay Time from FDRQ High
t2
DRQ Reset Delay from nIOR or nIOW
100
ns
ns
t3
FDRQ Reset Delay from nDACK Low
100
ns
t4
nDACK Width
t5
150
ns
nIOR Delay from FDRQ High
0
ns
t6
nIOW Delay from FDRQ High
0
t7
Data Access Time from nIOR Low
t8
Data Set Up Time to nIOW High
40
t9
Data to Float Delay from nIOR High
10
t10
Data Hold Time from nIOW High
10
ns
t11
nDACK Set Up to nIOW/nIOR Low
5
ns
t12
nDACK Hold after nIOW/nIOR High
10
ns
t13
TC Pulse Width
60
ns
t14
AEN Set Up to nIOR/nIOW
40
ns
t15
AEN Hold from nDACK
10
ns
t16
TC Active to PDRQ Inactive
ns
100
ns
60
100
173
ns
ns
ns
t15
AEN
t16
t3
t2
FDRQ,
PDRQ
t1
t4
nDACK
t12
t14
t11
t6
t8
t5
nIOR
or
nIOW
t10
t9
t7
DATA
(DO-D7)
DATA VALID
DATA VALID
t13
TC
FIGURE 8B - DMA TIMING (BURST TRANSFER MODE)
NAME
DESCRIPTION
MIN
TYP
MAX
0
UNITS
t1
nDACK Delay Time from FDRQ High
t2
DRQ Reset Delay from nIOR or nIOW
100
ns
ns
t3
FDRQ Reset Delay from nDACK Low
100
ns
t4
nDACK Width
t5
150
ns
nIOR Delay from FDRQ High
0
ns
t6
nIOW Delay from FDRQ High
0
t7
Data Access Time from nIOR Low
t8
Data Set Up Time to nIOW High
40
t9
Data to Float Delay from nIOR High
10
t10
Data Hold Time from nIOW High
10
ns
t11
nDACK Set Up to nIOW/nIOR Low
5
ns
t12
nDACK Hold after nIOW/nIOR High
10
ns
t13
TC Pulse Width
60
ns
t14
AEN Set Up to nIOR/nIOW
40
ns
t15
AEN Hold from nDACK
10
t16
TC Active to PDRQ Inactive
ns
100
ns
60
ns
ns
100
174
ns
ns
t3
nDIR
t4
t1
t2
nSTEP
t5
nDS0-3
t6
nINDEX
t7
nRDATA
t8
nWDATA
nIOW
t9
t9
nDS0-1,
MTR0-1
FIGURE 9 - DISK DRIVE TIMING (AT MODE ONLY)
NAME
DESCRIPTION
MIN
TYP
MAX
UNITS
t1
nDIR Set Up to STEP Low
4
X*
t2
nSTEP Active Time Low
24
X*
t3
nDIR Hold Time after nSTEP
96
X*
t4
nSTEP Cycle Time
132
X*
t5
nDS0-1 Hold Time from nSTEP Low
20
X*
t6
nINDEX Pulse Width
2
X*
t7
nRDATA Active Time Low
40
ns
t8
nWDATA Write Data Width Low
.5
Y*
t9
nDS0-1, MTRO-1 from End of nIOW
25
ns
*X specifies one MCLK period and Y specifies one WCLK period.
MCLK = 16 x Data Rate (at 500 kb/s MCLK = 8 MHz)
WCLK = 2 x Data Rate (at 500 kb/s WCLK = 1 MHz)
175
nIOW
t1
nRTSx,
nDTRx
t5
IRQx
nCTSx,
nDSRx,
nDCDx
t6
t2
t4
IRQx
nIOW
t3
IRQx
nIOR
nRIx
FIGURE 10 - SERIAL PORT TIMING
NAME
DESCRIPTION
MIN
TYP
MAX
UNITS
t1
nRTSx, nDTRx Delay from nIOW
200
ns
t2
IRQx Active Delay from nCTSx, nDSRx, nDCDx
100
ns
t3
IRQx Inactive Delay from nIOR (Leading Edge)
120
ns
t4
IRQx Inactive Delay from nIOW (Trailing Edge)
125
ns
t5
IRQx Inactive Delay from nIOW
100
ns
t6
IRQx Active Delay from nRIx
100
ns
10
176
PD0- PD7
t6
nIOW
t1
nINIT, nSTROBE.
nAUTOFD, SLCTIN
nACK
t2
nPINTR
(SPP)
t4
PINTR
(ECP or EPP Enabled)
t3
nFAULT (ECP)
nERROR
(ECP)
t5
t2
t3
PINTR
FIGURE 11 - PARALLEL PORT TIMING
NAME
DESCRIPTION
MIN
t1
PD0-7, nINIT, nSTROBE, nAUTOFD Delay from
nIOW
t2
PINTR Delay from nACK, nFAULT
t3
PINTR Active Low in ECP and EPP Modes
t4
TYP
MAX
UNITS
100
ns
60
ns
300
ns
PINTR Delay from nACK
105
ns
t5
nERROR Active to PINTR Active
105
ns
t6
PD0 - PD7 Delay from IOW Active
100
ns
Note:
PINTR refers to the IRQ used by the parallel port.
177
200
t18
A0-A10
t9
SD<7:0>
t17
t8
nIOW
t12
t10
IOCHRDY
nWRITE
t19
t11
t13
t22
t20
t2
t1
t5
PD<7:0>
t14
nDATAST
t16
t3
t4
nADDRSTB
t6
t15
t7
nWAIT
t21
PDIR
FIGURE 12A - EPP 1.9 DATA OR ADDRESS WRITE CYCLE
SEE TIMING PARAMETERS ON NEXT PAGE
178
FIGURE 12B - EPP 1.9 DATA OR ADDRESS WRITE CYCLE TIMING
NAME
DESCRIPTION
MIN
TYP
MAX
UNITS
t1
nIOW Asserted to PDATA Valid
0
50
ns
t2
nWAIT Asserted to nWRITE Change (Note 1)
60
185
ns
t3
nWRITE to Command Asserted
5
35
ns
t4
nWAIT Deasserted to Command Deasserted
(Note 1)
60
190
ns
t5
nWAIT Asserted to PDATA Invalid (Note 1)
0
t6
Time Out
10
t7
Command Deasserted to nWAIT Asserted
0
ns
t8
SDATA Valid to nIOW Asserted
10
ns
ns
12
µs
t9
nIOW Deasserted to DATA Invalid
0
t10
nIOW Asserted to IOCHRDY Asserted
0
24
ns
ns
t11
nWAIT Deasserted to IOCHRDY Deasserted
(Note 1)
60
160
ns
t12
IOCHRDY Deasserted to nIOW Deasserted
10
t13
nIOW Asserted to nWRITE Asserted
0
70
ns
t14
nWAIT Asserted to Command Asserted (Note 1)
60
210
ns
t15
Command Asserted to nWAIT Deasserted
0
10
µs
t16
PDATA Valid to Command Asserted
10
ns
t17
Ax Valid to nIOW Asserted
40
ns
t18
nIOW Asserted to Ax Invalid
10
ns
t19
nIOW Deasserted to nIOW or nIOR Asserted
40
t20
nWAIT Asserted to nWRITE Asserted (Note 1)
60
t21
nWAIT Asserted to PDIR Low
0
ns
t22
PDIR Low to nWRITE Asserted
0
ns
ns
ns
185
Note 1: nWAIT must be filtered to compensate for ringing on the parallel bus cable.
considered to have settled after it does not transition for a minimum of 50 nsec.
179
ns
WAIT is
t20
A0-A10
IOR
t19
t11
t13
t22
t12
SD<7:0>
IOCHRDY
t18
t10
t8
t24
t23
t27
PDIR
t9
t21
t17
nWRITE
t2
t25
PData bus driven
by peripheral
t5
t4
t16
PD<7:0>
t28
t26
t1
DATASTB
t14
t3
ADDRSTB
t15
t7
nWAIT
FIGURE 13A - EPP 1.9 DATA OR ADDRESS READ CYCLE
SEE TIMING PARAMETERS ON NEXT PAGE
180
t6
FIGURE 13B - EPP 1.9 DATA OR ADDRESS READ CYCLE TIMING PARAMETERS
NAME
DESCRIPTION
MIN
TYP
MAX
UNITS
t1
PDATA Hi-Z to Command Asserted
0
30
ns
t2
nIOR Asserted to PDATA Hi-Z
0
50
ns
t3
nWAIT Deasserted to Command Deasserted
(Note 1)
60
180
ns
t4
Command Deasserted to PDATA Hi-Z
0
t5
Command Asserted to PDATA Valid
0
ns
t6
PDATA Hi-Z to nWAIT Deasserted
0
µs
t7
PDATA Valid to nWAIT Deasserted
0
t8
nIOR Asserted to IOCHRDY Asserted
0
t9
nWRITE Deasserted to nIOR Asserted (Note 2)
0
t10
nWAIT Deasserted to IOCHRDY Deasserted
(Note 1)
60
t11
IOCHRDY Deasserted to nIOR Deasserted
0
t12
nIOR Deasserted to SDATA Hi-Z (Hold Time)
0
t13
PDATA Valid to SDATA Valid
t14
nWAIT Asserted to Command Asserted
t15
ns
ns
24
ns
160
ns
ns
ns
40
ns
0
75
ns
0
195
ns
Time Out
10
12
µs
t16
nWAIT Deasserted to PDATA Driven (Note 1)
60
190
ns
t17
nWAIT Deasserted to nWRITE Modified (Notes 1,2)
60
190
ns
t18
SDATA Valid to IOCHRDY Deasserted (Note 3)
0
85
t19
Ax Valid to nIOR Asserted
40
t20
nIOR Deasserted to Ax Invalid
10
10
t21
nWAIT Asserted to nWRITE Deasserted
0
185
t22
nIOR Deasserted to nIOW or nIOR Asserted
40
t23
nWAIT Asserted to PDIR Set (Note 1)
60
t24
PDATA Hi-Z to PDIR Set
0
t25
nWAIT Asserted to PDATA Hi-Z (Note 1)
60
180
ns
t26
PDIR Set to Command
0
20
ns
t27
nWAIT Deasserted to PDIR Low (Note 1)
60
180
ns
t28
nWRITE Deasserted to Command
1
Note 1:
Note 2:
Note 3:
nWAIT is considered to have settled after it does not transition for a minimum of 50 ns.
When not executing a write cycle, EPP nWRITE is inactive high.
85 is true only if t7 = 0.
181
ns
ns
ns
ns
ns
185
ns
ns
ns
t18
A0-A10
t9
SD<7:0>
nIOW
t17
t8
t6
t19
t12
t10
t20
IOCHRDY
t11
t13
t2
t1
t5
nWRITE
PD<7:0>
t16
t3
t4
nDATAST
nADDRSTB
t21
nWAIT
PDIR
FIGURE 14A - EPP 1.7 DATA OR ADDRESS WRITE CYCLE
SEE TIMING PARAMETERS ON NEXT PAGE
182
FIGURE 14B - EPP 1.7 DATA OR ADDRESS WRITE CYCLE PARAMETERS
NAME
DESCRIPTION
MIN
TYP
MAX
UNITS
t1
nIOW Asserted to PDATA Valid
0
50
ns
t2
Command Deasserted to nWRITE Change
0
40
ns
t3
nWRITE to Command
5
35
ns
t4
nIOW Deasserted to Command Deasserted (Note 2)
50
ns
t5
Command Deasserted to PDATA Invalid
50
t6
Time Out
10
t8
SDATA Valid to nIOW Asserted
10
ns
t9
nIOW Deasserted to DATA Invalid
0
ns
t10
nIOW Asserted to IOCHRDY Asserted
0
t11
nWAIT Deasserted to IOCHRDY Deasserted
t12
IOCHRDY Deasserted to nIOW Deasserted
10
t13
nIOW Asserted to nWRITE Asserted
0
50
ns
t16
PDATA Valid to Command Asserted
10
35
ns
t17
Ax Valid to nIOW Asserted
40
t18
nIOW Deasserted to Ax Invalid
10
µs
t19
nIOW Deasserted to nIOW or nIOR Asserted
100
ns
t20
nWAIT Asserted to IOCHRDY Deasserted
t21
Command Deasserted to nWAIT Deasserted
ns
12
24
40
ns
ns
ns
ns
45
0
µs
ns
ns
Note 1: nWRITE is controlled by clearing the PDIR bit to "0" in the control register before performing
an EPP Write.
Note 2: The number is only valid if nWAIT is active when IOW goes active.
183
t20
A0-A10
t15
t11
t19
t22
nIOR
t13
t12
SD<7:0>
t8
t10
t3
IOCHRDY
nWRITE
t5
t4
PD<7:0>
t23
t2
nDATASTB
nADDRSTB
t21
nWAIT
PDIR
FIGURE 15A - EPP 1.7 DATA OR ADDRESS READ CYCLE
SEE TIMING PARAMETERS ON NEXT PAGE
184
FIGURE 15B - EPP 1.7 DATA OR ADDRESS READ CYCLE PARAMETERS
NAME
DESCRIPTION
MIN
TYP
MAX
UNITS
50
ns
40
ns
t2
nIOR Deasserted to Command Deasserted
t3
nWAIT Asserted to IOCHRDY Deasserted
0
t4
Command Deasserted to PDATA Hi-Z
0
ns
t5
Command Asserted to PDATA Valid
0
ns
t8
nIOR Asserted to IOCHRDY Asserted
t10
nWAIT Deasserted to IOCHRDY Deasserted
t11
IOCHRDY Deasserted to nIOR Deasserted
0
t12
nIOR Deasserted to SDATA High-Z (Hold Time)
0
t13
PDATA Valid to SDATA Valid
t15
Time Out
10
t19
Ax Valid to nIOR Asserted
40
ns
t20
nIOR Deasserted to Ax Invalid
10
ns
t21
Command Deasserted to nWAIT Deasserted
0
ns
t22
nIOR Deasserted to nIOW or nIOR Asserted
40
t23
nIOR Asserted to Command Asserted
Note:
24
50
ns
ns
ns
40
ns
40
ns
12
µs
ns
55
ns
WRITE is controlled by setting the PDIR bit to "1" in the control register before performing an
EPP Read.
185
ECP PARALLEL PORT TIMING
Parallel Port FIFO (Mode 101)
specified setup time prior to the falling edge of
HostClk. The peripheral then sets PeriphAck
(Busy) high to acknowledge the handshake. The
host then sets HostClk (nStrobe) high. The
peripheral then accepts the data and sets
PeriphAck (Busy) low, completing the transfer.
This sequence is shown in Figure 17.
The standard parallel port is run at or near the
peak 500KBytes/sec allowed in the forward
direction using DMA. The state machine does
not examine nACK and begins the next transfer
based on Busy. Refer to Figure 17.
ECP Parallel Port Timing
The timing is designed to provide 3 cable
round-trip times for data setup if Data is driven
simultaneously with HostClk (nStrobe).
The timing is designed to allow operation at
approximately 2.0 Mbytes/sec over a 15ft cable.
If a shorter cable is used then the bandwidth will
increase.
Reverse-Idle Phase
The peripheral has no data to send and keeps
PeriphClk high. The host is idle and keeps
HostAck low.
Forward-Idle
When the host has no data to send it keeps
HostClk (nStrobe) high and the peripheral will
leave PeriphClk (Busy) low.
Reverse Data Transfer Phase
The interface transfers data and commands
from the peripheral to the host using an interlocked HostAck and PeriphClk.
Forward Data Transfer Phase
The interface transfers data and commands
from the host to the peripheral using an interlocked PeriphAck and HostClk. The peripheral
may indicate its desire to send data to the host
by asserting nPeriphRequest.
The Reverse Data Transfer Phase may be entered from the Reverse-Idle Phase. After the
previous byte has beed accepted the host sets
HostAck (nALF) low. The peripheral then sets
PeriphClk (nACK) low when it has data to send.
The data must be stable for the specified setup
time prior to the falling edge of PeriphClk. When
the host is ready to accept a byte it sets
HostAck (nALF) high to acknowledge the
handshake. The peripheral then sets PeriphClk
(nACK) high. After the host has accepted the
data it sets HostAck (nALF) low, completing the
transfer. This sequence is shown in Figure 18.
The Forward Data Transfer Phase may be
entered from the Forward-Idle Phase. While in
the Forward Phase the peripheral may
asynchronously assert the nPeriphRequest
(nFault) to request that the channel be reversed.
When the peripheral is not busy it sets
PeriphAck (Busy) low. The host then sets
HostClk (nStrobe) low when it is prepared to
send data. The data must be stable for the
186
specified as open-collector), the drivers are
dynamically changed from open-collector to
totem-pole. The timing for the dynamic driver
change is specified in
then
IEEE 1284
Extended Capabilities Port Protocol and ISA
Interface Standard, Rev. 1.14, July 14, 1993,
available from Microsoft. The dynamic driver
change must be implemented properly to
prevent glitching the outputs.
Output Drivers
To facilitate higher performance data transfer,
the use of balanced CMOS active drivers for
critical signals (Data, HostAck, HostClk,
PeriphAck, PeriphClk) are used ECP Mode.
Because the use of active drivers can present
compatibility
problems
in Compatible
Mode (the control signals, by tradition, are
t6
t3
PDATA
t1
nSTROBE
t2
t5
t4
BUSY
FIGURE 16 - PARALLEL PORT FIFO TIMING
NAME
DESCRIPTION
MIN
TYP
MAX
UNITS
t1
DATA Valid to nSTROBE Active
600
ns
t2
nSTROBE Active Pulse Width
600
ns
t3
DATA Hold from nSTROBE Inactive (Note 1)
450
ns
t4
nSTROBE Active to BUSY Active
t5
BUSY Inactive to nSTROBE Active
680
ns
t6
BUSY Inactive to PDATA Invalid (Note 1)
80
ns
500
ns
Note 1: The data is held until BUSY goes inactive or for time t3, whichever is longer. This only
applies if another data transfer is pending. If no other data transfer is pending, the data is
held indefinitely.
187
t3
nAUTOFD
t4
PDATA<7:0>
t2
t1
t7
t8
nSTROBE
BUSY
t6
t5
t6
FIGURE 17 - ECP PARALLEL PORT FORWARD TIMING
NAME
DESCRIPTION
MIN
0
TYP
MAX
UNITS
60
ns
t1
nAUTOFD Valid to nSTROBE Asserted
t2
PDATA Valid to nSTROBE Asserted
0
60
ns
t3
BUSY Deasserted to nAUTOFD Changed
(Notes 1,2)
80
180
ns
t4
BUSY Deasserted to PDATA Changed (Notes 1,2)
80
180
ns
t5
nSTROBE Deasserted to Busy Asserted
0
ns
t6
nSTROBE Deasserted to Busy Deasserted
0
ns
t7
BUSY Deasserted to nSTROBE Asserted (Notes 1,2)
80
200
ns
t8
BUSY Asserted to nSTROBE Deasserted (Note 2)
80
180
ns
Note 1: Maximum value only applies if there is data in the FIFO waiting to be written out.
Note 2: BUSY is not considered asserted or deasserted until it is stable for a minimum of 75 to 130
ns.
188
t2
PDATA<7:0>
t1
t5
t6
nACK
t4
t3
t4
nAUTOFD
FIGURE 18 - ECP PARALLEL PORT REVERSE TIMING
NAME
DESCRIPTION
MIN
TYP
MAX
UNITS
t1
PDATA Valid to nACK Asserted
0
ns
t2
nAUTOFD Deasserted to PDATA Changed
0
ns
t3
nACK Asserted to nAUTOFD Deasserted
(Notes 1,2)
80
200
ns
t4
nACK Deasserted to nAUTOFD Asserted (Note 2)
80
200
ns
t5
nAUTOFD Asserted to nACK Asserted
0
ns
t6
nAUTOFD Deasserted to nACK Deasserted
0
ns
Note 1: Maximum value only applies if there is room in the FIFO and terminal count has not been
received. ECP can stall by keeping nAUTOFD low.
Note 2: nACK is not considered asserted or deasserted until it is stable for a minimum of 75 to 130
ns.
189
DATA
0
1
0
1
0
0
1
1
0
1
1
t2
t1
t2
t1
IRRX
n IRRX
Pa rameter
t1
t1
t1
t1
t1
t1
t1
t2
t2
t2
t2
t2
t2
t2
Pulse W idth at 1 15kba ud
Pulse Wid th at 57.6kba ud
Pulse Wid th at 38.4kba ud
Pulse Wid th at 19.2kba ud
Pu lse Wi dth a t 9.6kba ud
Pu lse Wi dth a t 4.8kba ud
Pu lse Wi dth a t 2.4kba ud
Bit Time at 1 15kba ud
Bit Time at 57.6kba ud
Bit Time at 38.4kba ud
Bit Time at 19.2kba ud
Bi t Time a t 9.6kba ud
Bi t Time a t 4.8kba ud
Bi t Time a t 2.4kba ud
min
typ
m ax
units
1.4
1.4
1.4
1.4
1.4
1.4
1.4
1.6
3.22
4.8
9.7
19.5
39
78
8.68
17.4
26
52
1 04
2 08
4 16
2.71
3.69
5.53
1 1.07
2 2.13
4 4.27
8 8.55
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
No te s:
1. Recei ve Pu lse Detection C ri te ria: A re ceived p ulse is consi dered d etecte d if the
receive d p ulse is a minimum o f 1.41µ s.
2. IR RX: L5, CRF1 Bit 0 = 1
nIRRX: L5, CRF1 Bi t 0 = 0 (defaul t)
FIGURE 19 - IrDA RECEIVE TIMING
190
DAT A
0
1
0
t2
t1
t2
t1
1
0
0
1
1
1
0
IRT X
n IRT X
Parameter
t1
t1
t1
t1
t1
t1
t1
t2
t2
t2
t2
t2
t2
t2
Pulse Width at 115kbaud
Pulse Width at 57.6kbaud
Pulse Width at 38.4kbaud
Pulse Width at 19.2kbaud
Pulse Width at 9.6kbaud
Pulse Width at 4.8kbaud
Pulse Width at 2.4kbaud
Bit Time at 115kbaud
Bit Time at 57.6kbaud
Bit Time at 38.4kbaud
Bit Time at 19.2kbaud
Bit Time at 9.6kbaud
Bit Time at 4.8kbaud
Bit Time at 2.4kbaud
mi n
typ
max
1.41
1.41
1.41
1.41
1.41
1.41
1.41
1.6
3.22
4.8
9.7
19.5
39
78
8.68
17.4
26
52
104
208
416
2.71
3.69
5.53
11.07
22.13
44.27
88.55
u nits
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
Notes:
1. I rDA @ 115k is HPSIR compatible. IrDA @ 2400 will allow compatibility with HP95LX
and 48SX.
2. IRT X: L5, CRF 1 Bit 1 = 1 (default)
nIRT X: L5, CRF1 Bit 1 = 0
FIGURE 20 - IrDA TRANSMIT TIMING
191
1
DATA
0
1
t1
0
1
0
0
1
1
0
t2
IRRX
n IRRX
t3
t4
t5
t6
MIRRX
nM IRRX
P a ramet er
min
typ
max
units
t1
Modulated Out put Bit Time
t2
Off Bit Time
t3
Modulated Outp ut "On"
0.8
1
1.2
µs
t4
Modulated Out put "Off"
0.8
1
1.2
µs
t5
Modulated Outp ut "On"
0.8
1
1.2
µs
t6
Modulated Out put "Off"
0.8
1
1.2
µs
µs
µs
Note s:
1 . IRRX: L 5, CRF 1 Bit 0 = 1
n IRRX: L5 , CRF1 Bit 0 = 0 (de fault)
M IRRX, nMI RRX are the mod ulate d ou tpu ts
FIGURE 21 - AMPLITUDE SHIFT KEYED IR RECEIVE TIMING
192
1
1
DATA
0
1
t1
0
1
0
0
1
1
0
1
t2
IRTX
n IRTX
t3
t4
t5
t6
MIRTX
n MIRTX
Paramet er
min
t yp
max
units
t1
M odulated Out put Bit Time
t2
Off Bit Time
t3
M odulated Outp ut "On"
0.8
1
1.2
µs
t4
M odulated Outp ut "Off"
0.8
1
1.2
µs
t5
M odulated Outp ut "On"
0.8
1
1.2
µs
t6
M odulated Outp ut "Off"
0.8
1
1.2
µs
µs
µs
Note s:
1 . IRTX:
L5, CRF1 Bit 1 = 1 (def ault)
nI RTX: L 5, CRF1 Bit 1 = 0
MIRTX, nM IRTX a re the mod ulate d ou tpu ts
FIGURE 22 - AMPLITUDE SHIFT KEYED IR TRANSMIT TIMING
193
1
D
D1
E
E1
e
W
A
A2
TD/TE
H
0.10
-CDIM
A
A1
A2
D
D1
E
E1
H
L
L1
e
0
W
TD(1)
TE(1)
TD(2)
TE(2)
0
A1
MIN
MAX
2.80
3.15
0.1
0.45
2.57
2.87
23.4
24.15
19.9
20.1
17.4
18.15
13.9
14.1
0.1
0.2
0.65
0.95
1.8
2.6
0.65 BSC
0°
12°
.2
.4
21.8
22.2
15.8
16.2
22.21
22.76
16.27
16.82
L
L1
MAX
MIN
.124
.110
.018
.004
.113
.101
.951
.921
.791
.783
.715
.685
.555
.547
.008
.004
.037
.026
.102
.071
.0256 BSC
0°
12°
.008
.016
.858
.874
.622
.638
.874
.896
.641
.662
Notes:
1) Coplanarity is 0.100mm (.004") maximum.
2) Tolerance on the position of the leads is
0.200mm (.008") maximum.
3) Package body dimensions D1 and E1 do not
include the mold protrusion. Maximum mold
protrusion is 0.25mm (.010").
4) Dimensions TD and TE are important for testing
by robotic handler. Only above combinations of (1)
or (2) are acceptable.
5) Controlling dimension: millimeter. Dimensions
in inches for reference only and not necessarily
accurate.
FIGURE 23 - 100 PIN QFP PACKAGE OUTLINE
194
FDC37B77x ERRATA SHEET
PAGE
10
10
125
130
137
139
143
152
SECTION/FIGURE/ENTRY
Notes 5, 6 and 7
Buffer Type Descriptions
Table 51
PME Support
Note 3
Note 1
Notes 2 and 3
Table 62/Note
195
CORRECTION
See Italicized Text
See Italicized Text
See Italicized Text
See Italicized Text
See Italicized Text
See Italicized Text
See Italicized Text
See Italicized Text
DATE
REVISED
12/9/97
12/9/97
12/9/97
12/9/97
12/9/97
12/9/97
12/9/97
12/9/97
© 2000 STANDARD MICROSYSTEMS CORPORATION (SMSC)
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(631) 435-6000
FAX (631) 273-3123
Standard Microsystems is a registered trademark of Standard Microsystems Corporation, and SMSC, Ultra I/O, ChiProtect and MultiMode are trademarks of Standard Microsystems Corporation. Product names and company names are the trademarks of their
respective holders. Circuit diagrams utilizing SMSC products are included as a means of illustrating typical applications; consequently
complete information sufficient for construction purposes is not necessarily given. Although the information has been checked and is
believed to be accurate, no responsibility is assumed for inaccuracies. SMSC reserves the right to make changes to specifications and
product descriptions at any time without notice. Contact your local SMSC sales office to obtain the latest specifications before placing
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FDC37B77x Rev. 03/24/2000