AMD AM85C30-8 Enhanced serial communications controller Datasheet

FINAL
Am85C30
Enhanced Serial Communications Controller
DISTINCTIVE CHARACTERISTICS
■ Fastest data rate of any Am8530
— 8.192 MHz / 2.048 Mb/s
— 10 MHz / 2.5 Mb/s
— 16.384 MHz / 4.096 Mb/s
■ Low-power CMOS technology
■ Pin and function compatible with other NMOS
and CMOS 8530s
■ Easily interfaced with most CPUs
— Compatible with non-multiplexed bus
■ Many enhancements over NMOS Am8530H
— Allows Am85C30 to be used more effectively in
high-speed applications
— Improves interface capabilities
■ Two independent full-duplex serial channels
■ Asynchronous mode features
— Programmable stop bits, clock factor, character
length and parity
— Break detection/generation
— Error detection for framing, overrun, and parity
■ Synchronous mode features
Advanced
Micro
Devices
— Programmable CRC generators and checkers
— SDLC/HDLC support includes frame control,
zero insertion and deletion, abort, and residue
handling
■ Enhanced SCC functions support high-speed
frame reception using DMA
—
—
—
—
14-bit byte counter
10 × 19 SDLC/HDLC Frame Status FIFO
Independent Control on both channels
Enhanced operation does not allow special
receive conditions to lock the 3-byte DATA
FIFO when the 10 × 19 FIFO is enabled
■ Local Loopback and Auto Echo modes
■ Internal or external character synchronization
■ 2-Mb/s FM encoding transmit and receive
capability using internal DPLL for 16.384-MHz
product
■ Internal synchronization between RxC to PCLK
and TxC to PCLK
— This allows the user to eliminate external synchronization hardware required by the NMOS
device when transmitting or receiving data at
the maximum rate of 1/4 PCLK frequency
— Supports IBM BISYNC, SDLC, SDLC Loop,
HDLC, and ADCCP Protocols
GENERAL DESCRIPTION
AMD’s Am85C30 is an enhanced pin-compatible version of the popular Am8530H Serial Communications
Controller. The Enhanced Serial Communications
Controller (ESCC) is a high-speed, low-power, multiprotocol communications peripheral designed for use
with 8- and 16-bit microprocessors. It has two independent,full-duplex channels and functions as a serial-toparallel, parallel-to-serial converter/controller. AMD’s
proprietary enhancements make the Am85C30 easier
to interface and more effective in high-speed applications due to a reduction in software burden and the elimination of the need for some external glue logic.
The Am85C30 is easy to use due to a variety of sophisticated internal functions, including on-chip baud rate
generators, digital phase-locked loops, and crystal
oscillators, which dramatically reduce the need for external logic. The device can generate and check CRC
codes in any SYNC mode, and can be programmed to
check data integrity in various modes. The ESCC also
has facilities for modem controls in both channels. In applications where these controls are not needed, the modem controls can be used for general-purpose I/O.
This versatile device supports virtually any serial data
transfer application such as networks, modems, cassettes, and tape drivers. The ESCC is designed for nonmultiplexed buses and is easily interfaced with most
CPUs, such as 80188, 80186, 80286, 8080, Z80, 6800,
68000 and MULTIBUS.
Publication# 10216 Rev. F
Issue Date: June 1993
Amendment /0
AMD
Enhancements that allow the Am85C30 to be used
more effectively in high-speed applications include:
Other enhancements to improve the Am85C30 interface capabilities include:
■ A 10 × 19 bit SDLC/HDLC frame status FIFO array
■ Write data valid setup time to falling edge of WR
requirement eliminated
■ A 14-bit SDLC/HDLC frame byte counter
■ Reduced INT response time
■ Automatic SDLC/HDLC opening frame flag
transmission
■ Reduced access recovery time (tRC) to 3 PCLK
best case (3 1/2 PCLK worst case)
■ TxD pin forced High in SDLC NRZI mode after
closing flag
■ Improved Wait timing
■ Automatic SDLC/HDLC Tx underrun/EOM flag
reset
■ Write Registers WR3, WR4, WR5, and WR10
made readable
■ Automatic SDLC/HDLC Tx CRC generator reset/
preset
■ Lower priority interrupt masking without INTACK
■ Complete SDLC/HDLC CRC character reception
■ RTS synchronization to closing SDLC/HDLC flag
DTR/REQ deactivation delay significantly reduced
■ External PCLK to RxC or TxC synchronization
requirement eliminated for PCLK divide-by-four
operation
BLOCK DIAGRAM
Baud
Rate
Generator
TxDA
Transmitter
Receiver
RxDA
RTxCA
TRxCA
Internal
Control
Logic
Data
8
Control
5
10×19 Bit
Frame
Status
FIFO
Channel
A
Registers
Control
Logic
CPU
Bus VO
Channel A
Internal Bus
Interrupt
Control
Logic
Interrupt
Control Lines
Channel
B
Registers
DTR/REQA
SYNCA
W/REQA
RTSA
CTSA
DCDA
TxDB
RxDB
RTxCB
TRxCB
DTR/REQB
SYNCB
W/REQB
RTSB
CTSB
DCDB
Channel B
+5 V GND PCLK
10216F-1
RELATED AMD PRODUCTS
Part No.
Am7960
80186
80286, 80C286
2
Description
Part No.
Description
Coded Data Transceiver
Highly Integrated 16-Bit
Microprocessor
High-Performance 16-Bit
Microprocessor
Am9517A
5380, 53C80
80188
DMA Controller
SCSI Bus Controller
Highly Integrated 8-Bit
Microprocessor
High-Performance 32-Bit
Microprocessor
Am386
Am85C30
AMD
CONNECTION DIAGRAMS
Top View
WR
PLCC, LCC
INT
DIP
3
38
D4
D7
4
37
D6
IEO
7
39
A/B
8
38
CE
9
37
D/C
6
5 4
RD
D5
D4
D6
D2
D2
39
D0
2
D1
D0
D3
40
D5
1•
D3
D7
D1
1 44 43 42 41 40
3 2
INT
5
36
RD
IEI
IEO
6
35
WR
INTACK
IEI
7
34
A/B
+5 V
10
36
NC
INTACK
8
33
11
35
GND
9
CE
D/C
W/REQA
32
SYNCA
12
34
W/REQB
RTxCA
13
33
SYNCB
RxDA
14
32
RTxCB
TRxCA
15
31
RxDB
TxDA
16
30
TRxCB
17
29
TxDB
RTxCA
12
29
SYNCB
RxDA
13
28
RTxCB
TRxCA
14
27
RxDB
TxDA
15
26
TRxCB
DTR/REQA
16
25
TxDB
RTSA
17
24
DTR/REQB
DCDB
Note:
Pin 1 is marked for orientation.
10216F-2
NC
21
DTR/REQB
20
RTSB
CTSB
PCLK
CTSB
RTSB
22
DCDB
23
19
PCLK
18
18 19 20 21 22 23 24 25 26 27 28
DCDA
CTSA
DCDA
NC
CTSA
GND
W/REQB
RTSA
Am85C30
NC
11
30
31
10
DTR/REQA
+5 V
W/REQA
SYNCA
10216F-3
LOGIC SYMBOL
Data
Bus
Bus Timing
and Reset
8
D7–D0
TxDA
RxDA
RD
TRxCA
RTxCA
SYNCA
W/REQA
DTR/REQA
RTSA
CTSA
DCDA
WR
A/B
Control
CE
D/C
Interrupt
TxDB
RxDB
INT
INTACK
IEI
IE0
TRxCB
RTxCB
SYNCB
W/REQB
DTR/REQB
RTSB
CTSB
DCDB
Serial
Data
Channel
Clocks
Channel
Controls
for
Modem,
DMA, or
Other
Serial
Data
Channel
Clocks
Channel
Controls
for
Modem,
DMA, or
Other
10216F-4
+5 V GND
PCLK
Am85C30
3
AMD
ORDERING INFORMATION
Commodity Products
AMD commodity products are available in several packages and operating ranges. The order number (Valid Combination) is
formed by a combination of:
AM85C30
-10
P
C
OPTIONAL PROCESSING
Blank = Standard Processing
TEMPERATURE RANGE
C = Commercial (0 to +70°C)
PACKAGE TYPE
P = 40-Pin Plastic DIP (PD 040)
J = 44-Pin Plastic Leaded Chip Carrier (PL 044)
SPEED OPTION
-8 = 8.192 MHz
-10 = 10 MHz
-16 = 16.384 MHz
DEVICE NUMBER/DESCRIPTION
Am85C30
Enhanced Serial Communications Controller
Valid Combinations
Valid Combinations list configurations planned to
be supported in volume for this device. Consult
the local AMD sales office to confirm availability of
specific valid combinations and check on newly
released combinations.
Valid Combinations
AM85C30-8
AM85C30-10
AM85C30-16
4
PC, JC
Am85C30
AMD
ORDERING INFORMATION
Industrial Products
AMD industrial products are available in several packages and operating ranges. The order number (Valid Combination) is
formed by a combination of:
AM85C30
-10
J
I
OPTIONAL PROCESSING
Blank = Standard Processing
TEMPERATURE RANGE
I = Industrial (-40 to +85°C)
PACKAGE TYPE
J = 44-Pin Leadless Chip Carrier (PL 044)
SPEED OPTION
-10 = 10 MHz
-16 = 16.384 MHz
DEVICE NUMBER/DESCRIPTION
Am85C30
Enhanced Serial Communications Controller
Valid Combinations
Valid Combinations list configurations planned to
be supported in volume for this device. Consult
the local AMD sales office to confirm availability of
specific valid combinations and check on newly
released combinations.
Valid Combinations
AM85C30-10
AM85C30-16
JI
Am85C30
5
AMD
MILITARY ORDERING INFORMATION
APL Products
AMD products for Aerospace and Defense applications are available in several packages and operating ranges. APL (Approved
Products List) products are fully compliant with MIL-STD-883 requirements. The order number (Valid Combination) is formed by a
combination of:
AM85C30
B
-10
U
A
LEAD FINISH
A = Hot Solder Dip
PACKAGE TYPE
U = 44-Pin Leadless Chip Carrier (CL 044)
Q = 40-Pin Ceramic DIP (CD 040)
DEVICE CLASS
/B = Class B
SPEED OPTION
-8 = 8.192 MHz
-10 = 10 MHz
-16 = 16.384 MHz
DEVICE NUMBER/DESCRIPTION
Am85C30
Enhanced Serial Communications Controller
Valid Combinations
AM85C30-8
AM85C30-10
AM85C30-16
6
BQA, BUA
Valid Combinations
Valid Combinations list configurations planned to
be supported in volume for this device. Consult
the local AMD sales office to confirm availability of
specific valid combinations and check on newly
released combinations.
Am85C30
AMD
PIN DESCRIPTION
Bus Timing and Reset
RD
used as general-purpose input pins. Both are Schmitttrigger buffered to accommodate slow rise-time signals.
The SCC detects pulses on these pins and may interrupt
the CPU on both logic level transitions.
Read (Input; Active Low)
This signal indicates a Read operation and, when the
SCC is selected, enables the SCC’s bus drivers. During
the Interrupt Acknowledge cycle, this signal gates the
interrupt vector onto the bus if the SCC is the highest priority device requesting an interrupt.
WR
Write (Input; Active Low)
When the SCC is selected, this signal indicates a Write
operation. The coincidence of RD and WR is interpreted
as a reset.
Channel Clocks
RTxCA, RTxCB
Receive/Transmit Clocks (Inputs; Active Low)
These pins can be programmed in several different
modes of operation. In each channel, RTxC may supply
the receive clock, the transmit clock, the clock for the
baud rate generator, or the clock of the digital phaselocked loop. These pins can also be programmed for
use with the respective SYNC pins as a crystal oscillator. The receive clock may be 1, 16, 32, or 64 times the
data rate in asynchronous modes.
DTR/REQA, DTR/REQB
Data Terminal Ready/Request
(Outputs; Active Low)
These outputs follow the inverted state programmed
into the DTR bit in WR5. They can also be used as
general-purpose outputs or as Request Lines for a DMA
controller.
RTSA, RTSB
Request to Send (Outputs; Active Low)
When the Request to Send (RTS) bit in Write Register 5
is set, the RTS signal goes Low. When the RTS bit is reset in the asynchronous mode and Auto Enable is on,
the signal goes High after the transmitter is empty. In
SYNC mode, or in asynchronous mode with Auto Enable off, the RTS pins strictly follow the inverted state of
the RTS bit. Both pins can be used as general-purpose
outputs.
In SDLC mode, the AUTO RTS RESET enhancement
described later in this document brings RTS High after
the last 0 of the closing flag leaves the TxD pin.
SYNCA, SYNCB
TRxCA, TRxCB
Synchronization (Inputs/Outputs; Active Low)
Transmit/Receive Clocks
(Inputs/Outputs; Active Low)
These pins can be programmed in several different
modes of operation. TRxC may supply the receive clock
or the transmit clock in the input mode or supply the output of the digital phase-locked loop, the crystal oscillator, the baud rate generator, or the transmit clock in the
output mode.
Channel Controls for Modem, DMA,
or Other
CTSA, CTSB
Clear to Send (Inputs; Active Low)
If these pins are programmed as Auto Enables, a Low
on these inputs enables their respective transmitters. If
not programmed as Auto Enables, they may be used as
general-purpose inputs. Both inputs are Schmitt-trigger
buffered to accommodate slow rise-time inputs. The
SCC detects pulses on these inputs and may interrupt
the CPU on both logic level transitions.
DCDA, DCDB
Data Carrier Detect (Inputs; Active Low)
These pins function as receiver enables if they are programmed as Auto Enables; otherwise, they may be
These pins can act either as inputs, outputs, or part of
the crystal oscillator circuit. In the Asynchronous Receive mode (crystal oscillator option not selected), these
pins are inputs similar to CTS and DCD. In this mode,
transitions on these lines affect the state of the Sync/
Hunt status bits in Read Register 0 but have no other
function.
In External Synchronization mode with the crystal
oscillator not selected, these lines also act as inputs.
In this mode, SYNC must be driven Low two receive
clock cycles after the last bit in the SYNC character is
received. Character assembly begins on the rising edge
of the receive clock immediately preceding the activation of SYNC.
In the Internal Synchronization mode (Monosync and
Bisync) with the crystal oscillator not selected, these
pins act as outputs and are active only during the part of
the receive clock cycle in which SYNC characters are
recognized. The SYNC condition is not latched, so
these outputs are active each time a SYNC pattern is
recognized (regardless of character boundaries). In
SDLC mode, these pins act as outputs and are valid on
receipt of a flag.
Am85C30
7
AMD
W/REQA, W/REQB
Wait/Request (Outputs; Open drain when programmed for a Wait function, driven High or Low
when programmed for a Request function)
These dual-purpose outputs may be programmed as
Request lines for a DMA controller or as Wait lines to
synchronize the CPU to the SCC data rate. The reset
state is Wait.
Control
A/B
interrupt (interrupt acknowledge cycle only). IEO is connected to the next lower priority device’s IEI input and
thus inhibits interrupts from lower priority devices.
INT
Interrupt Request (Output; Active Low,
Open Drain)
This signal is activated when the SCC requests an
interrupt.
INTACK
Interrupt Acknowledge (Input; Active Low)
Channel A/Channel B Select (Input)
This signal selects the channel in which the Read or
Write operation occurs.
CE
Chip Enable (Input; Active Low)
This signal indicates an active interrupt acknowledge
cycle. During this cycle, the SCC interrupt daisy chain
settles. When RD becomes active, the SCC places an
interrupt vector on the data bus (if IEI is High). INTACK
is latched by the rising edge of PCLK.
This signal selects the SCC for a Read or Write
operation.
Serial Data
RxDA, RxDB
D/C
Receive Data (Inputs; Active High)
Data/Control Select (Input)
These input signals receive serial data at standard TTL
levels.
This signal defines the type of information transferred to
or from the SCC. A High means data is transferred; a
Low indicates a command is transferred.
TxDA, TxDB
Transmit Data (Outputs; Active High)
Data Bus
D7 –D0
These output signals transmit serial data at standard
TTL levels.
Data Bus (Input/Output; Three State)
Miscellaneous
GND
These lines carry data and commands to and from the
SCC.
Ground
Interrupt
IEI
PCLK
Interrupt Enable In (Input; Active High)
This is the master SCC clock used to synchronize internal signals. PCLK is not required to have any phase
relationship with the master system clock. PCLK is a
TTL- level signal. Maximum transmit rate is 1/4 PCLK.
Clock (Input)
IEI is used with IEO to form an interrupt daisy chain
when there is more than one interrupt-driven device. A
High IEI indicates that no other higher priority device has
an interrupt under service or is requesting an interrupt.
VCC
+ 5 V Power Supply
IEO
Interrupt Enable Out (Output; Active High)
IEO is High only if IEI is High and the CPU is not servicing an SCC interrupt or the SCC is not requesting an
8
Am85C30
AMD
ARCHITECTURE
The ESCC internal structure includes two full-duplex
channels, two 10 × 19 bit SDLC/HDLC frame status
FIFOs, two baud rate generators, internal control and interrupt logic, and a bus interface to a non-multiplexed
bus. Associated with each channel are a number of
Read and Write registers for mode control and status information, as well as logic necessary to interface with
modems or other external devices (see Logic Symbol).
The logic for both channels provides formats, synchronization, and validation for data transferred to and from
the channel interface. The modem control inputs are
monitored by the control logic under program control. All
of the modem control signals are general-purpose in nature and can optionally be used for functions other than
modem control.
The register set for each channel includes ten control
(Write) registers, two SYNC character (Write) registers,
and four status (Read) registers. In addition, each baud
rate generator has two (Read/Write) registers for holding the time constant that determines the baud rate. Finally, associated with the interrupt logic is a Write
register for the interrupt vector accessible through either
channel, a Write-only Master Interrupt Control register,
and three Read registers: one containing the vector with
status information (Channel B only), one containing the
vector without status (A only), and one containing the interrupt pending bits (A only).
The registers for each channel are designated as
follows:
WR0–WR15—Write Registers 0 through 15. An additional Write register, WR7 Prime (WR7′), is available for
enabling or disabling additional SDLC/HDLC enhancements if bit D0 of WR15 is set.
RR0–RR3, RR10, RR12, RR13, RR15—Read Registers 0 through 3, 10, 12, 13, and 15.
If bit D2 of WR15 is set, then two additional Read registers, RR6 and RR7, are available. These registers are
used with the 10 × 19 bit Frame Status FIFO.
Table 1 lists the functions assigned to each Read
and Write register. The ESCC contains only one
WR2 and WR9, but they can be accessed by either
channel. All other registers are paired (one for
each channel).
Baud
Rate
Generator
Internal
Control
Logic
Data
Control
8
CPU
Bus VO
Channel
A
Registers
Internal Bus
TxDA
Transmitter
Receiver
10×19 Bit
Frame
Status
FIFO
Channel A
Interrupt
Control
Logic
RTxCA
TRxCA
SYNCA
Control
Logic
5
Interrupt
Control
Lines
RxDA
Channel
B
Registers
RTSA
CTSA
DCDA
TxDB
RxDB
RTxCB
TRxCB
Channel B
SYNCB
RTSB
CTSB
DCDB
+5 V GND PCLK
10216F-5
Figure 1. Block Diagram of ESCC Architecture
Am85C30
9
AMD
Data Path
The transmit and receive data path illustrated in Figure 2
is identical for both channels. The receiver has three
8-bit buffer registers in a FIFO arrangement, in addition
to the 8-bit receive shift register. This scheme creates
additional time for the CPU to service an interrupt at the
beginning of a block of high-speed data. Incoming data
are routed through one of several paths (data or CRC)
depending on the selected mode (the character length
in asynchronous modes also determines the data path).
The transmitter has an 8-bit transmit data buffer register
loaded from the internal data bus and a 20-bit transmit
shift register that can be loaded either from the synccharacter registers or from the transmit data register.
Depending on the operational mode, outgoing data are
routed through one of four main paths before they are
transmitted from the Transmit Data output (TxD).
Table 1. Read and Write Register Functions
Read Register Functions
Write Register Functions
Write Register Functions
RR0
Transmit/Receive buffer status and External
status
RR1
Special Receive Condition status
(also 10 × 19 bit FIFO Frame Reception Status if
WR15 bit D2 is set)
RR2
Modified interrupt vector
(Channel B only)
Unmodified interrupt vector
(Channel A only)
RR3
Interrupt Pending bits
(Channel A only)
RR6
LSB Byte Count (14-bit counter)
(if WR15 bit D2 set)
RR7
MSB Byte Count (14-bit counter)
and 10 × 19 bit FIFO Status (if WR15 bit D2 is set)
RR8
Receive buffer
RR10 Miscellaneous XMTR, RCVR status
RR12 Lower byte of baud rate generator time constant
RR13 Upper byte of baud rate generator time constant
RR15 External/Status interrupt information
WR0
10
WR1
WR2
WR3
WR4
WR5
WR6
WR7
WR7′
WR8
WR9
WR10
WR11
WR12
WR13
WR14
WR15
Am85C30
Command Register, Register Pointers CRC
initialize, initialization commands for the various
modes, shift right/shift left command
Interrupt conditions and data transfer mode
definition
Interrupt vector (accessed through either channel)
Receive parameters and control
Transmit/Receive miscellaneous parameters and
modes
Transmit parameters and controls
Sync character or SDLC address field
Sync character or SDLC flag
SDLC/HDLC enhancements (if bit D0 of WR15 is
set)
Transmit buffer
Master interrupt control and reset (accessed
through either channel)
Miscellaneous transmitter/receiver control bits,
data encoding
Clock mode control, Rx and Tx clock source
Lower byte of baud rate generator time constant
Upper byte of baud rate generator time constant
Miscellaneous control bits, DPLL control
External/Status interrupt control
AMD
Am85C30
11
AMD
DETAILED DESCRIPTION
The functional capabilities of the ESCC can be described from two different points of view: as a data communications device, it transmits and receives data in a
wide variety of data communications protocols; as a microprocessor peripheral, it interacts with the CPU and
provides vectored interrupts and handshaking signals.
Data Communications Capabilities
The ESCC provides two independent full-duplex
channels programmable for use in any common
asynchronous or SYNC data-communication protocol.
Figure 3 and the following description briefly detail these
protocols.
Asynchronous Modes
Transmission and reception can be accomplished independently on each channel with 5 to 8 bits per character,
plus optional even or odd parity. The transmitters can
supply 1, 1 1/2, or 2 stop bits per character and can provide a break output at any time. The receiver breakdetection logic interrupts the CPU both at the start and at
the end of a received break. Reception is protected from
spikes by a transient spike-rejection mechanism that
checks the signal one-half a bit time after a Low level is
detected on the receive data input. If the Low does not
persist (as in the case of a transient), the character assembly process does not start.
Framing errors and overrun errors are detected and
buffered together with the partial character on which
they occur. Vectored interrupts allow fast servicing of
error conditions using dedicated routines. Furthermore,
a built-in checking process avoids the interpretation of
framing error as a new start bit; a framing error results in
the addition of one-half a bit time to the point at which the
search for the next start bit begins.
Synchronous Modes
The ESCC supports both byte-oriented and bit-oriented
synchronous communication. SYNC byte-oriented protocols can be handled in several modes, allowing character synchronization with a 6-bit or 8-bit SYNC
character (Monosync), any 12-bit or 16-bit SYNC pattern (Bisync), or with an external SYNC signal. Leading
SYNC characters can be removed without interrupting
the CPU.
5- or 7-bit SYNC characters are detected with 8- or
16-bit patterns in the ESCC by overlapping the larger
pattern across multiple incoming SYNC characters as
shown in Figure 4.
CRC checking for Synchronous byte-oriented modes is
delayed by one character time so that the CPU may disable CRC checking on specific characters. This permits
the implementation of protocols, such as IBM BISYNC.
Both CRC-16 (X16 + X15 + X2 + 1) and CCITT (X16 + X12 +
X5 + 1) error-checking polynomials are supported.
Either polynomial may be selected in BISYNC and
MONO-SYNC modes. Users may preset the CRC generator and checker to all 1s or all 0s. The ESCC also provides a feature that automatically transmits CRC data
when no other data are available for transmission. This
allows for high-speed transmissions under DMA control
Parity
Stop
Start
Marking Line
The ESCC does not require symmetric transmit and
receive clock signals—a feature allowing use of the
wide variety of clock sources. The transmitter and receiver can handle data at a rate of 1, 1/16, 1/32, or 1/64
of the clock rate supplied to the receive and transmit
clock inputs. In asynchronous modes, the SYNC pin
may be programmed as an input used for functions,
such as monitoring a ring indicator.
Data
Data
Data
Marking Line
Asynchronous
Sync
Data
Data
CRC1
CRC2
Data
CRC1
CRC2
Data
CRC1
CRC2
CRC1
CRC2
Monosync
Sync
Sync
Data
Signal
Bisync
Data
External Sync
Flag
Address
Information
SDLC/HDLC × 25
Figure 3. SCC Protocols
12
Am85C30
Flag
10216F-7
AMD
5 Bits
Sync
Sync
Sync
Data
Data
Data
Data
8 Bits
16 Bits
10216F-8
Figure 4. Detecting 5- or 7-Bit Synchronous Characters
with no need for CPU intervention at the end of a message. When there are no data or CRC to send in SYNC
modes, the transmitter inserts 6-, 8-, or 16-bit SYNC
characters, regardless of the programmed character
length.
The ESCC supports SYNC bit-oriented protocols, such
as SDLC and HDLC, by performing automatic flag sending, zero-bit insertion, and CRC generation. A special
command can be used to abort a frame in transmission.
At the end of a message, the ESCC automatically transmits the CRC and trailing flag when the transmitter underruns. The transmitter may also be programmed to
send an idle line consisting of continuous flag characters or a steady marking condition.
If a transmit underrun occurs in the middle of a message, an external/status interrupt warns the CPU of this
status change so that an abort may be issued. The
ESCC may also be programmed to send an abort itself
in case of an underrun, relieving the CPU of this task.
One to 8 bits per character can be sent allowing reception of a message with no prior information about the
character structure in the information field of a frame.
The receiver automatically acquires synchronization on
the leading flag of a frame in SDLC or HDLC and provides a synchronization signal on the SYNC pin (an interrupt can also be programmed). The receiver can be
programmed to search for frames addressed by a single
byte (or 4 bits within a byte) of a user-selected address
or to a global broadcast address. In this mode, frames
not matching either the user-selected or broadcast address are ignored. The number of address bytes can be
extended under software control. For receiving data, an
interrupt on the first received character, or an interrupt
on every character, or on special condition only (end-offrame) can be selected. The receiver automatically deletes all 0s inserted by the transmitter during character
assembly. CRC is also calculated and is automatically
checked to validate frame transmission. At the end of
transmission, the status of a received frame is available
in the status registers. In SDLC mode, the ESCC must
be programmed to use the SDLC CRC polynomial,
but the generator and checker may be preset to all 1s
or all 0s. The CRC is inverted before transmission
and the receiver checks against the bit pattern
0001110100001111.
NRZ, NRZI or FM coding may be used in any 1X mode.
The parity options available in asynchronous modes are
available in synchronous modes.
The ESCC can be conveniently used under DMA control
to provide high-speed reception or transmission. In reception, for example, the ESCC can interrupt the CPU
when the first character of a message is received. The
CPU then enables the DMA to transfer the message to
memory. The ESCC then issues an end-of-frame interrupt and the CPU can check the status of the received
message. Thus, the CPU is freed for other service while
the message is being received. The CPU may also enable the DMA first and have the ESCC interrupt only on
end-of-frame. This procedure allows all data to be transferred via the DMA.
SDLC Loop Mode
The ESCC supports SDLC Loop mode in addition to
normal SDLC. In a SDLC Loop, there is a primary controller station that manages the message traffic flow and
any number of secondary stations. In SDLC Loop mode,
the ESCC performs the functions of a secondary station
while an ESCC operating in regular SDLC mode can act
as a controller (Figure 5).
Controller
Secondary #1
Secondary #3
Secondary #2
Secondary #4
10216F-9
Figure 5. A SDLC Loop
A secondary station in a SDLC Loop is always listening
to the messages being sent around the loop and, in fact,
must pass these messages to the rest of the loop by
retransmitting them with a 1-bit time delay. The secondary station can place its own message on the loop
only at specific times. The controller signals that secondary stations may transmit messages by sending a special character, called an EOP (End of Poll), around the
loop. The EOP character is the bit pattern 11111110.
Because of zero insertion during messages, this bit pattern is unique and easily recognized.
Am85C30
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When a secondary station has a message to transmit
and recognizes an EOP on the line, it changes the last
binary 1 of the EOP to a 0 before transmission. This has
the effect of turning the EOP into a flag sequence. The
secondary station now places its message on the loop
and terminates the message with an EOP. Any secondary stations farther down the loop with messages to
transmit can then append their messages to the message of the first secondary station by the same process.
Any secondary stations without messages to send
merely echo the incoming messages and are prohibited
from placing messages on the loop (except upon recognizing an EOP).
Time Constant Values
for Standard Baud Rates at BR Clock
= 3.9936 MHz
Rate
(Baud)
19200
9600
7200
4800
3600
2400
2000
1800
1200
600
300
150
134.5
110
75
50
SDLC Loop mode is a programmable option in the
ESCC. NRZ, NRZI, and FM coding may all be used in
SDLC Loop mode.
Baud Rate Generator
Each channel in the ESCC contains a programmable
baud rate generator. Each generator consists of two
8-bit time constant registers that form a 16-bit time constant, a 16-bit down counter, and a flip-flop on the output
producing a square wave. On start-up, the flip-flop on
the output is set in a High state, the value in the time constant register is loaded into the counter, and the counter
starts counting down. The output of the baud rate generator toggles upon reaching zero; the value in the time
constant register is loaded into the counter, and the
process is repeated. The time constant may be changed
at any time, but the new value does not take effect until
the next load of the counter.
The output of the baud rate generator may be used as
either the transmit clock, the receive clock, or both. It
can also drive the digital phase-locked loop (see next
section).
If the receive clock or transmit clock is not programmed
to come from the TRxC pin, the output of the baud rate
generator may be echoed out via the TRxC pin.
The following formula relates the time constant to the
baud rate where PCLK or RTxC is the baud rate generator input frequency in Hz. The clock mode is X1, X16,
X32, or X64 as selected in Write Register 4, bits D6 and
D7. Synchronous operation modes should select X1 and
asynchronous should select X16, X32, or X64.
PCLK or RTxC Frequency
Time Constant =
–2
2 (Baud Rate)(Clock Mode)
The following formula relates the time constant to the
baud rate. The baud rate is in bits/second.
Baud Rate =
14
PCLK or RTxC Frequency
2 × (Clock Mode) × (Time Constant + 2)
Time Constant
(decimal/Hex notation)
102
206
275
414
553
830
996
1107
1662
3326
6654
13310
14844
18151
26622
39934
(0066)
(00CE)
(0113)
(019E)
(0229)
(033E)
(03E4)
(0453)
(067E)
(0CFE)
(19FE)
(33FE)
(39FC)
(46E7)
(67FE)
(98FE)
Error
0
0
0.12%
0
0.06%
0
0.04%
0.03%
0
0
0
0
0.0007%
0.0015%
0
0
Digital Phase-Locked Loop
The ESCC contains a digital phase-locked loop (DPLL)
to recover clock information from a data stream with
NRZI or FM encoding. The DPLL is driven by a clock that
is nominally 32 (NRZI) or 16 (FM) times the data rate.
The DPLL uses this clock, along with the data stream, to
construct a clock for the data. This clock may then be
used as the SCC receive clock, the transmit clock,
or both.
For NRZI encoding, the DPLL counts the 32X clock to
create nominal bit times. As the 32X clock is counted,
the DPLL is searching the incoming data stream for
edges (either 1/0 or 0/1). As long as no transitions are
detected, the DPLL output will be free running and its input clock source will be divided by 32, producing an output clock without any phase jitter. Upon detecting a
transition the DPLL will adjust its clock output (during the
next counting cycle) by adding or subtracting a count of
1, thus producing a terminal count closer to the center of
the bit cell. The adding or subtracting of a count of 1 will
produce a phase jitter of ±5.63° on the output of the
DPLL. Because the SCC’s DPLL uses both edges of the
incoming signal to compare with its clock source, the
mark-space ratio (50%) of the incoming signal should
not deviate by more than ±1.5% if proper locking is to
occur.
For FM encoding, the DPLL still counts from 0 to 31, but
with a cycle corresponding to two bit times. When the
DPLL is locked, the clock edges in the data stream
should occur between counts 15 and 16 and between
Am85C30
AMD
counts 31 and 0. The DPLL looks for edges only during a
time centered on the 15/16 counting transition.
The 32X clock for the DPLL can be programmed to
come from either the RTxC input or the output of the
baud rate generator. The DPLL output may be programmed to be echoed out of the SCC via the TRxC pin
(if this pin is not being used as an input).
Crystal Oscillator
When using a crystal oscillator to supply the receive or
transmit clocks to a channel of the SCC, the user should:
1. Select a crystal oscillator that satisfies the following
specifications:
30 ppm @ 25°C
50 ppm over temperatures of –20° to 70°C
5 ppm/yr aging
5-MW drive level
2. Place crystal across RTxC and SYNC pins.
3. Place 30-pF capacitors to ground from both RTxC
and SYNC pins.
4. Set bit D7 of WR11 to 1.
Data Encoding
The ESCC may be programmed to encode and decode
the serial data in four different ways (Figure 6). In NRZ
encoding, a 1 is represented by a High level, and a 0 is
represented by a Low level. In NRZI encoding, a 1 is represented by no change in level, and a 0 is represented
by a change in level. In FM1 (more properly, biphase
mark), a transition occurs at the beginning of every bit
cell. A 1 is represented by an additional transition at the
center of the bit cell, and a 0 is represented by no
Data
1
1
0
additional transition at the center of the bit cell. In FM0
(biphase space), a transition occurs at the beginning of
every bit cell. A 0 is represented by an additional transition at the center of the bit cell, and a 1 is represented by
no additional transition at the center of the bit cell. In addition to these four methods, the ESCC can be used to
decode Manchester (biphase level) data by using the
DPLL in the FM mode and programming the receiver for
NRZ data. Manchester encoding always produces a
transition at the center of the bit cell. If the transition is
0/1, the bit is a 0. If the transition is 1/0, the bit is a 1.
Auto Echo and Local Loopback
The ESCC is capable of automatically echoing everything it receives. This feature is useful mainly in asynchronous modes but works in SYNC and SDLC modes
as well. In Auto Echo mode, TxD is RxD. Auto Echo
mode can be used with NRZI or FM encoding with no additional delay, because the data stream is not decoded
before retransmission. In Auto Echo mode, the CTS input is ignored as a transmitter enable (although transitions on this input can still cause interrupts if
programmed to do so). In this mode, the transmitter is
actually bypassed, and the programmer is responsible
for disabling transmitter interrupts and WAIT/
REQUEST on transmit.
The ESCC is also capable of Local Loopback. In this
mode, TxD is RxD just as in Auto Echo mode. However,
in Local Loopback mode, the internal transmit data is
tied to the internal receive data, and RxD is ignored (except to be echoed out via TxD). The CTS and DCD inputs are also ignored as transmit and receive enables.
However, transitions on these inputs can still cause interrupts. Local Loopback works in asynchronous,
SYNC, and SDLC modes with NRZ, NRZI, or FM coding
of the data stream.
0
1
0
Bit Cell Level
NRZ
High = 1
Low = 0
NRZI
No Change = 1
Change = 0
FM1
(Biphase Mark)
Bit Center Transition
Transition = 1
No Transition = 0
(Biphase Mark)
No Transition = 1
Transition = 0
FM0
Manchester
High Low = 1
Low High = 0
10216F-10
Figure 6. Data Encoding Methods
Am85C30
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AMD
I/O Interface Capabilities
The ESCC offers the choice of Polling, Interrupt (vectored or nonvectored), and Block Transfer modes to
transfer data, status, and control information to and from
the CPU. The Block Transfer mode can be implemented
under CPU or DMA control.
Polling
All interrupts are disabled. Three status registers in the
ESCC are automatically updated whenever any function is performed. For example, end-of-frame in SDLC
mode sets a bit in one of these status registers. The idea
behind polling is for the CPU to periodically read a status
register until the register contents indicate the need for
data to be transferred. Only one register needs to be
read; depending on its contents, the CPU either writes
data, reads data, or continues. Two bits in the register
indicate the need for data transfer. An alternative is a
poll of the Interrupt Pending register to determine the
source of an interrupt. The status for both channels resides in one register.
Interrupts
When an ESCC responds to an Interrupt Acknowledge
signal (INTACK) from the CPU, an interrupt vector may
be placed on the data bus. This vector is written in WR2
and may be read in RR2A or RR2B (Figures 8 and 9).
To speed interrupt response time, the ESCC can modify
3 bits in this vector to indicate status. If the vector is read
in Channel A, status is never included; if it is read in
Channel B, status is always included.
Each of the six sources of interrupts in the ESCC (Transmit, Receive, and External/Status interrupts in both
channels) has 3 bits associated with the interrupt
source: Interrupt Pending (IP), Interrupt Under Service
(IUS), and Interrupt Enable (IE). Operation of the IE bit is
straightforward. If the IE bit is set for a given interrupt
source, then that source can request interrupts. The exception is when the MIE (Master Interrupt Enable) bit in
WR9 is reset and no interrupts may be requested. The
IE bits are write-only.
The other 2 bits are related to the Z-Bus interrupt priority
chain (Figure 7). As a Z-Bus peripheral, the ESCC may
request an interrupt only when no higher priority device
is requesting one, for example, when IEI is High. If the
device in question requests an interrupt, it pulls down
INT. The CPU then responds with INTACK, and the interrupting device places the vector on the A/D bus.
In the SCC, the IP bit signals a need for interrupt servicing. When an IP bit is set to 1 and the IEI input is High,
the INT output is pulled Low, requesting an interrupt. In
the ESCC, if the IE bit is set for an interrupt, then the IP
for that source can never be set. The IP bits are readable
in RR3A.
The IUS bits signal that an interrupt request is being
serviced. If an IUS is set, all interrupt sources of lower
priority in the ESCC and external to the ESCC are prevented from requesting interrupts. The internal interrupt
sources are inhibited by the state of the internal daisy
chain, while lower priority devices are inhibited by the
IEO output of the ESCC being pulled Low and propagated to subsequent peripherals. An IUS bit is set during
an Interrupt Acknowledge cycle if there are no higher
priority devices requesting interrupts.
There are three types of interrupts: Transmit, Receive,
and External/Status. Each interrupt type is enabled under program control with Channel A having higher priority than Channel B, and with Receive, Transmit, and
External/Status interrupts prioritized in that order within
each channel. When the Transmit interrupt is enabled,
the CPU is interrupted when the transmit buffer becomes empty. (This implies that the transmitter must
have had a data character written into it so that it can become empty.) When enabled, the Receive can interrupt
the CPU in one of three ways:
Peripheral
Peripheral
+5 V IEI AD7–AD0 INT INTACK IEO
Interrupt on First Receive Character or Special
Receive condition
Interrupt on all Receive Characters or Special
Receive condition
Interrupt on Special Receive condition only
IEI AD7–AD0 INT INTACK IEO
Peripheral
IEI AD7–AD0 INT INTACK
+5 V
D7–D0
AD7–AD0
INT
INTACK
10216F-11
Figure 7. Z-Bus Interrupt Schedule
16
Am85C30
AMD
Interrupt on First Character or Special Condition and Interrupt on Special Condition Only are typically used with
the Block Transfer mode. A Special Receive Condition
is one of the following: receiver overrun, framing error in
asynchronous mode, end-of-frame in SDLC mode, and
optionally, a parity error. The Special Receive Condition
interrupt is different from an ordinary Receive Character
Available interrupt only in the status placed in the vector
during the Interrupt Acknowledge cycle. In Interrupt on
First Receive Character, an interrupt can occur from
Special Receive Conditions any time after the first
Receive Character Interrupt.
The main function of the External/Status interrupt is to
monitor the signal transitions of the CTS, DCD, and
SYNC pins; however, an External/Status interrupt is
also caused by a Transmit Underrun condition, a zero
count in the baud rate generator, the detection of a
Break (asynchronous mode), Abort (SDLC mode), or
EOP (SDLC Loop mode) sequence in the data stream.
The interrupt caused by the Abort or EOP has a special
feature allowing the ESCC to interrupt when the Abort or
EOP sequence is detected or terminated. This feature
facilitates the proper termination of the current
message, correct initialization of the next message, and
the accurate timing of the Abort condition in external
logic in SDLC mode. In SDLC Loop mode, this feature
allows secondary stations to recognize the wishes of the
primary station to regain control of the loop during a poll
sequence.
CPU/DMA Block Transfer
The SCC provides a Block Transfer mode to accommodate CPU block transfer functions and DMA controllers.
The Block Transfer mode uses the WAIT/REQUEST
output in conjunction with the Wait/Request bits in WR1.
The WAIT/REQUEST output can be defined under software control as a WAIT line in the CPU Block Transfer
mode or as a REQUEST line in the DMA Block Transfer
mode.
To a DMA controller, the ESCC REQUEST output indicates that the ESCC is ready to transfer data to or from
memory. To the CPU, the WAIT line indicates that the
SCC is not ready to transfer data, thereby requesting
that the CPU extend the I/O cycle. The DTR/REQUEST
can be used as the transmit request line, thus allowing
full-duplex operation under DMA control.
PROGRAMMING INFORMATION
Each channel has fifteen Write registers that are individually programmed from the system bus to configure
the functional personality of each channel. Each channel also has eight Read registers from which the system
can read Status, Baud rate, or Interrupt information.
On the Am85C30, only four data registers (Read and
Write for Channels A and B) are directly selected by a
High on the D/C input and the appropriate levels on the
RD, WR, and A/B pins. All other registers are addressed
indirectly by the content of Write Register 0 in conjunction with a Low on the D/C input and the appropriate levels on the RD, WR, and A/B pins. If bit D3 in WR0 is 1 and
bits 5 and 6 are 0, then bits 0, 1, and 2 address the higher
registers 8 through 15. If bits 4, 5, and 6 contain a different code, bits 0, 1, and 2 address the lower registers 0
through 7 as shown in Table 2.
Writing to or reading from any register except RR0,
WR0, and the data registers thus involves two
operations:
First, write the appropriate code into WR0, then follow
this by a Write or Read operation on the register thus
specified. Bits 0 through 4 in WR0 are automatically
cleared after this operation, so that WR0 then points to
WR0 or RR0 again.
Channel A/Channel B selection is made by the A/B input
(High = A, Low = B).
The system program first issues a series of commands
to initialize the basic mode of operation. This is followed
by other commands to qualify conditions within the selected mode. For example, the asynchronous mode,
character length, clock rate, number of stop bits, even or
odd parity might be set first. Then the interrupt mode
would be set and, finally, receiver or transmitter enable.
Am85C30
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AMD
Table 2. Register Addressing
D/C
“Point High”
Code In WR0:
High
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Either Way
Not True
Not True
Not True
Not True
Not True
Not True
Not True
Not True
True
True
True
True
True
True
True
True
D2, D1, D0
In WR0:
X
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
Read Registers
The ESCC contains eight Read registers [actually nine,
counting the receive buffer (RR8) in each channel]. Four
of these may be read to obtain status information (RR0,
RR1, RR10, and RR15). Two registers (RR12 and
RR13) may be read to learn the baud rate generator
time constant. RR2 contains either the unmodified interrupt vector (Channel A) or the vector modified by status
information (Channel B). RR3 contains the Interrupt
Pending (IP) bits (Channel A). In addition, if bit D2 of
WR15 is set, RR6 and RR7 are available for providing
frame status from the 10 × 19 bit Frame Status FIFO.
Figure 8 shows the formats for each Read register.
The status bits of RR0 and RR1 are carefully grouped to
simplify status monitoring, for example, when the interrupt vector indicates a Special Receive Condition
interrupt, all the appropriate error bits can be
read from a single register (RR1). Please refer to
18
X
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
X
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Write
Register
Read
Register
Data
0
1
2
3
4
5
6
7
Data
9
10
11
12
13
14
15
Data
0
1
2
3
(0)
(1)
(2)
(3)
Data
–
10
(15)
12
13
(10)
15
Am85C30 Technical Manual for detailed descriptions of
the read registers.
Write Registers
The ESCC contains 15 Write registers (16 counting
WR8, the transmit buffer) in each channel. These Write
registers are programmed separately to configure the
functional “personality” of the channels. Two registers
(WR2 and WR9) are shared by the two channels that
can be accessed through either of them. WR2 contains
the interrupt vector for both channels, while WR9 contains the interrupt control bits. In addition, if bit D0 of
WR15 is set, Write Register 7 prime (WR7′) is available
for programming additional SDLC/HDLC enhancements. When bit D0 of WR15 is set, executing a write to
WR7 actually writes to WR7′ to further enhance the
functional “personality” of each channel. Figure 8 shows
the format of each Write register.
Am85C30
AMD
Read Register 0
Read Register 3
D7 D6 D5 D4 D3 D2 D1 D0
D7 D6 D5 D4 D3 D2 D1 D0
Channel B EXT STAT IP*
Channel B Tx IP*
Channel B Rx IP*
Channel A EXT STAT IP*
Channel A Tx IP*
Channel A Rx IP*
0
0
Rx Character Available
Zero Count
Tx Buffer Empty
DCD
SYNC Hunt
CTS
Tx Underrun/EOM
Break Abort
*Always 0 in B Channel
Read Register 1
Read Register 6
D7 D6 D5 D4 D3 D2 D1 D0
D7 D6 D5 D4 D3 D2 D1 D0
BC0
BC1
BC2
BC3
BC4
BC5
BC6
BC7
All Sent
Residue Code 2
Residue Code 1
Residue Code 0
Parity Error
Rx Overrun Error
CRC Framing Error
End-of-Frame (SDLC)
Read Register 2
Read Register 7
D7 D6 D5 D4 D3 D2 D1 D0
D7 D6 D5 D4 D3 D2 D1 D0
V0
V1
V2
V3
V4
V5
V6
V7
BC8
BC9
BC10
BC11
BC12
BC13
FDA*
FOY**
Interrupt Vector*
*Modified in B Channel
14-Bit
LSB Byte
Count
14-Bit
MSB Byte
Count
10 × 19 bit
FIFO Status
*FIFO Data Available Status
**FIFO Overflow Status
10216F-12
Figure 8. Read Register Bit Functions
Am85C30
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AMD
Read Register 10
Read Register 13
D7 D6 D5 D4 D3 D2 D1 D0
D7 D6 D5 D4 D3 D2 D1 D0
TC8
TC9
TC10
TC11
TC12
TC13
TC14
TC15
0
On Loop
0
0
Loop Sending
0
Two Clocks Missing
One Clock Missing
Read Register 12
Read Register 15
D7 D6 D5 D4 D3 D2 D1 D0
D7 D6 D5 D4 D3 D2 D1 D0
TC0
TC1
TC2
TC3
TC4
TC5
TC6
TC7
SDLC/HDLC Enhancement Status*
Zero Count IE
10 × 19 bit FIFO Enable/Disable*
DCD IE
SYNC Hunt IE
CTS IE
Tx Underrun/EOM IE
Break/Abort IE
Lower Byte of
Time Constant
10216F-12
(concluded)
*Added Enhancement
Figure 8. Read Register Bit Functions (continued)
Write Register 0
D7 D6 D5 D4 D3 D2 D1 D0
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
Null Code
Reset Rx CRC Checker
Reset Tx CRC Generator
Reset Tx Underrun/EOM Latch
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
Register
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Null Code
Point High Register Group
Reset Ext/Status Interrupts
Send Abort
Enable Int on Next Rx Character
Reset Tx Int Pending
Error Reset
Reset Highest IUS
0
1
0
1
10216F-13
Figure 9. Write Register Bit Functions
20
Upper Byte of
Time Constant
Am85C30
AMD
Write Register 1
Write Register 4
D7 D6 D5 D4 D3 D2 D1 D0
D7 D6 D5 D4 D3 D2 D1 D0
0
0
1
1
0
1
0
1
Parity Enable
Parity Even/Odd
Ext Int Enable
Tx Int Enable
Parity is Special Condition
Rx Int Disable
Rx Int on First Character or Special Condition
Int on All Rx Characters or Special Condition
Rx Int on Special Condition only
Wait/DMA Request on Receive/Transmit
Wait/DMA Request Function
Wait/DMA Request Enable
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
Sync Modes Enable
1 Stop Bit/Character
1 1/2 Stop Bits/Character
2 Stop Bits/Character
8-Bit Sync Character
16-Bit Sync Character
SDLC Mode (01111110 Flag)
External Sync Mode
Write Register 2
0
0
1
1
D7 D6 D5 D4 D3 D2 D1 D0
V0
V1
V2
V3
V4
V5
V6
V7
0
1
0
1
X1 Clock Mode
X16 Clock Mode
X32 Clock Mode
X64 Clock Mode
Write Register 5
Interrupt Vector*
D7 D6 D5 D4 D3 D2 D1 D0
Tx CRC Enable
RTS
SDLC/CRC-16
Tx Enable
Send Break
Write Register 3
D7 D6 D5 D4 D3 D2 D1 D0
0
0
1
1
Rx Enable
Sync Character Load Inhibit
Address Search Mode (SDLC)
Rx CRC Enable
Enter Hunt Mode
Auto Enable
0
0
1
1
0
1
0
1
Rx 5 Bits/Character
Rx 7 Bits/Character
Rx 6 Bits/Character
Rx 8 Bits/Character
0
1
0
1
Tx 5 Bits (or less)/Character
Tx 7 Bits/Character
Tx 6 Bits/Character
Tx 8 Bits/Character
DTR
Write Register 6
D7 D6 D5 D4 D3 D2 D1 D0
SYNC7
SYNC1
SYNC7
SYNC3
ADR7
ADR7
SYNC6
SYNC0
SYNC6
SYNC2
ADR6
ADR6
SYNC5
SYNC5
SYNC5
SYNC1
ADR5
ADR5
SYNC4
SYNC4
SYNC4
SYNC0
ADR4
ADR4
SYNC3
SYNC3
SYNC3
1
ADR3
1
SYNC2
SYNC2
SYNC2
1
ADR2
1
SYNC1
SYNC1
SYNC1
1
ADR1
1
SYNC0
SYNC0
SYNC0
1
ADR0
1
Monosync 8 Bits
Monosync 8 Bits
Bisync 16 Bits
Bisync 12 Bits
SDLC
SDLC (Address 0)
10216F-13
Figure 9. Write Register Bit Functions (continued)
Am85C30
21
AMD
Write Register 7
D7 D6 D5 D4 D3 D2 D1 D0
SYNC7
SYNC5
SYNC5
SYNC11
0
SYNC6
SYNC4
SYNC14
SYNC10
1
SYNC5
SYNC3
SYNC13
SYNC9
1
SYNC4
SYNC2
SYNC12
SYNC8
1
SYNC3
SYNC1
SYNC11
SYNC7
1
SYNC2 SYNC1
SYNC0
1
SYNC10 SYNC9
SYNC6 SYNC5
1
1
Monosync 8 Bits
Monosync 8 Bits
Bisync 16 Bits
Bisync 12 Bits
SDLC
SYNC0
1
SYNC8
SYNC4
0
Write Register 7 ′
D7 D6 D5 D4 D3 D2 D1 D0
Auto Tx Flag
Auto EOM Latch Reset
Auto RTS
TxD Pulled High in SDLC NRZI Mode
Fast DTR/REQ Mode
CRC Check Bytes Completely Received
Extended Read Enable
Must Be Set to 0
Write Register 9
Write Register 11
D7 D6 D5 D4 D3 D2 D1 D0
D7 D6 D5 D4 D3 D2 D1 D0
0
0
1
1
0
1
0
1
VIS
NV
DLC
MIE
Status High/Status Low
Interrupt Masking
without INTACK*
0
0
1
1
TRxC Out
TRxC Out
TRxC Out
TRxC Out
0
1
0
1
=
=
=
=
XTAL Output
Transmit Clock
BR Generator Output
DPLL Output
TRxC O/I
No Reset
Channel Reset B
Channel Reset A
Force Hardware Reset
0
0
1
1
*Added Enhancement
0
0
1
1
0
1
0
1
0
1
0
1
Transmit Clock
Transmit Clock
Transmit Clock
Transmit Clock
Receive Clock
Receive Clock
Receive Clock
Receive Clock
=
=
=
=
=
=
=
=
RTxC Pin
TRxC Pin
BR Generator Output
DPLL Output
RTxC Pin
TRxC Pin
BR Generator Output
DPLL Output
RTxC XTAL/No XTAL
10216F-13
Figure 9. Write Register Bit Functions (continued)
22
Am85C30
AMD
Write Register 10
Write Register 12
D7 D6 D5 D4 D3 D2 D1 D0
D7 D6 D5 D4 D3 D2 D1 D0
6-Bit/8-Bit Sync
Loop Mode
Abort/Flag on Underrun
Mark/Flag Idle
Go Active on Roll
0
0
1
1
0
1
0
1
TC0
TC1
TC2
TC3
TC4
TC5
TC6
TC7
NRZ
NRZI
FM1 (Transition = 1)
FM0 (Transition = 0)
Lower Byte of
Time Constant
CRC Preset ‘1’ or ‘0’
Write Register 13
D7 D6 D5 D4 D3 D2 D1 D0
TC8
TC9
TC10
TC11
TC12
TC13
TC14
TC15
Write Register 14
Upper Byte of
Time Constant
D7 D6 D5 D4 D3 D2 D1 D0
BR Generator Enable
BR Generator Source
DTR/Request Function
Auto Echo
Local Loopback
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
Write Register 15
D7 D6 D5 D4 D3 D2 D1 D0
SDLC/HDLC Enhancements Enable*
Zero Count IE
10 × 19 Bit FIFO Enable*
DCD IE
Sync/Hunt IE
CTS IE
Tx Underrun/EOM IE
Break/Abort IE
Null Command
Enter Search Mode
Reset Missing Clock
Disable DPLL
Set Source = BR Generator
Set Source = RTxC
Set FM Mode
Set NRZI Mode
* Added Enhancement
10216F-13
(concluded)
Figure 9. Write Register Bit Functions (continued)
Am85C30 Timing
Read Cycle Timing
The ESCC generates internal control signals from WR
and RD that are related to PCLK. Since PCLK has no
phase relationship with WR and RD, the circuitry generating these internal control signals must provide time for
metastable conditions to disappear. This gives rise to a
recovery time related to PCLK. The recovery time applies only between bus transactions involving the
ESCC. The recovery time required for proper operation
is specified from the falling edge of WR or RD in the first
transaction involving the ESCC, to the falling edge of
WR or RD in the second transaction involving the
ESCC. This time must be at least 3 1/2 PCLK regardless
of which register or channel is being accessed.
Figure 10 illustrates Read cycle timing. Addresses on
A/B and D/C and the status on INTACK must remain stable throughout the cycle. If CE falls after RD falls or if it
rises before RD rises, the effective RD is shortened.
Write Cycle Timing
Figure 11 illustrates Write cycle timing. Addresses on
A/B and D/C and the status on INTACK must remain
stable throughout the cycle. If CE falls after WR falls or if
it rises before WR rises, the effective WR is shortened.
Data must be valid before the rising edge of WR.
Am85C30
23
AMD
Interrupt Acknowledge Cycle Timing
NO TAG illustrates Interrupt Acknowledge cycle timing.
Between the time INTACK goes Low and the falling
edge of RD, the internal and external IEI/IEO daisy
chains settle. If there is an interrupt pending in the ESCC
A/B, D/C
and IEI is High when RD falls, the Acknowledge cycle is
intended for the SCC. In this case, the ESCC may be
programmed to respond to RD Low by placing its interrupt vector on D7–D0 ; it then sets the appropriate Interrupt-Under-Service latch internally.
Address Valid
INTACK
CE
WR
D7 –D0
Data Valid
10216F-14
Figure 10. Read Cycle Timing
A/B, D/C
Address Valid
INTACK
CE
WR
Data Valid
D7 –D0
Figure 11. Write Cycle Timing
10216F-15
INTACK
RD
D7 –D0
Vector
10216F-16
Figure 12. Interrupt Acknowledge Cycle Timing
24
Am85C30
AMD
FIFO
FIFO Enhancements
When used with a DMA controller, the Am85C30 Frame
Status FIFO enhancement maximizes the ESCC’s ability to receive high-speed back-to-back SDLC messages
while minimizing frame overruns due to CPU latencies
in responding to interrupts.
Additional logic was added to the industry-standard
NMOS SCC consisting of a 10-deep by 19-bit status
FIFO, a 14-bit receive byte counter, and control logic as
shown in Figure 13. The 10 × 19 bit status FIFO is separate from the existing 3-byte receive data and error
FIFOs.
When the enhancement is enabled, the status in Read
Register 1 (RR1) and byte count for the SDLC frame will
be stored in the 10 × 19 bit status FIFO. This allows
the DMA controller to transfer the next frame into
SCC Status Reg
(Existing)
RR1
memory while the CPU verifies that the message was
properly received.
Summarizing the operation, data is received, assembled, and loaded into the 3-byte receive FIFO before being transferred to memory by the DMA controller. When
a flag is received at the end of an SDLC frame, the frame
byte count from the 14-bit counter and 5 status bits are
loaded into the status FIFO for verification by the CPU.
The CRC checker is automatically reset in preparation
for the next frame, which can begin immediately. Since
the byte count and status are saved for each frame, the
message integrity can be verified at a later time. Status
information for up to 10 frames can be stored before a
status FIFO overrun could occur.
If receive interrupts are enabled while the 10 × 19 FIFO
is enabled, an SDLC end-of-frame special condition will
Reset on Flag Detect
Increment on Byte DET
Enable Count in SDLC
14-Bit Byte Counter
6 Bits
14 Bits
End-of-Frame Signal
Status Read Comp
Residue Bits(3)
Overrun
CRC Error
10 × 19 Bit FIFO Array
Tail Pointer
4-Bit
Counter
Head Pointer
4-Bit Counter
4-Bit
Comparator
Over Equal
5 Bits
EN
EOF = 1
2 Bits 6-Bit MUX
6 Bits
RR1
6 Bits
Bit 7
Bit 6 Bits 0–5
RR7
8 Bits
FIFO Enable
RR6
Interface to SCC
Byte Counter Contains 14 Bits
for a 16-kb Maximum Count
FIFO Data Available Status Bit
Status Bit Set to 1
When Reading From FIFO
FIFO Overflow Status Bit
MSB of RR(7) is Set on Status FIFO
Overflow
In SDLC mode, the following definitions apply:
• All Sent bypasses MUX and equals contents of SCC Status Register.
• Parity bits bypass MUX and do the same.
• EOF is set to 1 whenever reading from the FIFO.
WR(15) Bit 2 Set
Enables Status FIFO
10216F-17
Figure 13. SCC Status Register Modifications
Am85C30
25
AMD
not lock the 3-byte receive data FIFO. An SDLC
end-of-frame still locks the 3-byte receive data FIFO in
“Interrupt on first Receive Character or Special Condition” and “Interrupt on Special Condition Only” modes
when the 10 × 19 FIFO is disabled. This feature allows
the 10 × 19 SDLC FIFO to accept multiple SDLC frames
without CPU intervention at the end of each frame.
FIFO Detail
For a better understanding of details of the FIFO operation, refer to the block diagram contained in Figure 13.
Enable/Disable
This FIFO is implemented so that it is enabled when
WR15 bit 2 is set and the ESCC is in the SDLC/HDLC
mode, otherwise the status register contents bypass the
FIFO and go directly to the bus interface (the FIFO
pointer logic is reset either when disabled or via a channel or power-on reset). When the FIFO mode is disabled, the ESCC is completely downward-compatible
with the NMOS Am8530. The FIFO mode is disabled on
power-up (WR15 bit 2 is set to 0 on reset). The effects of
backward compatibility on the register set are that RR4
is an image of RR0, RR5 is an image of RR1, RR6 is an
image of RR2, and RR7 is an image of RR3. For the details of the added registers, refer to Figure 15. The status
of the FIFO Enable signal can be obtained by reading
RR15 bit 2. If the FIFO is enabled, the bit will be set to 1;
otherwise, it will be reset.
Read Operation
When WR15 bit 2 is set and the FIFO is not empty, the
next read to status register RR1 or the additional registers RR7 and RR6 will actually be from the FIFO. Reading status register RR1 causes one location of the FIFO
to be emptied, so status should be read after reading the
byte count, otherwise the count will be incorrect. Before
the FIFO underflows, it is disabled. In this case, the multiplexer is switched to allow status to be read directly
Byte Count
0
1
Data Stream
F
A D D D D C C F
Key
F : Flag
A : Address Field
D : Data
C : Control Field
2
3
4
5
6
from the status register, and reads from RR7 and RR6
will contain bits that are undefined. Bit 6 of RR7 (FIFO
Data Available) can be used to determine if status data
is coming from the FIFO or directly from the status register, since it is set to 1 whenever the FIFO is not empty.
Because not all status bits are stored in the FIFO, the All
Sent, Parity, and EOF bits will bypass the FIFO. The
status bits sent through the FIFO will be Residue Bits
(3), Overrun, and CRC Error.
The sequence for proper operation of the byte count and
FIFO logic is to read the registers in the following order,
RR7, RR6, and RR1 (reading RR6 is optional). Additional logic prevents the FIFO from being emptied by
multiple reads from RR1. The read from RR7 latches the
FIFO empty/full status bit (bit 6) and steers the status
multiplexer to read from the SCC megacell instead of
the status FIFO (since the status FIFO is empty). The
read from RR1 allows an entry to be read from the FIFO
(if the FIFO was empty, logic is added to prevent a FIFO
underflow condition).
Write Operation
When the end of an SDLC frame (EOF) has been received and the FIFO is enabled, the contents of the
status and byte-count registers are loaded into the
FIFO. The EOF signal is used to increment the FIFO. If
the FIFO overflows, the MSB of RR7 (FIFO Overflow) is
set to indicate the overflow. This bit and the FIFO control
logic are reset by disabling and reenabling the FIFO
control bit (WR15 bit 2). For details of FIFO control timing during an SDLC frame, refer to Figure 14.
Byte Counter Detail
The 14-bit byte counter allows for packets up to 16K
bytes to be received. For a better understanding of its
operation, refer to Figures 13 and 14.
7
Internal Byte Strobe
Increments Counter
Don’t Load
Reset
Counter On
Byte Counter
1st Flag
Load Counter
Reset Byte
Into FIFO and
Counter Here
Increment PTR
0
1
2
3
F
A D D D D C C F
5
6
7
Internal Byte Strobe
Increments Counter
Reset
Byte Counter
Reset
Byte Counter
Load Counter
Into FIFO and
Increment PTR
10216F-18
Figure 14. SDLC Byte Counting Detail
26
4
Am85C30
AMD
7
RR7
6
FOY FDA
5
4
3
2
BC
13
BC
12
BC
11
BC
10
1
0
BC
9
BC
8
FIFO Data Available Status
1 = Status Reads Will Come From FIFO
0 = Status Reads Will Come From SCC
FIFO Overflow Status
1 = FIFO Overflowed During Operation
0 = Normal
RR6
RR15
7
6
5
4
3
2
1
0
BC
7
BC
6
BC
5
BC
4
BC
3
BC
2
BC
1
BC
0
7
6
5
4
3
2
1
0
•
•
•
•
•
FEN
•
ENH
Read From FIFO
LSB Byte Count
ENH: SDLC/HDLC Enhancement Status
1 = Enhancements Enabled
0 = Enhancements Disabled
Status FIFO Enable Control Bit
1 = Status and Byte Count Will be
Held in the Status FIFO Until Read
0 = Status Will Not be Held (SCC Emulation Mode)
• = No Change From NMOS SCC DFN
10216F-19
Figure 15. SCC Additional Registers
Enable
The byte counter is enabled when the SCC is in the
SDLC/HDLC mode and WR15 bit 2 is set to 1.
Reset
The byte counter is reset whenever an SDLC flag character is received. The reset is timed so that the contents
of the byte counter are successfully written into the
FIFO.
Increment
The byte counter is incremented by writes to the data
FIFO. The counter represents the number of bytes received by the SCC, rather than the number of bytes
transferred from the SCC. (These counts may differ by
up to the number of bytes in the receive data FIFO contained in the SCC.)
Am85C30 SDLC/HDLC Enhancement
Register Access
SDLC/HDLC enhancements on the Am85C30 are enabled or disabled via bits D2 or D0 in WR15. Bit D2 determines whether or not the 10 × 19 bit SDLC/HDLC
frame status FIFO is enabled while bit D0 determines
whether or not other enhancements are enabled via
WR7′. Table 3 shows what functions on the Am85C30
are enabled when these bits are set.
When bit D2 of WR15 is set to 1, two additional registers
(RR6 and RR7) per channel specific to the 10 × 19 bit
Frame Status FIFO are made available. The Am85C30
register map when this function is enabled is shown in
Table 4.
Bit D0 of WR15 determines whether or not other enhancements pertinent only to SDLC/HDLC mode operation are available for programming via WR7′ as shown
below. Write Register 7 prime (WR7′) can be written to
when bit D0 of WR15 is set to 1. When this bit is set, writing to WR7 (flag register) actually writes to WR7′. If bit
D6 of this register is set to 1, previously unreadable registers WR3, WR4, WR5, and WR10 are readable by the
pro-cessor. In addition, WR7′ is also readable by having
this bit set. WR3 is read when a bogus RR9 register is
accessed during a read cycle. WR10 is read by accessing RR11, and WR7′ is accessed by executing a read to
RR14. The Am85C30 register map with bit D0 of WR15
and bit D6 of WR7′ set is shown in Table 5.
If both bits D0 and D2 of WR15 are set to 1 and D6 of
WR7′ is set to 1, then the Am85C30 register map is as
shown in Table 6.
Am85C30
27
AMD
Table 3. Enhancement Options
WR15 Bit D2
10 × 19 Bit
FIFO Enabled
WR15 Bit D0
SDLC/HDLC
Enhancement Enabled
WR7′ Bit D6
Extended
Read Enabled
1
0
x
10 × 19 bit FIFO
enhancement enabled only
0
1
0
SDLC/HDLC enhancements
enabled only
0
1
1
SDLC/HDLC enhancements
enabled with extended read
enabled
1
1
0
10 × 19 bit FIFO and
SDLC/HDLC enhancements
enabled
1
1
1
10 × 19 bit FIFO and
SDLC/HDLC enhancements
with extended read enabled
Functions
Enabled
Table 4. 10 × 19 Bit FIFO Enabled
A/ B
PNT2
PNT1
PNT0
Write
Read
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
WR0B
WR1B
WR2
WR3B
WR4B
WR5B
WR6B
WR7B
WR0A
WR1A
WR2
WR3A
WR4A
WR5A
WR6A
WR7A
RR0B
RR1B
RR2B
RR3B
(RR0B)
(RR1B)
RR6B
RR7B
RR0A
RR1A
RR2A
RR3A
(RR0A)
(RR1A)
RR6A
RR7A
Write
Read
WR8B
WR9
WR10B
WR11B
WR12B
WR13B
WR14B
WR15B
WR8A
WR9
WR10A
WR11A
WR12A
WR13A
WR14A
WR15A
RR8B
RR13B
RR10B
(RR15B)
RR12B
RR13B
(RR10B)
RR15B
RR8A
(RR13A)
RR10A
(RR15A)
RR12A
RR13A
(RR10A)
RR15A
With the Point High command:
28
A/ B
PNT2
PNT1
PNT0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Am85C30
AMD
D7
D6
Must Be Set
to 0
D5
Ext. Read
Enable
D4
D3
DTR/REQ
Fast Mode
Rx comp.
CRC
Force TxD
High
D2
SDLC/HDLC
Auto RTS
Turnoff
D1
D0
SDLC/HDLC
Auto EOM
Reset
SDLC/HDLC
Auto
Tx Flag
WR7′—SDLC/HDLC Programmable Enhancements*
*Note:
Options 3, 4, 5, and 6 may be used regardless of whether SDLC/HDLC mode is selected.
Table 5. SDLC/HDLC Enhancements Enabled
A/ B
PNT2
PNT1
PNT0
Write
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
WR0B
WR1B
WR2
WR3B
WR4B
WR5B
WR6B
WR7B
WR0A
WR1A
WR2
WR3A
WR4A
WR5A
WR6A
WR7A
Write
Read
RR0B
RR1B
RR2B
RR3B
RR4B (WR4B)
RR5B (WR5B)
(RR2B)
(RR3B)
RR0A
RR1A
RR2A
RR3A
RR4A (WR4A)
RR5A (WR5A)
(RR2A)
(RR3A)
With the Point High command:
A/ B
PNT2
PNT1
PNT0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Am85C30
WR8B
WR9
WR10B
WR11B
WR12B
WR13B
WR14B
WR15B
WR8A
WR9
WR10A
WR11A
WR12A
WR13A
WR14A
WR15A
Read
RR8B
RR9 (WR3B)
RR10B
RR11B (WR10B)
RR12B
RR13B
RR14B (WR7′B)
RR15B
RR8A
RR9A (WR3A)
RR10A
RR11A (WR10A)
RR12A
RR13A
RR14A (WR7A)
RR15A
29
AMD
Table 6. SDLC/HDLC Enhancements and 10 × 19 Bit FIFO Enabled
A/ B
PNT2
PNT1
PNT0
Write
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
WR0B
WR1B
WR2
WR3B
WR4B
WR5B
WR6B
WR7B
WR0A
WR1A
WR2
WR3A
WR4A
WR5A
WR6A
WR7A
Write
Read
RR0B
RR1B
RR2B
RR3B
RR4B
RR5B
RR6B
RR7B
RR0A
RR1A
RR2A
RR3A
RR4A
RR5A
RR6A
RR7A
(WR4B)
(WR5B)
(WR4A)
(WR5A)
With the Point High command:
30
A/ B
PNT2
PNT1
PNT0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Am85C30
WR8B
WR9
WR10B
WR11B
WR12B
WR13B
WR14B
WR15B
WR8A
WR9
WR10A
WR11A
WR12A
WR13A
WR14A
WR15A
Read
RR8B
RR9 (WR3B)
RR10B
RR11B (WR10B)
RR12B
RR13B
RR14B (WR7′B)
RR15B
RR8A
RR9A (WR3A)
RR10A
RR11A (WR10A)
RR12A
RR13A
RR14A (WR7′A)
RR15A
AMD
Auto RTS Reset
On the CMOS ESCC, if bit D0 of WR15 and bit D2 of
WR7′ are set to 1 and the channel is in SDLC mode, the
RTS pin may be reset early in the Tx Underrun routine
and the RTS pin will remain active until the last 0 bit of
the closing flag leaves the TxD pin as shown in Figure
16. Note that in order for this to function properly, bits D3
and D2 of WR10 must be set to 1 and 0, respectively.
CRC Character Reception
NMOS Am8530H
On the NMOS Am8530H, when the end-of-frame flag is
detected, the contents of the Receive Shift Register are
transferred to the Receive Data FIFO regardless of the
number of bits accumulated. Because of the 3-bit delay
between the Receive SYNC Register and Receive Shift
Register, the last 2 bits of the CRC check character
received are never transferred to the Receive Data
FIFO. Thus, the received CRC characters are unavailable for use.
CMOS Am85C30
On the Am85C30, the option of being able to receive the
complete CRC characters generated by the transmitter
is provided when both bit D0 of WR15 and bit D5 of WR7′
are set to 1. When these 2 bits are set and an end-offrame flag is detected, the last 2 bits of the CRC will
be clocked into the Receive Shift Register before its
contents are transferred to the Receive Data FIFO. The
data-CRC boundary and CRC character bit formats for
each Residue Code provided are shown in Figures 17A
through 17D for each character length selected.
Data Being Sent
Data
CRC
CRC
Flag
Tx Underrun/EOM
RTS Bit D1 WR5
RTS Pin (Active Low)
10216F-20
Figure 16. Auto RTS Reset Mode
Am85C30
31
AMD
Residue
Code
012
001
D
C0
C5
C8
D
C1
C6
C9
D
C2
C7
C10
D
C3
C8
C11
D
C4
C9
C12
Residue
Code
012
101
C0
C5
C10
C13
C1
C6
C11
C14
C2
C7
C12
C15
D
D
C4
C8
D
C0
C5
C9
Residue
Code
012
100
D
D
C3
C8
D
D
C4
C9
D
C0
C5
C10
D
C1
C6
C11
D
C2
C7
C12
D
C1
C6
C10
D
C2
C7
C11
D
C3
C8
C12
D
C4
C9
C13
C0
C5
C10
C14
C1
C6
C11
C15
D
C2
C7
C12
C13
D
C3
C8
C13
C14
D
C4
C9
C14
C15
Residue
Code
012
010
D
C3
C8
C13
D
C4
C9
C14
C0
C5
C10
C15
D
D
C2
C7
C8
D
D
C3
C8
C9
D
C2
C7
C12
C14
D
C3
C8
C13
C15
D
D
C4
C9
C10
D
C0
C5
C10
C11
D
C1
C6
C11
C12
Residue
Code
012
110
D
D
C1
C6
C8
D
D
C2
C7
C9
D
D
C3
C8
C10
D
D
C4
C9
C11
D
C0
C5
C10
C12
D
C1
C6
C11
C13
10216F-21
Figure 17A. 5 Bits/Character
32
Am85C30
AMD
Residue
Code
012
010
D
C0
C6
C8
D
C1
C7
C9
D
C2
C8
C10
D
C3
C9
C11
D
C4
C10
C12
Residue
Code
012
110
D
C5
C11
C13
C0
C6
C12
C14
C1
C7
C13
C15
D
D
C5
C8
D
C0
C6
C9
Residue
Code
012
001
D
D
C4
C8
D
D
C5
C9
D
C0
C6
C10
D
C1
C7
C11
D
C2
C8
C12
D
D
C3
C9
D
D
C4
C10
D
D
C5
C11
D
C0
C6
C12
D
C2
C8
C11
D
C3
C9
C12
D
C4
C10
C13
D
C5
C11
C14
C0
C6
C12
C15
D
C2
C8
C13
D
C3
C9
C14
D
C4
C10
C15
D
C0
C6
C12
C13
D
C1
C7
C13
C14
D
C2
C8
C14
C15
Residue
Code
012
101
D
C3
C9
C13
D
C4
C10
C14
D
C5
C11
C15
D
D
C3
C8
D
D
C4
C9
Residue
Code
012
011
D
D
C2
C8
D
C1
C7
C10
D
D
C5
C10
D
C0
C6
C11
D
C1
C7
C12
Residue
Code
012
100
D
C1
C7
C13
D
C2
C8
C14
D
C3
C9
C15
D
D
C1
C7
C8
D
D
C2
C8
C9
D
D
C3
C9
C10
D
D
C4
C10
C11
D
D
C5
C11
C12
10216F-21
Figure 17B. 6 Bits/Character
Am85C30
33
AMD
Residue
Code
012
111
D
C0
C7
C8
D
C1
C8
C9
D
C2
C9
C10
D
C3
C10
C11
D
C4
C11
C12
Residue
Code
012
100
D
C5
C12
C13
D
C6
C13
C14
C0
C7
C14
C15
D
D
C6
C8
D
C0
C7
C9
Residue
Code
012
010
D
D
C5
C8
D
D
C6
C9
D
C0
C7
C10
D
C1
C8
C11
D
C2
C9
C12
D
D
C4
C9
D
D
C5
C10
D
D
C6
C11
D
C0
C7
C12
D
C2
C9
C11
D
C3
C10
C12
D
C4
C11
C13
D
C5
C12
C14
D
C6
C13
C15
D
C2
C9
C13
D
C3
C10
C14
D
C4
C11
C15
D
C0
C7
C13
D
C1
C8
C14
D
C2
C9
C15
Residue
Code
012
110
D
C3
C10
C13
D
C4
C11
C14
D
C5
C12
C15
D
D
C4
C8
D
D
C5
C9
Residue
Code
012
001
D
D
C3
C8
D
C1
C8
C10
D
D
C6
C10
D
C0
C7
C11
D
C1
C8
C12
Residue
Code
012
101
D
C1
C8
C13
D
C2
C9
C14
D
C3
C10
C15
D
D
C2
C8
D
D
C3
C9
D
D
C4
C10
D
D
C5
C11
D
D
C6
C12
Residue
Code
012
011
D
D
C1
C8
D
D
C2
C9
D
D
C3
C10
D
D
C4
C11
D
D
C5
C12
D
D
C6
C13
D
C0
C7
C14
D
C1
C8
C15
10216F-21
Figure 17C. 7 Bits/Character
34
Am85C30
AMD
Residue
Code
012
011
(No Residue)
Residue
Code
012
111
(1 Residue Bit)
D D D D D D D D
C0 C1 C2 C3 C4 C5 C6 C7
C8 C9 C10 C11 C12 C13 C14 C15
D
D
C7
C8
D
C0
C8
C9
Residue
Code
012
000
(2 Residue Bits)
D
D
C6
C8
D
D
C7
C9
D
C0
C8
C10
D
C1
C9
C11
D
C2
C10
C12
D
C3
C11
C13
D
D
C5
C9
D
D
C6
C10
D
D
C7
C11
D
C0
C8
C12
D
C1
C9
C13
D
C4
C12
C14
D
C5
C13
C15
D
D
C5
C8
D
D
C6
C9
D
D
C3
C9
D
D
C4
C10
D
D
C5
C11
D
D
C6
C12
D
D
C7
C13
D
C3
C11
C12
D
C4
C12
C13
D
C5
C13
C14
D
C6
C14
C15
D
D
C7
C10
D
C0
C8
C11
D
C1
C9
C12
D
C2
C10
C13
D
C3
C11
C14
D
C4
C12
C15
D
C1
C9
C14
D
C2
C10
C15
D
D
C7
C14
D
C0
C8
C15
Residue
Code
012
110
(5 Residue Bits)
D
C2
C10
C14
D
C3
C11
C15
D
D
C3
C8
D
D
C4
C9
Residue
Code
012
001
(6 Residue Bits)
D
D
C2
C8
D
C2
C10
C11
Residue
Code
012
100
(3 Residue Bits)
Residue
Code
012
010
(4 Residue Bits)
D
D
C4
C8
D
C1
C9
C10
D
D
C5
C10
D
D
C6
C11
D
D
C7
C12
D
C0
C8
C13
Residue
Code
012
101
(7 Residue Bits)
D
C0
C8
C14
D
C1
C9
C15
D
D
C1
C8
D
D
C2
C9
D
D
C3
C10
D
D
C4
C11
D
D
C5
C12
D
D
C6
C13
10216F-21
(concluded)
Figure 17D. 8 Bits/Character
Am85C30
35
AMD
Auto Flag Mode
WR5 (D0) and the Tx Underrun/EOM bit in RR0 (D6).
However, if the Transmit Enable bit is set to 0 when a
transmit underrun (i.e., both the Transmit Buffer and
Transmit Shift Register become empty) occurs, the
CRC check characters will not be sent regardless of the
state of the Tx Underrun/EOM bit.
On the NMOS Am8530H, if the transmitter is actively
mark idling and a frame of data is ready to be transmitted, the Mark/Flag Idle bit must be set to 0 before data is
written to WR8, otherwise the opening flag will not be
sent properly. However, care must be exercised in doing
this because the mark idle pattern (eight 1 bits) is transmitted 8 bits at a time, and all 8 bits must have transferred out of the Transmit Shift Register before a flag
may be loaded and sent. If data is written into the Transmit Buffer (WR8) before the flag is loaded into the Transmit Shift Register, the data character written to WR8 will
supersede flag transmission and the opening flag will
not be transmitted.
If the Transmit Enable bit is set to 1 when an underrun
occurs, then the state of the Tx Underrun/EOM bit and
the Abort/Flag on Underrun bit in WR10 (D2) determine
the action taken by the transmitter. The Abort/Flag on
Underrun bit may be set or reset by the processor,
whereas the Tx Underrun/EOM bit is set by the transmitter and can only be reset by the processor via the Reset
Tx Underrun/EOM Command in WR0.
On the CMOS Am85C30, if bit D0 of WR15 is set to 1 and
the ESCC is programmed for SDLC operation, an option
is provided via bit D0 of WR7′ that eliminates this requirement. If bit D0 of WR7′ is set to 1 and a character is
written to the Transmit Buffer while the transmitter is
mark idling, the Mark/Flag Idle bit in WR10 need not be
reset to 0 in order to have the opening flag sent because
the transmitter will automatically send it before commencing to send data.
If the Tx Underrun/EOM bit is set to 1 when an underrun
occurs, the transmitter will close the frame by sending a
flag; however, if this bit is set to 0, the frame data will be
appended with either the accumulated CRC characters
followed by a flag or an abort pattern followed by a flag,
depending on the state of the Abort/Flag on Underrun bit
in the WR10 (D2). In either case, after the closing flag is
sent, the transmitter will idle the transmission line as
specified by the Mark/Flag Idle bit D3 in WR10.
In addition, as long as bit D0 of WR15 and bit D1 of WR7′
are set to 1, the CRC transmit generator will be automatically preset to the initial state programmed by bit D7
of WR10 (so the Reset Tx CRC Generator command is
also not necessary), and the Tx Underrun/EOM latch
will be reset automatically on every new frame sent. This
ensures that an opening flag and proper CRC generation and transmission will always be sent without processor intervention under varying bus latency conditions.
Hence, if the CRC check characters are to be properly
appended to a frame, the Abort/Flag on Underrun bit
must be set to 0, and the Reset Tx Underrun/EOM Command must be issued after the first but before the last
character is written to the Transmit Buffer. This will ensure that either an abort or the CRC will be transmitted if
an underrun occurs. Normally, the Abort/Flag on Underrun bit in WR10 should be set to 1 around the same time
that the Tx Underrun/EOM bit is reset so that an abort
will be sent if the transmitter accidentally underruns, and
then set to 0 near the end of the frame to allow the correct transmission of CRC.
Auto Transmit CRC Generator Preset
The NMOS Am8530H does not automatically preset the
CRC generator prior to frame transmission. This must
be done in software, usually during the initialization routine. This is accomplished by issuing the Reset Tx CRC
Generator Command via WR0. For proper results, this
command must be issued while the transmitter is enabled and idling and before any data are written to the
Transmit Buffer.
In addition, if CRC is to be used, the transmit CRC generator must be enabled by setting bit D0 of WR5 to 1.
CRC is normally calculated on all characters between
opening and closing flags, so this bit should be set to 1 at
initialization and never changed.
On the CMOS Am85C30, setting bit D0 of WR15 to 1 will
cause the transmit CRC generator to be preset automatically every time an opening flag is sent, so the Reset Tx CRC Generator Command is not necessary.
Auto Tx Underrun/EOM Latch Reset
On the ESCC, the transmission of the CRC check characters is controlled by the Transmit CRC Enable bit in
36
On the Am85C30, if bit D0 of WR15 is set to 1, the option
of having the Tx Underrun/EOM bit reset automatically
at the start of every frame is provided via bit D1 of WR7′.
This helps alleviate the software burden of having to respond within one character time when high-speed data
are being sent.
SDLC/HDLC NRZI Transmitter Disabling
On the NMOS Am8530H, if NRZI encoding is being
used and the transmitter is disabled, the state of the TxD
pin will depend on the last bit sent. That is, the TxD pin
may either idle in a Low or High state as shown in
Figure 18.
On the CMOS Am85C30, an option is provided that allows setting the TxD pin High when operating in SDLC
mode with NRZI encoding enabled. If bit D0 of WR15 is
set to 1, then bit D3 of WR7′ can be used to set the TxD
pin High. Note that the operation of this bit is independent of the Tx Enable bit in WR5. The Tx Enable bit in
WR5 is used to disable and enable the transmitter,
Am85C30
AMD
1
1
0
0
1
1
1
1
1
1
0
0
Transmitter Disabled Here
TxD Pin Output (NRZI Encoded)
Hi
Lo
10216F-22
Figure 18. Transmitter Disabling with NRZI Encoding
whereas bit D3 of WR7′ acts as a pseudo transmitter disable and enable by just forcing the TxD pin High when
set even though the transmitter may actually be mark or
flag idling. Care must be used when setting this bit because any character being transmitted at the time this bit
is set will be “chopped off,” and data written to the Transmit Buffer while this bit is set will be lost.
When the transmit underrun occurs and the CRC and
closing flag have been sent, bit D3 can be set to pull TxD
High. When ready to start sending data again this bit
must be reset to 0 before the first character is written to
the Transmit Buffer. Note that resetting this bit causes
the TxD pin to take whatever state the NRZI encoder is
in at the time, so synchronization at the receiver may
take longer because the first transition seen on the TxD
pin may not coincide with a bit boundary. Note that in order for this to function properly, bits D3 and D2 of WR10
must be set to 1 and 0, respectively.
Interrupt Masking Without INTACK
The NMOS Am8530H’s ability to mask lower priority interrupts is done via the IUS bit. This bit is internal to the
SCC and is not observable by the processor. Being able
to automatically mask lower priority interrupts allows a
modular approach to coding interrupt routines. However, using the masking capabilities of the NMOS SCC
requires that the INTACK cycle be generated. In standalone applications, having to generate INTACK through
external hardware in order to use this capability is an
unnecessary expense.
On the CMOS Am85C30, if bit D5 in WR9 is set to 1, the
INTACK cycle does not need to be generated in order to
have the IUS bit set. This allows the user to respond to
ESCC interrupt requests with a software acknowledgment through RR2. When bit D5 in WR9 is set and an
interrupt occurs, a read to RR2 emulates a hardware
Interrupt Acknowledge cycle as it functions in Vectored
mode. In this case the CPU must first read RR2 to determine the internal interrupt source and then jump to the
appropriate interrupt routine. Reading RR2 sets the IUS
bit for the highest priority IP. After the interrupting condition is cleared, the routine can then read RR3 to determine if any other IPs are set and clear them. At the end
of the interrupt routine, a Reset IUS command must be
issued to unlock the internal daisy chain.
Since the CPU can acknowledge the ESCC of highest
priority with a read of its RR2 interrupt vector, there is no
need for an external daisy chain. IEI for all ESCC devices should be tied active High. When acknowledging
an ESCC interrupt request, the CPU must issue one
read to RR2 per interrupt request. The modified interrupt vector can be read from Channel B, or the original
vector stored in WR2 can be read from Channel A.
Either action will produce the same internal actions on
the IUS logic. Note that the No Vector and Vector Includes Status bits in WR9 are ignored when bit D5 in
WR9 is set to 1.
2-Mb/s FM Data Transmission and
Reception
The 16-MHz version of the CMOS Am85C30
(Am85C30-16) is capable of transmitting and receiving
FM-encoded data at the rate of 2 Mb/s. This is accomplished by applying a 32-MHz clock to the RTxC pin and
assigning this waveform to drive the Internal Digital
Phase-Locked Loop (DPLL) clock. This feature allows
the user to send both clock and data information over
the same line at 2 Mb/s and can eliminate external
DPLLs required for high-speed NRZ data clock
generation.
Am85C30
37
AMD
ABSOLUTE MAXIMUM RATINGS
OPERATING RANGES
Storage Temperature . . . . . . . . . . . –65°C to +150°C
Voltage at any Pin
Relative to VSS . . . . . . . . . . . . . . . . . –0.5 to +7.0 V
Commercial (C) Devices
Ambient Temperature (TA) . . . . . . . 0°C to +70°C
Supply Voltage (VCC) . . . . . . . . . . . . . +5 V ± 10%
Industrial (I) Devices
Ambient Temperature (TA) . . . . . –40°C to +85°C
Supply Voltage (VCC) . . . . . . . . . . . . . . 5 V ±10%
Military (M) Devices
Case Temperature (TC) . . . . . . . –55°C to 125°C
Supply Voltage (VCC) . . . . . . . . . . . . . . 5 V ±10%
Stresses above those listed under ABSOLUTE MAXIMUM
RATINGS may cause permanent device failure. Functionality
at or above these limits is not implied. Exposure to absolute
maximum ratings for extended periods may affect device
reliability.
Operating ranges define those limits between which the functionality of the device is guaranteed.
DC CHARACTERISTICS over COMMERCIAL operating range
Parameter
Symbol
Parameter
Description
Test Conditions
Min
Max
Unit
VIH
Input High Voltage
Commercial
2.2
VCC +0.3*
V
VIL
Input Low Voltage
–0.3*
0.8
V
VOH1
Output High Voltage
IOH = –1.6 mA
2.4
V
VOH2
Output High Voltage
IOH = –250 µA
VCC –0.8
V
VOL
Output Low Voltage
IOL = +2.0 mA
IIL
Input Leakage
IOL
ICC1
CIN
0.4
V
0.4 V ≤ VIN ≤ 2.4 V
±10.0
µA
Output Leakage
0.4 V ≤ VOUT ≤ 2.4 V
±10.0
µA
VCC Supply Current
8.192 MHz
10 MHz
12 MHz
16.384 MHz
18
18
22
22
mA
mA
mA
mA
10
pF
15
pF
20
pF
Inputs at
voltage rails,
output unloaded
Input Capacitance
COUT
Output Capacitance
CMO
Bidirectional Capacitance
Unmeasured pins returned
to ground = 1 MHz over
specified temperature range
*VIH Max and VIL Min not tested. Guaranteed by design.
Standard Test Conditions
The characteristics below apply for the following standard test conditions, unless otherwise noted. All
voltages are referenced to GND. Positive current flows
into the referenced pin. Standard conditions are as
follows:
+4.5 V ≤ VCC ≤ +5.5 V
GND = 0 V
0°C ≤ TA ≤ 70°C
SWITCHING TEST CIRCUITS
Standard Test Dynamic Load Circuit
Open-Drain Test Load
+5 V
IO L = 2 mA
Threshold
Voltage
VT = 1.4 V
2.2 K
From Output
Under Test
75 pF
From Output
Under Test
75 pF
IOH = 250 µA
10216F-23
38
10216F-24
Am85C30
AMD
SWITCHING CHARACTERISTICS over COMMERCIAL operating range
General Timing (see Figure 19)
No.
Parameter
Symbol
8.192 MHz
Parameter
Description
Min
Max
10 MHz
Min
Max
16.384 MHz
Min
Max
Unit
1
TdPC(REQ)
PCLK ↓ to W/REQ Valid Delay
250
150
80
ns
2
TdPC(W)
PCLK ↓ to Wait Inactive Delay
350
250
180
ns
3
TsRXC(PC)
RxC ↑ to PCLK ↑ Setup Time
(Notes 1, 4 & 8)
4
TsRXD(RXCr)
RxD to RxC ↑ Setup Time
(Xl Mode) (Note 1)
0
0
0
ns
5
ThRXD(RXCr)
RxD to RxC ↑ Hold Time
(Xl Mode) (Note 1)
150
125
50
ns
6
TsRXD(RXCf)
RxD to RxC ↓ Setup Time
(Xl Mode) (Notes 1, 5)
0
0
0
ns
7
ThRXD(RXCf)
RxD to RxC ↓ Hold Time
(Xl Mode) (Notes 1, 5)
150
125
50
ns
8
TsSY(RXC)
SYNC to RxC ↑ Setup Time
(Note 1)
–200
–150
–100
ns
9
ThSY(RXC)
SYNC to RxC ↑ Hold Time
(Note 1)
5TcPC
5TcPC
5TcPc
ns
10
TsTXC(PC)
TxC ↓ to PCLK ↑ Setup Time
(Notes 2, 4 & 8)
NA
NA
NA
11
TdTXCf(TXD)
TxC ↓ to TxD Delay (Xl Mode)
(Note 2)
200
150
80
ns
12
TdTXCr(TXD)
TxC ↑ to TxD Delay (Xl Mode)
(Notes 2, 5)
200
150
80
ns
13
TdTXD(TRX)
TxD to TRxC Delay
(Send Clock Echo)
200
140
80
ns
14a
TwRTXh
RTxC High Width (Note 6)
150
120
80
ns
14b
TwRTxh(E)
RTxC High Width (Note 9)
50
40
15.6
ns
15a
TwRTXI
RTxC Low Width (Note 6)
150
120
80
ns
15b
TwRTXl(E)
RTxC Low Width (Note 9)
50
40
15.6
ns
16a
TcRTX
RTxC Cycle Time (Notes 6, 7)
488
400
244
ns
16b
TcRTx(E)
RTxC Cycle Time (Note 9)
125
17
TcRTXX
Crystal Oscillator Period (Note 3)
125
18
TwTRXh
TRxC High Width (Note 6)
150
120
80
ns
19
TwTRXI
TRxC Low Width (Note 6)
150
120
80
ns
20
TcTRX
TRxC Cycle Time (Notes 6, 7)
488
400
244
ns
21
TwEXT
DCD or CTS Pulse Width
200
120
70
ns
22
TwSY
SYNC Pulse Width
200
120
70
ns
NA
NA
NA
NA
100
1000
100
NA
NA
31.25
1000
62
ns
1000
ns
Notes:
1. RxC is RTxC or TRxC, whichever is supplying the receive clock.
2. TxC is TRxC or RTxC, whichever is supplying the transmit clock.
3. Both RTxC and SYNC have 30-pF capacitors to ground connected to them.
4. Parameter applies only if the data rate is one-fourth the PCLK rate. In all other cases, no phase relationship between
RxC and PCLK or TxC and PCLK is required.
5. Parameter applies only to FM encoding/decoding.
6. Parameter applies only for transmitter and receiver; DPLL and baud rate generator timing requirements are identical to
chip PCLK requirements.
7. The maximum receive or transmit data is 1/4 PCLK.
8. External PCLK to RxC or TxC synchronization requirement eliminated for PCLK divide-by-four operation.
TRxC and RTxC rise and fall times are identical to PCLK. Reference timing specs Tfpc and Trpc.
Tx and Rx input clock slow rates should be kept to a maximum of 30 ns. All parameters related to input CLK edges
should be referenced at the point at which the transition begins or ends, whichever is the worst case.
9. ENHANCED FEATURE—RTxC used as input to internal DPLL only.
Am85C30
39
AMD
SWITCHING TEST INPUT/OUTPUT WAVEFORM
2.4 V
2.0 V
0.8 V
0.4 V
2.0 V
Test
Points
0.8 V
10216F-25
AC testing: Inputs are driven at 2.4 V for a logic 1 and 0.4 V for a logic 0.
Timing measurements are made at 2.0 V for a logic 1 and 0.8 V for logic 0.
PCLK
1
W/REQ
Request
2
W/REQ
Wait
3
RTxC, TRxC
Receive
4
5
6
7
RxD
8
9
SYNC
External
10
TRxC RTxC
Transmit
12
11
TxD
13
TRxC
Output
14
15
RTxC
16
17
TRxC
18
19
20
CTS, DCD, R1
21
21
22
22
SYNC
Input
10216F-26
Figure 19. General Timing
40
Am85C30
AMD
SWITCHING CHARACTERISTICS over COMMERCIAL operating range (continued)
System Timing (see Figure 20)
No.
Parameter
Symbol
Parameter
Description
10 MHz
8.192 MHz
Min
Max
Min
Max
Unit
1
TdRXC(REQ)
RXC ↑ W/REQ Valid Delay
(Note 2)
8
12
8
12
TcPc
2
TdRXC(W)
RXC ↑ to Wait Inactive Delay
(Notes 1, 2)
8
14
8
14
TcPc
3
TdRXC(SY)
RxC ↑ to SYNC Valid Delay
(Note 2)
4
7
4
7
TcPc
4
TdRXC(INT)
RxC ↑ to INT Valid Delay
(Notes 1, 2)
10
16
10
16
TcPc
5
TdTXC(REQ)
TxC ↓ to W/REQ Valid Delay
(Note 3)
5
8
5
8
TcPc
6
TdTXC(W)
TxC ↓ to Wait Inactive Delay
(Notes 1, 3)
5
11
5
11
TcPc
7a
TdTXC(DRQ)
TxC ↓ to DTR/REQ Valid Delay
(Note 3)
4
7
4
7
TcPc
7b
TdTXC(EDRQ)
TxC ↓ to DTR/REQ Valid Delay
(Notes 3, 4)
5
8
5
8
TcPc
8
TdTXC(INT)
TxC ↓ to INT Valid Delay
(Notes 1, 3)
6
10
6
10
TcPc
9
TdSY(INT)
SYNC Transition to INT Valid
Delay (Note 1)
2
6
2
6
TcPc
10
TdEXT(INT)
DCD or CTS Transition to INT
Valid Delay (Note 1)
2
6
2
6
TcPc
Min
Max
Unit
No.
Parameter
Symbol
Parameter
Description
16.384 MHz
1
TdRXC(REQ)
RXC ↑ W/REQ Valid Delay
(Note 2)
8
12
TcPc
2
TdRXC(W)
RXC ↑ to Wait Inactive Delay
(Notes 1, 2)
8
14
TcPc
3
TdRXC(SY)
RxC ↑ to SYNC Valid Delay
(Note 2)
4
7
TcPc
4
TdRXC(INT)
RxC ↑ to INT Valid Delay
(Notes 1, 2)
10
16
TcPc
5
TdTXC(REQ)
TxC ↓ to W/REQ Valid Delay
(Note 3)
5
8
TcPc
6
TdTXC(W)
TxC ↓ to Wait Inactive Delay
(Notes 1, 3)
5
11
TcPc
7a
TdTXC(DRQ)
TxC ↓ to DTR/REQ Valid Delay
(Note 3)
4
7
TcPc
7b
TdTXC(EDRQ)
TxC ↓ to DTR/REQ Valid Delay
(Notes 3, 4)
5
8
TcPc
8
TdTXC(INT)
TxC ↓ to INT Valid Delay
(Notes 1, 3)
6
10
TcPc
9
TdSY(INT)
SYNC Transition to INT Valid
Delay (Note 1)
2
6
TcPc
10
TdEXT(INT)
DCD or CTS Transition to INT
Valid Delay (Note 1)
2
6
TcPc
Notes:
1. Open-drain output, measured with open-drain test load.
2. RxC is RTxC or TRxC, whichever is supplying the receive clock.
3. TxC is TRxC or RTxC, whichever is supplying the transmit clock.
4. Parameter applies to Enhanced Request mode only.
Am85C30
41
AMD
SWITCHING CHARACTERISTICS over COMMERCIAL operating range (continued)
Read and Write Timing (see Figure 21)
No.
Parameter
Symbol
8.192 MHz
Parameter
Description
10 MHz
16.384 MHz
Min
Max
Min
Max
Min
Max
Unit
1
TwPCI
PCLK Low Width
50
2000
40
2000
26
2000
ns
2
TwPCh
PCLK High Width
50
2000
40
2000
26
2000
ns
3
TfPC
PCLK Fall Time
8
ns
4
TrPC
PCLK Rise Time
8
ns
5
TcPC
PCLK Cycle Time
122
6
TsA(WR)
Address to WR ↓ Setup Time
70
7
ThA(WR)
Address to WR ↑ Hold Time
0
0
0
ns
8
TsA(RD)
Address to RD ↓ Setup Time
70
50
35
ns
15
12
15
4000
12
100
4000
50
61
4000
35
9
ThA(RD)
Address to RD ↑ Hold Time
0
0
0
ns
10
TsIA(PC)
INTACK to PCLK ↑ Setup Time
20
20
15
ns
11
TsIA(WR)
INTACK to WR ↓ Setup Time
(Note 1)
145
120
70
ns
12
ThIA(WR)
INTACK to WR ↑ Hold Time
0
0
0
ns
13
TsIA(RD)
INTACK to RD ↓ Setup Time
(Note 1)
145
120
70
ns
14
ThIAi(RD)
INTACK to RD ↑ Hold Time
0
0
0
ns
15
ThIA(PC)
INTACK to PCLK ↑ Hold Time
40
30
15
ns
16
TsCEI(WR)
CE Low to WR ↓ Setup Time
0
0
0
ns
17
ThCE(WR)
CE to WR ↑ Hold Time
0
0
0
ns
18
TsCEh(WR)
CE High to WR ↓ Setup Time
60
50
30
ns
19
TsCEI(RD)
CE Low to RD ↓ Setup Time
(Note 1)
0
0
0
ns
20
ThCE(RD)
CE to RD ↑ Hold Time (Note1)
0
0
0
ns
21
TsCEh(RD)
CE High to RD ↓ Setup Time
(Note 1)
60
50
30
ns
22
TwRDI
RD Low Width (Note 1)
150
125
75
ns
23
TdRD(DRA)
RD ↓ to Read Data Active Delay
0
0
0
ns
24
TdRDr(DR)
RD ↑ to Read Data Not Valid Delay
0
0
0
ns
25
TdRDf(DR)
RD ↓ to Read Data Valid Delay
140
120
70
ns
26
TdRD(DRz)
RD ↑ to Read Data Float Delay
(Note 2)
40
35
20
ns
Notes:
1. Parameter does not apply to Interrupt Acknowledge transactions.
2. Float delay is defined as the time at which the data bus is released from its drive state with a maximum DC load and
minimum AC load.
42
ns
ns
Am85C30
AMD
RTxC TRxC
Receive
W/REQ
Request
1
W/REQ
Wait
2
SYNC
Output
3
INT
4
RTxC
TRxC
Transmit
W/REQ
Request
5
W/REQ
Wait
6
DTR REQ
Request
7
INT
8
CTS, DCD, RI
SYNC
Input
9
INT
10
10216F-27
Figure 20. System Timing
Am85C30
43
AMD
1
PCLK
2
3
5
6
4
A/B, D/C
7
10
8
9
INTACK
11
10
12
13
14
15
CE
16
18
RD
21
19
22
20
D7 –D0
Read
Valid
17
23
24
25
27
26
WR
28
D7 –D0
Write
Valid
29
31
30
W/REQ
Wait
32
W/REQ
Request
35
33
DTR/REQ
Request
34
36
INT
37
10216F-28
Figure 21. Read and Write Timing
44
Am85C30
AMD
SWITCHING CHARACTERISTICS over COMMERCIAL operating range (continued)
Interrupt Acknowledge Timing, Reset Timing, Cycle Timing (see Figures 22–24)
No.
Parameter
Symbol
8.192 MHz
Parameter
Description
Min
Max
10 MHz
Min
220
Max
16.384 MHz
Min
Unit
100
ns
20
ns
27
TdA(DR)
Address Required Valid to Read
Data Valid Delay
28
TwWRI
WR Low Width
29
TdWRf(DW)
WR ↓ to Write Data Valid
30
ThDW(WR)
Write Data to WR ↑ Hold Time
31
TdWR(W)
WR ↓ to Wait Valid Delay (Note 2)
170
100
50
ns
150
160
Max
125
35
0
75
35
0
ns
0
ns
32
TdRD(W)
RD ↓ to Wait Valid Delay (Note 2)
170
100
50
ns
33
TdWRf(REQ)
WR ↓ to W/REQ Not Valid Delay
170
120
70
ns
70
ns
34
TdRDf(REQ)
RD ↓ to W/REQ Not Valid Delay
170
120
35a
TdWRr(REQ)
WR ↓ to DTR/REQ Not Valid Delay
4.0TcPc
4.0TcPc
35b
TdWRr(EREQ)
WR ↓ to DTR/REQ Not Valid Delay
120
120
36
TdRDr(REQ)
RD ↑ to DTR/REQ Not Valid Delay
NA
37
TdPC(INT)
PCLK ↓ to INT Valid Delay (Note 2)
500
38
TdIAi(RD)
INTACK to RD ↓ (Acknowledge)
Delay (Note 3)
150
39
TwRDA
RD (Acknowledge) Width
150
40
TdRDA(DR)
RD ↓ (Acknowledge) to Read
Data Valid Delay
41
TsIEI(RDA)
IEI to RD ↓ (Acknowledge) Setup
Time
95
80
50
ns
42
ThIEI(RDA)
IEI to RD ↑ (Acknowledge) Hold
Time
0
0
0
ns
43
TdIEI(IEO)
IEI to IEO Delay Time
95
80
45
ns
44
TdPC(IEO)
PCLK ↑ to IEO Delay
200
175
80
ns
45
TdRDA(INT)
RD ↓ to INT Inactive Delay (Note 2)
200
ns
46
TdRD(WRQ)
RD ↑ to WR ↓ Delay for No Reset
47
TdWRQ(RD)
WR ↑ to RD ↓ Delay for No Reset
15
48
TwRES
WR and RD Coincident Low for
Reset
150
49
Trc
Valid Access Recovery Time
(Note 1)
3.5
3.5
ns
NA
NA
ns
400
175
ns
50
125
ns
70
320
15
ns
75
120
450
15
70
125
140
4.0TcPc ns
ns
10
ns
15
10
ns
100
75
ns
3.5
TcPc
Notes:
1. Parameter applies only between transactions involving the ESCC, if WR/RD falling edge is synchronized to PCLK
falling edge, then TrC = 3TcPc.
2. Open-drain output, measured with open-drain test load.
3. Parameter is system dependent. For any SCC in the daisy chain, TdIAi(RD) must be greater than the sum of DdPC(IEO)
for the highest priority device in the daisy chain, TsIEI(RDA) for the SCC, and TdIEI(IEO) for each device separating
them in the daisy chain.
4. Parameter applies to Enhanced Request mode only.
Am85C30
45
AMD
WR
46
48
47
RD
10216F-29
Figure 22. Reset Timing
CE
49
RD or WR
10216F-30
Figure 23. Cycle Timing
PCLK
10
15
INTACK
14
10
38
RD
39
23
24
D7 –D0
Valid
40
26
42
41
IEI
43
44
IEO
45
INT
10216F-31
Figure 24. Interrupt Acknowledge Timing
46
Am85C30
AMD
SWITCHING CHARACTERISTICS over MILITARY/INDUSTRIAL operating range
General Timing (see Figure 19)
No.
Parameter
Symbol
8.192 MHz
Parameter
Description
Min
Max
10 MHz
Min
Max
16.384 MHz
Min
Max
Unit
1
TdPC(REQ)
PCLK ↓ to W/REQ Valid Delay
250
150
80
ns
2
TdPC(W)
PCLK ↓ to Wait Inactive Delay
350
250
180
ns
3
TsRXC(PC)
RxC ↑ to PCLK ↑ Setup Time
(Notes 1, 4 & 8)
4
TsRXD(RXCr)
RxD to RxC ↑ Setup Time
(Xl Mode) (Note 1)
0
0
0
ns
5
ThRXD(RXCr)
RxD to RxC ↑ Hold Time
(Xl Mode) (Note 1)
150
125
50
ns
6
TsRXD(RXCf)
RxD to RxC ↓ Setup Time
(Xl Mode) (Notes 1, 5)
0
0
0
ns
7
ThRXD(RXCf)
RxD to RxC ↓ Hold Time
(Xl Mode) (Notes 1, 5)
150
125
50
ns
8
TsSY(RXC)
SYNC to RxC ↑ Setup Time
(Note 1)
–200
–150
–100
ns
9
ThSY(RXC)
SYNC to RxC ↑ Hold Time
(Note 1)
5TcPC
5TcPC
5TcPc
ns
10
TsTXC(PC)
TxC ↓ to PCLK ↑ Setup Time
(Notes 2, 4 & 8)
NA
NA
NA
11
TdTXCf(TXD)
TxC ↓ to TxD Delay (Xl Mode)
(Note 2)
200
150
80
ns
12
TdTXCr(TXD)
TxC ↑ to TxD Delay (Xl Mode)
(Notes 2, 5)
200
150
80
ns
13
TdTXD(TRX)
TxD to TRxC Delay
(Send Clock Echo)
200
140
80
ns
14a
TwRTXh
RTxC High Width (Note 6)
150
120
80
ns
14b
TwRTxh(E)
RTxC High Width (Note 9)
50
40
15.6
ns
15a
TwRTXI
RTxC Low Width (Note 6)
150
120
80
ns
15b
TwRTXl(E)
RTxC Low Width (Note 9)
50
40
15.6
ns
16a
TcRTX
RTxC Cycle Time (Notes 6, 7)
488
400
244
ns
16b
TcRTx(E)
RTxC Cycle Time (Note 9)
125
100
31.25
ns
17
TcRTXX
Crystal Oscillator Period (Note 3)
125
18
TwTRXh
TRxC High Width (Note 6)
150
120
80
ns
19
TwTRXI
TRxC Low Width (Note 6)
150
120
80
ns
20
TcTRX
TRxC Cycle Time (Notes 6, 7)
488
400
244
ns
21
TwEXT
DCD or CTS Pulse Width
200
120
70
ns
NA
NA
1000
NA
100
NA
1000
NA
62
NA
1000
ns
22
TwSY
SYNC Pulse Width
200
120
70
ns
Notes:
1. RxC is RTxC or TRxC, whichever is supplying the receive clock.
2. TxC is TRxC or RTxC, whichever is supplying the transmit clock.
3. Both RTxC and SYNC have 30-pF capacitors to ground connected to them.
4. Parameter applies only if the data rate is one-fourth the PCLK rate. In all other cases, no phase relationship between
RxC and PCLK or TxC and PCLK is required.
5. Parameter applies only to FM encoding/decoding.
6. Parameter applies only for transmitter and receiver; DPLL and baud rate generator timing requirements are identical to
chip PCLK requirements.
7. The maximum receive or transmit data is 1/4 PCLK.
8. External PCLK to RxC or TxC synchronization requirement eliminated for PCLK divide-by-four operation.
TRxC and RTxC rise and fall times are identical to PCLK. Reference timing specs Tfpc and Trpc.
Tx and Rx input clock slow rates should be kept to a maximum of 30 ns. All parameters related to input CLK edges
should be referenced at the point at which the transition begins or ends, whichever is the worst case.
9. ENHANCED FEATURE—RTxC used as input to internal DPLL only.
Am85C30
47
AMD
SWITCHING CHARACTERISTICS over MILITARY/INDUSTRIAL operating range (continued)
System Timing (see Figure 20)
No.
Parameter
Symbol
8.192 MHz
Parameter
Description
10 MHz
Min
Max
Min
Max
Unit
1
TdRXC(REQ)
RXC ↑ W/REQ Valid Delay
(Note 2)
8
12
8
12
TcPc
2
TdRXC(W)
RXC ↑ to Wait Inactive Delay
(Notes 1, 2)
8
14
8
14
TcPc
3
TdRXC(SY)
RxC ↑ to SYNC Valid Delay
(Note 2)
4
7
4
7
TcPc
4
TdRXC(INT)
RxC ↑ to INT Valid Delay
(Notes 1, 2)
10
16
10
16
TcPc
5
TdTXC(REQ)
TxC ↓ to W/REQ Valid Delay
(Note 3)
5
8
5
8
TcPc
6
TdTXC(W)
TxC ↓ to Wait Inactive Delay
(Notes 1, 3)
5
11
5
11
TcPc
7a
TdTXC(DRQ)
TxC ↓ to DTR/REQ Valid Delay
(Note 3)
4
7
4
7
TcPc
7b
TdTXC(EDRQ)
TxC ↓ to DTR/REQ Valid Delay
(Notes 3, 4)
5
8
5
8
TcPc
8
TdTXC(INT)
TxC ↓ to INT Valid Delay
(Notes 1, 3)
6
10
6
10
TcPc
9
TdSY(INT)
SYNC Transition to INT Valid
Delay (Note 1)
2
6
2
6
TcPc
10
TdEXT(INT)
DCD or CTS Transition to INT
Valid Delay (Note 1)
2
6
2
6
TcPc
Min
Max
Unit
Parameter
Description
16.384 MHz
No.
Parameter
Symbol
1
TdRXC(REQ)
RXC ↑ W/REQ Valid Delay
(Note 2)
8
12
TcPc
2
TdRXC(W)
RXC ↑ to Wait Inactive Delay
(Notes 1, 2)
8
14
TcPc
3
TdRXC(SY)
RxC ↑ to SYNC Valid Delay
(Note 2)
4
7
TcPc
4
TdRXC(INT)
RxC ↑ to INT Valid Delay
(Notes 1, 2)
10
16
TcPc
5
TdTXC(REQ)
TxC ↓ to W/REQ Valid Delay
(Note 3)
5
8
TcPc
6
TdTXC(W)
TxC ↓ to Wait Inactive Delay
(Notes 1, 3)
5
11
TcPc
7a
TdTXC(DRQ)
TxC ↓ to DTR/REQ Valid Delay
(Note 3)
4
7
TcPc
7b
TdTXC(EDRQ)
TxC ↓ to DTR/REQ Valid Delay
(Notes 3, 4)
5
8
TcPc
8
TdTXC(INT)
TxC ↓ to INT Valid Delay
(Notes 1, 3)
6
10
TcPc
9
TdSY(INT)
SYNC Transition to INT Valid
Delay (Note 1)
2
6
TcPc
10
TdEXT(INT)
DCD or CTS Transition to INT
Valid Delay (Note 1)
2
6
TcPc
Notes:
1. Open-drain output, measured with open-drain test load.
2. RxC is RTxC or TRxC, whichever is supplying the receive clock.
3. TxC is TRxC or RTxC, whichever is supplying the transmit clock.
4. Parameter applies to Enhanced Request mode only.
48
Am85C30
AMD
SWITCHING CHARACTERISTICS over MILITARY/INDUSTRIAL operating range (continued)
Read and Write Timing (see Figure 21)
No.
Parameter
Symbol
8.192 MHz
Parameter
Description
Min
Max
10 MHz
Min
Max
16.384 MHz
Min
Max
Unit
1
TwPCI
PCLK Low Width
50
1000
40
1000
26
1000
ns
2
TwPCh
PCLK High Width
50
1000
40
1000
26
1000
ns
3
TfPC
PCLK Fall Time
15
12
8
ns
4
TrPC
PCLK Rise Time
15
12
8
ns
5
TcPC
PCLK Cycle Time
122
6
TsA(WR)
Address to WR ↓ Setup Time
70
7
ThA(WR)
Address to WR ↑ Hold Time
0
0
0
ns
8
TsA(RD)
Address to RD ↓ Setup Time
70
50
35
ns
2000
100
2000
50
61
2000
35
ns
ns
9
ThA(RD)
Address to RD ↑ Hold Time
0
0
0
ns
10
TsIA(PC)
INTACK to PCLK ↑ Setup Time
20
20
15
ns
11
TsIA(WR)
INTACK to WR ↓ Setup Time
(Note 1)
145
120
70
ns
12
ThIA(WR)
INTACK to WR ↑ Hold Time
0
0
0
ns
13
TsIA(RD)
INTACK to RD ↓ Setup Time
(Note 1)
145
120
70
ns
14
ThIAi(RD)
INTACK to RD ↑ Hold Time
0
0
0
ns
15
ThIA(PC)
INTACK to PCLK ↑ Hold Time
40
30
15
ns
16
TsCEI(WR)
CE Low to WR ↓ Setup Time
0
0
0
ns
17
ThCE(WR)
CE to WR ↑ Hold Time
0
0
0
ns
18
TsCEh(WR)
CE High to WR ↓ Setup Time
60
50
30
ns
19
TsCEI(RD)
CE Low to RD ↓ Setup Time
(Note 1)
0
0
0
ns
20
ThCE(RD)
CE to RD ↑ Hold Time (Note1)
0
0
0
ns
21
TsCEh(RD)
CE High to RD ↓ Setup Time
(Note 1)
60
50
30
ns
22
TwRDI
RD Low Width (Note 1)
150
125
75
ns
23
TdRD(DRA)
RD ↓ to Read Data Active Delay
0
0
0
ns
24
TdRDr(DR)
RD ↑ to Read Data Not Valid Delay
0
0
0
ns
25
TdRDf(DR)
RD ↓ to Read Data Valid Delay
140
125
70
ns
26
TdRD(DRz)
RD ↑ to Read Data Float Delay
(Note 2)
40
35
20
ns
Notes:
1. Parameter does not apply to Interrupt Acknowledge transactions.
2. Float delay is defined as the time at which the data bus is released from its drive state with a maximum DC load and
minimum AC load.
Am85C30
49
AMD
SWITCHING CHARACTERISTICS over MILITARY/INDUSTRIAL operating range (continued)
Interrupt Acknowledge Timing, Reset Timing, Cycle Timing (see Figures 22–24)
No.
Parameter
Symbol
8.192 MHz
Parameter
Description
Min
Max
10 MHz
Min
220
Max
16.384 MHz
Min
Unit
100
ns
TdA(DR)
Address Required Valid to Read
Data Valid Delay
28
TwWRI
WR Low Width
29
TdWRf(DW)
WR ↓ to Write Data Valid
30
ThDW(WR)
Write Data to WR ↑ Hold Time
31
TdWR(W)
WR ↓ to Wait Valid Delay (Note 2)
170
100
50
ns
32
TdRD(W)
RD ↓ to Wait Valid Delay (Note 2)
170
100
50
ns
33
TdWRf(REQ)
WR ↓ to W/REQ Not Valid Delay
170
120
70
ns
34
TdRDf(REQ)
RD ↓ to W/REQ Not Valid Delay
170
120
70
ns
35a
TdWRr(REQ)
WR ↓ to DTR/REQ Not Valid Delay
4.0TcPc
4.0TcPc
35b
TdWRr(EREQ)
WR ↓ to DTR/REQ Not Valid Delay
120
120
70
ns
36
TdRDr(REQ)
RD ↑ to DTR/REQ Not Valid Delay
NA
NA
NA
ns
37
TdPC(INT)
PCLK ↓ to INT Valid Delay (Note 2)
175
ns
38
TdIAi(RD)
INTACK to RD ↓ (Acknowledge)
Delay (Note 3)
150
39
TwRDA
RD (Acknowledge) Width
150
40
TdRDA(DR)
RD ↓ (Acknowledge) to Read
Data Valid Delay
41
TsIEI(RDA)
IEI to RD ↓ (Acknowledge) Setup
Time
95
80
50
ns
42
ThIEI(RDA)
IEI to RD ↑ (Acknowledge) Hold
Time
0
0
0
ns
43
TdIEI(IEO)
IEI to IEO Delay Time
44
TdPC(IEO)
PCLK ↑ to IEO Delay
200
175
80
ns
45
TdRDA(INT)
RD ↓ to INT Inactive Delay (Note 2)
450
320
200
ns
46
TdRD(WRQ)
RD ↑ to WR ↓ Delay for No Reset
15
15
10
ns
47
TdWRQ(RD)
WR ↑ to RD ↓ Delay for No Reset
15
15
10
ns
48
TwRES
WR and RD Coincident Low for
Reset
150
100
75
ns
49
Trc
Valid Access Recovery Time
(Note 1)
3.5
3.5
3.5
TcPc
150
160
Max
27
125
35
0
75
35
0
500
20
0
ns
75
120
95
ns
50
125
ns
4.0TcPc ns
400
125
140
ns
ns
70
80
45
ns
ns
Notes:
1 Parameter applies only between transactions involving the ESCC, if WR/RD falling edge is synchronized to PCLK
falling edge, then TrC = 3TcPc.
2. Open-drain output, measured with open-drain test load.
3. Parameter is system dependent. For any SCC in the daisy chain, TdIAi(RD) must be greater than the sum of DdPC(IEO)
for the highest priority device in the daisy chain, TsIEI(RDA) for the SCC, and TdIEI(IEO) for each device separating
them in the daisy chain.
4. Parameter applies to Enhanced Request mode only.
50
Am85C30
AMD
PHYSICAL DIMENSIONS*
CD 040
2.035
2.080
.098
MAX
.565
.605
1
.050
.065
.005
MIN
.100
BSC
TOP VIEW
.590
.615
.008
.012
.160
.220
.015
.060
0°
15°
.125
.160
.015
.022
SIDE VIEW
.150
MIN
.700
MAX
06824D
BZ13 CD 040
5/20/92 c dc
END VIEW
*For reference only. BSC is an ANSI standard for Basic Space Centering.
Am85C30
51
AMD
PHYSICAL DIMENSIONS
CL 044
.500
BSC
.250
BSC
.050
BSC
.250
BSC
.045
.055
.500
BSC
.006
.022
.022
.028
.015
MIN
.003
.015
.640
.660
.040 X 45° REF. (3x)
(OPTIONAL)
.640
.660
.054
.088
.625
BSC
.064
.100
.625
BSC
INDEX CORNER
.020 X 45° REF.
(OPTIONAL)
PLANE 2
PLANE 1
52
Am85C30
06825E
AW 29
8/15/91 c dc
AMD
PHYSICAL DIMENSIONS
PD 040
2.040
2.080
.530
.580
1
.045
.065
.005
MIN
.090
.110
TOP VIEW
.600
.625
.140
.225
.008
.015
.015
.060
.120
.160
0°
7°
.014
.022
.630
.700
06823E
CJ76 PD 040
1/21/93 c dc
END VIEW
SIDE VIEW
PL 044
.042
.048
.020
MIN
.050
REF
.042
.056
.025
R
.045
.026
.032
.013
.021
.685 .650
.695 .656
.500 .590
REF .630
.009
.015
.650
.656
.685
.695
.165
.180
TOP VIEW
.090
.120
06752F
CJ48 PL 044
1/21/93 c dc
SIDE VIEW
Trademarks
Copyright  1993 Advanced Micro Devices, Inc. All rights reserved.
AMD is a registered trademark of Advanced Micro Devices, Inc.
Product names used in this publication are for identification purposes only and may be trademarks of their respective companies.
Am85C30
53
AMENDMENT
Advanced
Micro
Devices
Am85C30
Enhanced Serial Communications Controller
SUMMARY
This amendment adds information to the Final Data
Sheet on the Commercial and Industrial 20 MHz speed
grades. This latest offering complements the 8, 10, and
16 MHz speed grades currently offered by AMD.
A few minor inaccuracies are also corrected and a clarification section on Hardware Reset in Software that had
been previously available as a separate page is now reprinted here for ease of reference.
DETAILS
Pages 39 and 47: SWITCHING
CHARACTERISTICS
Page 1:
DISTINCTIVE CHARACTERISTICS
■ Add 20 MHz/5.0 Mbyte/s under “Fastest data rate
of any Am85C30” bullet.
Page 4: Ordering Information, Commodity
Products
■ Change word from “Commodity” to “Standard”
■ Add Am85C30-20 to valid combinations and
-20 = 20 MHz to SPEED OPTION
Page 5:
Ordering Information, Industrial Products
■ Add Am85C30-20 to valid combinations and
-20 = 20 MHz to SPEED OPTION
■ In note 8 change from “clock slow rates” to “clock
slew rates”.
Pages 39–50:
SWITCHING CHARACTERISTICS
■ Add minimum and maximum limits, where appropriate, for the 20 MHz speed grade now being
offered.
Note: Minor corrections should be made on the existing data sheets. However, for ease of use, pages
38–50 as well as the page on Hardware Reset in Software are printed with this amendment.
■ Change package description from “J = 44-Pin
Leadless Chip Carrier (PL 044) ” to “J = 44-Pin
Plastic Leaded Chip Carrier (PL 044) ”.
Page 38: DC CHARACTERISTICS
■ Delete ICC1 for the 12 MHz speed grade since this
speed is not offered.
■ Add ICC1 for the 20 MHz speed grade now being
offered.
■ Change symbol from “CMO” to “CI/O” and add note
on Capacitance.
Publication# 10216 Rev. F Amendment /1
Issue Date: December 1993
AMD
AMENDMENT
ABSOLUTE MAXIMUM RATINGS
OPERATING RANGES
Storage Temperature . . . . . . . . . . . –65°C to +150°C
Commercial (C) Devices
Ambient Temperature (TA) . . . . . . . . . . 0°C to +70°C
Supply Voltage (VCC) . . . . . . . . . . . . . . . . +5 V ± 10%
Voltage at any Pin
Relative to VSS . .
. . . . . . . . . . . . . –0.5 to +7.0 V
Stresses above those listed under Absolute Maximum Ratings may cause permanent device failure. Functionality at or
above these limits is not implied. Exposure to absolute maximum ratings for extended periods may affect device reliability.
Industrial (I) Devices
Ambient Temperature (TA) . . . . . . . . –40°C to +85°C
Supply Voltage (VCC) . . . . . . . . . . . . . . . . . 5 V ± 10%
Military (M) Devices
Case Temperature (TC) . . . . . . . . . –55°C to +125°C
Supply Voltage (VCC) . . . . . . . . . . . . . . . . . 5 V ± 10%
Operating ranges define those limits between which the functionality of the device is guaranteed.
DC CHARACTERISTICS over operating range unless otherwise specified
Parameter
Symbol
Parameter
Description
Test Conditions
Min
Max
Unit
VIH
Input High Voltage
2.2
VCC +0.3*
V
VIL
Input Low Voltage
–0.3*
0.8
V
VOH1
Output High Voltage
IOH = –1.6 mA
2.4
V
VOH2
Output High Voltage
IOH = –250 µA
VCC –0.8
V
VOL
Output Low Voltage
IOL = +2.0 mA
IIL
Input Leakage
IOL
ICC1
CIN**
0.4
V
0.4 V ≤ VIN ≤ 2.4 V
±10.0
µA
Output Leakage
0.4 V ≤ VOUT ≤ 2.4 V
±10.0
µA
VCC Supply Current
8.192 MHz
10 MHz
16.384 MHz
20 MHz
18
18
22
22
mA
mA
mA
mA
10
pF
15
pF
20
pF
Input Capacitance
COUT**
Output Capacitance
CI/O**
Bidirectional Capacitance
Inputs at
voltage rails,
output unloaded
Unmeasured pins returned
to ground = 1 MHz over
specified temperature range
*VIH Max and VIL Min not tested. Guaranteed by design.
**These parameters are not 100% tested, but are evaluated at initial characterization and at any time the design is modified
where capacitance may be affected.
Standard Test Conditions
The characteristics below apply for the following standard test conditions, unless otherwise noted. All
voltages are referenced to GND. Positive current flows
into the referenced pin. Standard conditions are as
follows:
+4.5 V ≤ VCC ≤ +5.5 V
GND = 0 V
0°C ≤ TA ≤ 70°C
SWITCHING TEST CIRCUITS
Standard Test Dynamic Load Circuit
Open-Drain Test Load
+5 V
IO L = 2 mA
Threshold
Voltage
VT = 1.4 V
2.2K
From Output
Under Test
75 pF
From Output
Under Test
75 pF
IOH = 250 µA
10216F/1-1
2
10216F/1-2
Am85C30
AMD
AMENDMENT
SWITCHING CHARACTERISTICS over COMMERCIAL operating range unless otherwise
specified—General Timing (see Figure 19)
8.192 MHz
10 MHz
16.384 MHz
20 MHz
No.
Parameter
Symbol
Parameter
Description
1
TdPC(REQ)
PCLK ↓ to W/REQ Valid Delay
2
TdPC(W)
PCLK ↓ to Wait Inactive Delay
3
TsRXC(PC)
RxC ↑ to PCLK ↑ Setup Time
(Notes 1, 4 & 8)
4
TsRXD(RXCr)
RxD to RxC ↑ Setup Time
(Xl Mode) (Note 1)
0
0
0
0
ns
5
ThRXD(RXCr)
RxD to RxC ↑ Hold Time
(Xl Mode) (Note 1)
150
125
50
45
ns
6
TsRXD(RXCf)
RxD to RxC ↓ Setup Time
(Xl Mode) (Notes 1, 5)
0
0
0
0
ns
7
ThRXD(RXCf)
RxD to RxC ↓ Hold Time
(Xl Mode) (Notes 1, 5)
150
125
50
45
ns
8
TsSY(RXC)
SYNC to RxC ↑ Setup Time
(Note 1)
–200
–150
–100
–90
ns
9
ThSY(RXC)
SYNC to RxC ↑ Hold Time
(Note 1)
5TcPc
5TcPc
5TcPc
5TcPc
ns
10
TsTXC(PC)
TxC ↓ to PCLK ↑ Setup Time
(Notes 2, 4 & 8)
NA
NA
NA
NA
11
TdTXCf(TXD)
TxC ↓ to TxD Delay (Xl Mode)
(Note 2)
200
150
80
70
ns
12
TdTXCr(TXD)
TxC ↑ to TxD Delay (Xl Mode)
(Notes 2, 5)
200
150
80
70
ns
13
TdTXD(TRX)
TxD to TRxC Delay
(Send Clock Echo)
200
140
80
70
ns
14a
TwRTXh
RTxC High Width (Note 6)
14b
TwRTxh(E)
RTxC High Width (Note 9)
15a
TwRTXI
RTxC Low Width (Note 6)
15b
TwRTXl(E)
RTxC Low Width (Note 9)
16a
TcRTX
16b
TcRTx(E)
17
18
Min
Max
Min
250
NA
150
Min
150
350
NA
Max
NA
Min
80
250
NA
Max
180
NA
NA
NA
Max Unit
70
ns
170
ns
NA
ns
120
80
70
50
40
15.6
15.6
ns
150
120
80
70
ns
50
40
15.6
15.6
ns
RTxC Cycle Time (Notes 6, 7)
488
400
244
200
ns
RTxC Cycle Time (Note 9)
125
100
31.25
31.25
ns
TcRTXX
Crystal Oscillator Period (Note 3)
125
TwTRXh
TRxC High Width (Note 6)
150
120
19
TwTRXI
TRxC Low Width (Note 6)
150
120
20
TcTRX
TRxC Cycle Time (Notes 6, 7)
488
400
21
TwEXT
DCD or CTS Pulse Width
200
120
70
1000
100
1000
62
80
1000
61
ns
1000
ns
70
ns
80
70
ns
244
200
ns
60
ns
22 TwSY
SYNC Pulse Width
200
120
70
60
ns
Notes:
1. RxC is RTxC or TRxC, whichever is supplying the receive clock.
2. TxC is TRxC or RTxC, whichever is supplying the transmit clock.
3. Both RTxC and SYNC have 30-pF capacitors to ground connected to them.
4. Parameter applies only if the data rate is one-fourth the PCLK rate. In all other cases, no phase relationship between
RxC and PCLK or TxC and PCLK is required.
5. Parameter applies only to FM encoding/decoding.
6. Parameter applies only for transmitter and receiver; DPLL and baud rate generator timing requirements are identical to
chip PCLK requirements.
7. The maximum receive or transmit data is 1/4 PCLK.
8. External PCLK to RxC or TxC synchronization requirement eliminated for PCLK divide-by-four operation.
TRxC and RTxC rise and fall times are identical to PCLK. Reference timing specs Tfpc and Trpc.
Tx and Rx input clock slew rates should be kept to a maximum of 30 ns. All parameters related to input CLK edges
should be referenced at the point at which the transition begins or ends, whichever is the worst case.
9. ENHANCED FEATURE—RTxC used as input to internal DPLL only.
Am85C30
3
AMD
AMENDMENT
SWITCHING TEST INPUT/OUTPUT WAVEFORM
2.4 V
2.0 V
0.8 V
0.4 V
2.0 V
Test
Points
0.8 V
10216F/1-3
AC testing: Inputs are driven at 2.4 V for a logic 1 and 0.4 V for a logic 0.
Timing measurements are made at 2.0 V for a logic 1 and 0.8 V for logic 0.
PCLK
1
W/REQ
Request
2
W/REQ
Wait
3
RTxC, TRxC
Receive
4
5
6
7
RxD
8
9
SYNC
External
10
TRxC RTxC
Transmit
12
11
TxD
13
TRxC
Output
14
15
RTxC
16
17
TRxC
18
19
20
CTS, DCD, R1
21
21
22
22
SYNC
Input
10216F/1-4
Figure 19. General Timing
4
Am85C30
AMD
AMENDMENT
SWITCHING CHARACTERISTICS over COMMERCIAL operating range (continued)
System Timing (see Figure 20)
Parameter
Symbol
10 MHz
8.192 MHz
Parameter
Description
Min
Max
Min
Max
Unit
1
TdRXC(REQ)
RXC ↑ W/REQ Valid Delay
(Note 2)
8
12
8
12
TcPc
2
TdRXC(W)
RXC ↑ to Wait Inactive Delay
(Notes 1, 2)
8
14
8
14
TcPc
3
TdRXC(SY)
RxC ↑ to SYNC Valid Delay
(Note 2)
4
7
4
7
TcPc
4
TdRXC(INT)
RxC ↑ to INT Valid Delay
(Notes 1, 2)
10
16
10
16
TcPc
5
TdTXC(REQ)
TxC ↑ to W/REQ Valid Delay
(Note 3)
5
8
5
8
TcPc
6
TdTXC(W)
TxC ↓ to Wait Inactive Delay
(Notes 1, 3)
5
11
5
11
TcPc
7a
TdTXC(DRQ)
TxC ↓ to DTR/REQ Valid Delay
(Note 3)
4
7
4
7
TcPc
7b
TdTXC(EDRQ)
TxC ↓ to DTR/REQ Valid Delay
(Notes 3, 4)
5
8
5
8
TcPc
8
TdTXC(INT)
TxC ↓ to INT Valid Delay
(Notes 1, 3)
6
10
6
10
TcPc
9
TdSY(INT)
SYNC Transition to INT Valid
Delay (Note 1)
2
6
2
6
TcPc
10
TdEXT(INT)
DCD or CTS Transition to INT
Valid Delay (Note 1)
2
6
2
6
TcPc
No.
No.
Parameter
Symbol
16.384 MHz
Parameter
Description
Min
20 MHz
Max
Min
Max
Unit
1
TdRXC(REQ)
RXC ↑ W/REQ Valid Delay
(Note 2)
8
12
8
12
TcPc
2
TdRXC(W)
RXC ↑ to Wait Inactive Delay
(Notes 1, 2)
8
14
8
14
TcPc
3
TdRXC(SY)
RxC ↑ to SYNC Valid Delay
(Note 2)
4
7
4
7
TcPc
4
TdRXC(INT)
RxC ↑ to INT Valid Delay
(Notes 1, 2)
10
16
10
16
TcPc
5
TdTXC(REQ)
TxC ↓ to W/REQ Valid Delay
(Note 3)
5
8
5
8
TcPc
6
TdTXC(W)
TxC ↓ to Wait Inactive Delay
(Notes 1, 3)
5
11
5
11
TcPc
7a
TdTXC(DRQ)
TxC ↓ to DTR/REQ Valid Delay
(Note 3)
4
7
4
7
TcPc
7b
TdTXC(EDRQ)
TxC ↓ to DTR/REQ Valid Delay
(Notes 3, 4)
5
8
5
8
TcPc
8
TdTXC(INT)
TxC ↓ to INT Valid Delay
(Notes 1, 3)
6
10
6
10
TcPc
9
TdSY(INT)
SYNC Transition to INT Valid
Delay (Note 1)
2
6
2
6
TcPc
10
TdEXT(INT)
DCD or CTS Transition to INT
Valid Delay (Note 1)
2
6
2
6
TcPc
Notes:
1. Open-drain output, measured with open-drain test load.
2. RxC is RTxC or TRxC, whichever is supplying the receive clock.
3. TxC is TRxC or RTxC, whichever is supplying the transmit clock.
4. Parameter applies to Enhanced Request mode only.
Am85C30
5
AMD
AMENDMENT
SWITCHING CHARACTERISTICS over COMMERCIAL operating range (continued)
Read and Write Timing (see Figure 21)
No.
Parameter
Symbol
8.192 MHz
Parameter
Description
10 MHz
16.384 MHz
20 MHz
Min
Max
Min
Max
Min
Max
Min
Max Unit
1
TwPCI
PCLK Low Width
50
2000
40
2000
26
2000
22
2000
ns
2
TwPCh
PCLK High Width
50
2000
40
2000
26
2000
22
2000
ns
3
TfPC
PCLK Fall Time
15
12
8
5
ns
4
TrPC
PCLK Rise Time
15
12
8
5
ns
5
TcPC
PCLK Cycle Time
122
2000
ns
6
TsA(WR)
Address to WR ↓ Setup Time
70
7
ThA(WR)
Address to WR ↑ Hold Time
0
0
0
0
ns
8
TsA(RD)
Address to RD ↓ Setup Time
70
50
35
30
ns
4000
100
4000
50
61
4000
35
50
30
ns
9
ThA(RD)
Address to RD ↑ Hold Time
0
0
0
0
ns
10
TsIA(PC)
INTACK to PCLK ↑ Setup Time
20
20
15
15
ns
11
TsIA(WR)
INTACK to WR ↓ Setup Time
(Note 1)
145
120
70
65
ns
12
ThIA(WR)
INTACK to WR ↑ Hold Time
0
0
0
0
ns
13
TsIA(RD)
INTACK to RD ↓ Setup Time
(Note 1)
145
120
70
65
ns
14
ThIAi(RD)
INTACK to RD ↑ Hold Time
0
0
0
0
ns
15
ThIA(PC)
INTACK to PCLK ↑ Hold Time
40
30
15
15
ns
16
TsCEI(WR)
CE Low to WR ↓ Setup Time
0
0
0
0
ns
17
ThCE(WR)
CE to WR ↑ Hold Time
0
0
0
0
ns
18
TsCEh(WR)
CE High to WR ↓ Setup Time
60
50
30
25
ns
19
TsCEI(RD)
CE Low to RD ↓ Setup Time
(Note 1)
0
0
0
0
ns
20
ThCE(RD)
CE to RD ↑ Hold Time (Note1)
0
0
0
0
ns
21
TsCEh(RD)
CE High to RD ↓ Setup Time
(Note 1)
60
50
30
25
ns
22
TwRDI
RD Low Width (Note 1)
150
125
75
65
ns
23
TdRD(DRA)
RD ↓ to Read Data Active Delay
0
0
0
0
ns
24
TdRDr(DR)
RD ↑ to Read Data Not Valid Delay
0
0
0
0
25
TdRDf(DR)
RD ↓ to Read Data Valid Delay
140
120
70
65
ns
26
TdRD(DRz)
RD ↑ to Read Data Float Delay
(Note 2)
40
35
20
20
ns
ns
Notes:
1. Parameter does not apply to Interrupt Acknowledge transactions.
2. Float delay is defined as the time at which the data bus is released from its drive state with a maximum DC load and
minimum AC load.
6
Am85C30
AMD
AMENDMENT
RTxC TRxC
Receive
W/REQ
Request
1
W/REQ
Wait
2
SYNC
Output
3
INT
4
RTxC
TRxC
Transmit
W/REQ
Request
5
W/REQ
Wait
6
DTR REQ
Request
7
INT
8
CTS, DCD, RI
SYNC
Input
9
INT
10
10216F/1-5
Figure 20. System Timing
Am85C30
7
AMD
AMENDMENT
1
PCLK
2
3
5
6
4
A/B, D/C
7
10
8
9
INTACK
11
10
12
13
14
15
CE
16
18
RD
21
19
22
20
D0–D7
Read
Valid
17
23
24
25
27
26
WR
28
D0–D7
Write
Valid
29
31
30
W/REQ
Wait
32
W/REQ
Request
35
33
DTR/REQ
Request
34
36
INT
37
10216F/1-6
Figure 21. Read and Write Timing
8
Am85C30
AMD
AMENDMENT
SWITCHING CHARACTERISTICS over COMMERCIAL operating range (continued)
Interrupt Acknowledge Timing, Reset Timing, Cycle Timing (see Figures 22–24)
No.
Parameter
Symbol
8.192 MHz
Parameter
Description
Min
Max
10 MHz
Min
220
Max
16.384 MHz
Min
Min
TdA(DR)
Address Required Valid to Read
Data Valid Delay
28
TwWRI
WR Low Width
29
TdWRf(DW)
WR ↓ to Write Data Valid
30
ThDW(WR)
Write Data to WR ↑ Hold Time
31
TdWR(W)
WR ↓ to Wait Valid Delay (Note 2)
170
100
50
50
ns
32
TdRD(W)
RD ↓ to Wait Valid Delay (Note 2)
170
100
50
50
ns
33
TdWRf(REQ)
WR ↓ to W/REQ Not Valid Delay
170
120
70
65
ns
65
ns
125
35
0
100
Max Unit
27
150
160
Max
20 MHz
75
35
0
90
65
20
0
ns
ns
20
0
ns
ns
34
TdRDf(REQ)
RD ↓ to W/REQ Not Valid Delay
170
120
70
35a
TdWRr(REQ)
WR ↓ to DTR/REQ Not Valid Delay
4TcPc
4TcPc
4TcPc
35b
TdWRr(EREQ)
WR ↓ to DTR/REQ Not Valid Delay
120
120
70
65
ns
36
TdRDr(REQ)
RD ↑ to DTR/REQ Not Valid Delay
NA
NA
NA
NA
ns
37
TdPC(INT)
PCLK ↓ to INT Valid Delay (Note 2)
38
TdIAi(RD)
INTACK to RD ↓ (Acknowledge)
Delay (Note 3)
150
39
TwRDA
RD (Acknowledge) Width
150
40
TdRDA(DR)
RD ↓ (Acknowledge) to Read
Data Valid Delay
41
TsIEI(RDA)
IEI to RD ↓ (Acknowledge) Setup
Time
95
80
50
45
ns
42
ThIEI(RDA)
IEI to RD ↑ (Acknowledge) Hold
Time
0
0
0
0
ns
43
TdIEI(IEO)
IEI to IEO Delay Time
95
80
45
40
ns
44
TdPC(IEO)
PCLK ↑ to IEO Delay
200
175
80
70
ns
180
ns
500
400
125
45
TdRDA(INT)
RD ↓ to INT Inactive Delay (Note 2)
46
TdRD(WRQ)
RD ↑ to WR ↓ Delay for No Reset
47
TdWRQ(RD)
WR ↑ to RD ↓ Delay for No Reset
48
TwRES
WR and RD Coincident Low for
Reset
49
Trc
Valid Access Recovery Time
(Note 1)
3.5
160
45
75
120
450
15
175
50
125
140
4TcPc ns
65
70
320
ns
60
200
ns
ns
ns
15
10
10
ns
15
15
10
10
ns
150
100
75
65
ns
3.5
3.5
3.5
TcPc
Notes:
1 Parameter applies only between transactions involving the ESCC, if WR/RD falling edge is synchronized to PCLK
falling edge, then TrC = 3TcPc.
2. Open-drain output, measured with open-drain test load.
3. Parameter is system dependent. For any SCC in the daisy chain, TdIAi(RD) must be greater than the sum of DdPC(IEO)
for the highest priority device in the daisy chain, TsIEI(RDA) for the SCC, and TdIEI(IEO) for each device separating
them in the daisy chain.
4. Parameter applies to Enhanced Request mode only.
Am85C30
9
AMD
AMENDMENT
WR
46
48
47
RD
10216F/1-7
Figure 22. Reset Timing
CE
49
RD or WR
10216F/1-8
Figure 23. Cycle Timing
PCLK
10
15
INTACK
14
10
38
RD
39
23
24
D0–D7
Valid
40
26
42
41
IEI
43
44
IEO
45
INT
10216F/1-9
Figure 24. Interrupt Acknowledge Timing
10
Am85C30
AMD
AMENDMENT
SWITCHING CHARACTERISTICS over MILITARY/INDUSTRIAL operating range unless
otherwise specified—General Timing (see Figure 19)
8.192 MHz
10 MHz
16.384 MHz
20 MHz
Industrial Only
No.
Parameter
Symbol
Parameter
Description
1
TdPC(REQ)
PCLK ↓ to W/REQ Valid Delay
250
150
80
70
ns
2
TdPC(W)
PCLK ↓ to Wait Inactive Delay
350
250
180
170
ns
3
TsRXC(PC)
RxC ↑ to PCLK ↑ Setup Time
(Notes 1, 4 & 8)
NA
ns
4
TsRXD(RXCr)
RxD to RxC ↑ Setup Time
(Xl Mode) (Note 1)
0
0
0
0
ns
5
ThRXD(RXCr)
RxD to RxC ↑ Hold Time
(Xl Mode) (Note 1)
150
125
50
45
ns
6
TsRXD(RXCf)
RxD to RxC ↓ Setup Time
(Xl Mode) (Notes 1, 5)
0
0
0
0
ns
7
ThRXD(RXCf)
RxD to RxC ↓ Hold Time
(Xl Mode) (Notes 1, 5)
150
125
50
45
ns
8
TsSY(RXC)
SYNC to RxC ↑ Setup Time
(Note 1)
–200
–150
–100
–90
ns
9
ThSY(RXC)
SYNC to RxC ↑ Hold Time
(Note 1)
5TcPc
5TcPc
5TcPc
5TcPc
ns
10
TsTXC(PC)
TxC ↓ to PCLK ↑ Setup Time
(Notes 2, 4 & 8)
NA
NA
NA
NA
11
TdTXCf(TXD)
TxC ↓ to TxD Delay (Xl Mode)
(Note 2)
200
150
80
70
ns
12
TdTXCr(TXD)
TxC ↑ to TxD Delay (Xl Mode)
(Notes 2, 5)
200
150
80
70
ns
13
TdTXD(TRX)
TxD to TRxC Delay
(Send Clock Echo)
200
140
80
70
ns
14a
TwRTXh
RTxC High Width (Note 6)
150
120
80
70
ns
14b
TwRTxh(E)
RTxC High Width (Note 9)
50
40
15.6
15.6
ns
15a
TwRTXI
RTxC Low Width (Note 6)
150
120
80
70
ns
15b
TwRTXl(E)
RTxC Low Width (Note 9)
50
40
15.6
15.6
ns
16a
TcRTX
RTxC Cycle Time (Notes 6, 7)
488
400
244
200
ns
16b
TcRTx(E)
RTxC Cycle Time (Note 9)
125
17
TcRTXX
Crystal Oscillator Period (Note 3)
125
18
TwTRXh
TRxC High Width (Note 6)
150
120
80
70
ns
19
TwTRXI
TRxC Low Width (Note 6)
150
120
80
70
ns
20
TcTRX
TRxC Cycle Time (Notes 6, 7)
488
400
244
200
ns
21
TwEXT
DCD or CTS Pulse Width
200
120
70
60
ns
Min
NA
Max
NA
Min
NA
Max
NA
100
1000
100
Min
NA
Max
NA
31.25
1000
62
Min
NA
Max Unit
31.25
1000
61
ns
1000
ns
22 TwSY
SYNC Pulse Width
200
120
70
60
ns
Notes:
1. RxC is RTxC or TRxC, whichever is supplying the receive clock.
2. TxC is TRxC or RTxC, whichever is supplying the transmit clock.
3. Both RTxC and SYNC have 30-pF capacitors to ground connected to them.
4. Parameter applies only if the data rate is one-fourth the PCLK rate. In all other cases, no phase relationship between
RxC and PCLK or TxC and PCLK is required.
5. Parameter applies only to FM encoding/decoding.
6. Parameter applies only for transmitter and receiver; DPLL and baud rate generator timing requirements are identical to
chip PCLK requirements.
7. The maximum receive or transmit data is 1/4 PCLK.
8. External PCLK to RxC or TxC synchronization requirement eliminated for PCLK divide-by-four operation.
TRxC and RTxC rise and fall times are identical to PCLK. Reference timing specs Tfpc and Trpc.
Tx and Rx input clock slew rates should be kept to a maximum of 30 ns. All parameters related to input CLK edges
should be referenced at the point at which the transition begins or ends, whichever is the worst case.
9. ENHANCED FEATURE—RTxC used as input to internal DPLL only.
Am85C30
11
AMD
AMENDMENT
SWITCHING CHARACTERISTICS over MILITARY/INDUSTRIAL operating range
(continued)—System Timing (see Figure 20)
Parameter
Symbol
Min
Max
Min
Max
Unit
1
TdRXC(REQ)
RXC ↑ W/REQ Valid Delay
(Note 2)
8
12
8
12
TcPc
2
TdRXC(W)
RXC ↑ to Wait Inactive Delay
(Notes 1, 2)
8
14
8
14
TcPc
3
TdRXC(SY)
RxC ↑ to SYNC Valid Delay
(Note 2)
4
7
4
7
TcPc
4
TdRXC(INT)
RxC ↑ to INT Valid Delay
(Notes 1, 2)
10
16
10
16
TcPc
5
TdTXC(REQ)
TxC ↑ to W/REQ Valid Delay
(Note 3)
5
8
5
8
TcPc
6
TdTXC(W)
TxC ↓ to Wait Inactive Delay
(Notes 1, 3)
5
11
5
11
TcPc
7a
TdTXC(DRQ)
TxC ↓ to DTR/REQ Valid Delay
(Note 3)
4
7
4
7
TcPc
7b
TdTXC(EDRQ)
TxC ↓ to DTR/REQ Valid Delay
(Notes 3, 4)
5
8
5
8
TcPc
8
TdTXC(INT)
TxC ↓ to INT Valid Delay
(Notes 1, 3)
6
10
6
10
TcPc
9
TdSY(INT)
SYNC Transition to INT Valid
Delay (Note 1)
2
6
2
6
TcPc
10
TdEXT(INT)
DCD or CTS Transition to INT
Valid Delay (Note 1)
2
6
2
6
TcPc
No.
No.
Parameter
Symbol
16.384 MHz
Parameter
Description
Min
Max
20 MHz
Industrial Only
Min
Max
Unit
1
TdRXC(REQ)
RXC ↑ W/REQ Valid Delay
(Note 2)
8
12
8
12
TcPc
2
TdRXC(W)
RXC ↑ to Wait Inactive Delay
(Notes 1, 2)
8
14
8
14
TcPc
3
TdRXC(SY)
RxC ↑ to SYNC Valid Delay
(Note 2)
4
7
4
7
TcPc
4
TdRXC(INT)
RxC ↑ to INT Valid Delay
(Notes 1, 2)
10
16
10
16
TcPc
5
TdTXC(REQ)
TxC ↓ to W/REQ Valid Delay
(Note 3)
5
8
5
8
TcPc
6
TdTXC(W)
TxC ↓ to Wait Inactive Delay
(Notes 1, 3)
5
11
5
11
TcPc
7a
TdTXC(DRQ)
TxC ↓ to DTR/REQ Valid Delay
(Note 3)
4
7
4
7
TcPc
7b
TdTXC(EDRQ)
TxC ↓ to DTR/REQ Valid Delay
(Notes 3, 4)
5
8
5
8
TcPc
8
TdTXC(INT)
TxC ↓ to INT Valid Delay
(Notes 1, 3)
6
10
6
10
TcPc
9
TdSY(INT)
SYNC Transition to INT Valid
Delay (Note 1)
2
6
2
6
TcPc
10
TdEXT(INT)
DCD or CTS Transition to INT
Valid Delay (Note 1)
2
6
2
6
TcPc
Notes:
1. Open-drain output, measured with open-drain test load.
2. RxC is RTxC or TRxC, whichever is supplying the receive clock.
3. TxC is TRxC or RTxC, whichever is supplying the transmit clock.
4. Parameter applies to Enhanced Request mode only.
12
10 MHz
8.192 MHz
Parameter
Description
Am85C30
AMD
AMENDMENT
SWITCHING CHARACTERISTICS over MILITARY/INDUSTRIAL operating range
(continued)
Read and Write Timing (see Figure 21)
No.
Parameter
Symbol
20 MHz
Parameter
Description
8.192 MHz
Min Max
10 MHz
Min Max
16.384 MHz
Min Max
Industrial Only
Min
Max Unit
1
TwPCI
PCLK Low Width
50
1000
40
1000
26
1000
22
1000
ns
2
TwPCh
PCLK High Width
50
1000
40
1000
26
1000
22
1000
ns
3
TfPC
PCLK Fall Time
15
12
8
5
ns
4
TrPC
PCLK Rise Time
15
12
8
5
ns
5
TcPC
PCLK Cycle Time
122
2000
ns
6
TsA(WR)
Address to WR ↓ Setup Time
70
7
ThA(WR)
Address to WR ↑ Hold Time
0
0
0
0
ns
8
TsA(RD)
Address to RD ↓ Setup Time
70
50
35
30
ns
9
ThA(RD)
Address to RD ↑ Hold Time
0
0
0
0
ns
10
TsIA(PC)
INTACK to PCLK ↑ Setup Time
20
20
15
15
ns
11
TsIA(WR)
INTACK to WR ↓ Setup Time
(Note 1)
145
120
70
65
ns
12
ThIA(WR)
INTACK to WR ↑ Hold Time
0
0
0
0
ns
13
TsIA(RD)
INTACK to RD ↓ Setup Time
(Note 1)
145
120
70
65
ns
14
ThIAi(RD)
INTACK to RD ↑ Hold Time
0
0
0
0
ns
15
ThIA(PC)
INTACK to PCLK ↑ Hold Time
40
30
15
15
ns
16
TsCEI(WR)
CE Low to WR ↓ Setup Time
0
0
0
0
ns
17
ThCE(WR)
CE to WR ↑ Hold Time
0
0
0
0
ns
18
TsCEh(WR)
CE High to WR ↓ Setup Time
60
50
30
25
ns
19
TsCEI(RD)
CE Low to RD ↓ Setup Time
(Note 1)
0
0
0
0
ns
2000
100
2000
50
61
2000
35
50
30
ns
20
ThCE(RD)
CE to RD ↑ Hold Time (Note1)
0
0
0
0
ns
21
TsCEh(RD)
CE High to RD ↓ Setup Time
(Note 1)
60
50
30
25
ns
22
TwRDI
RD Low Width (Note 1)
150
125
75
65
ns
23
TdRD(DRA)
RD ↓ to Read Data Active Delay
0
0
0
0
ns
24
TdRDr(DR)
RD ↑ to Read Data Not Valid Delay
0
25
TdRDf(DR)
RD ↓ to Read Data Valid Delay
140
125
70
65
ns
26
TdRD(DRz)
RD ↑ to Read Data Float Delay
(Note 2)
40
35
20
20
ns
0
0
0
ns
Notes:
1. Parameter does not apply to Interrupt Acknowledge transactions.
2. Float delay is defined as the time at which the data bus is released from its drive state with a maximum DC load and
minimum AC load.
Am85C30
13
AMD
AMENDMENT
SWITCHING CHARACTERISTICS over MILITARY/INDUSTRIAL operating range
(continued)
Interrupt Acknowledge Timing, Reset Timing, Cycle Timing (see Figures 22–24)
No.
Parameter
Symbol
8.192 MHz
Parameter
Description
Min
Max
10 MHz
Min
220
Max
16.384 MHz
Min
Min
TdA(DR)
Address Required Valid to Read
Data Valid Delay
28
TwWRI
WR Low Width
29
TdWRf(DW)
WR ↓ to Write Data Valid
30
ThDW(WR)
Write Data to WR ↑ Hold Time
31
TdWR(W)
WR ↓ to Wait Valid Delay (Note 2)
170
100
50
50
ns
32
TdRD(W)
RD ↓ to Wait Valid Delay (Note 2)
170
100
50
50
ns
33
TdWRf(REQ)
WR ↓ to W/REQ Not Valid Delay
170
120
70
65
ns
34
TdRDf(REQ)
RD ↓ to W/REQ Not Valid Delay
170
120
70
65
ns
35a
TdWRr(REQ)
WR ↓ to DTR/REQ Not Valid Delay
4TcPc
4TcPc
4TcPc
35b
TdWRr(EREQ)
WR ↓ to DTR/REQ Not Valid Delay
120
120
70
36
TdRDr(REQ)
RD ↑ to DTR/REQ Not Valid Delay
NA
NA
37
TdPC(INT)
PCLK ↓ to INT Valid Delay (Note 2)
500
400
38
TdIAi(RD)
INTACK to RD ↓ (Acknowledge)
Delay (Note 3)
150
125
50
45
ns
39
TwRDA
RD (Acknowledge) Width
150
125
75
65
ns
40
TdRDA(DR)
RD ↓ (Acknowledge) to Read
Data Valid Delay
41
TsIEI(RDA)
IEI to RD ↓ (Acknowledge) Setup
Time
95
80
50
45
ns
42
ThIEI(RDA)
IEI to RD ↑ (Acknowledge) Hold
Time
0
0
0
0
ns
43
TdIEI(IEO)
IEI to IEO Delay Time
95
80
44
TdPC(IEO)
PCLK ↑ to IEO Delay
200
175
80
70
ns
45
TdRDA(INT)
RD ↓ to INT Inactive Delay (Note 2)
450
320
200
180
ns
46
TdRD(WRQ)
RD ↑ to WR ↓ Delay for No Reset
15
15
10
10
ns
47
TdWRQ(RD)
WR ↑ to RD ↓ Delay for No Reset
15
15
10
10
ns
48
TwRES
WR and RD Coincident Low for
Reset
150
100
75
65
ns
49
Trc
Valid Access Recovery Time
(Note 1)
3.5
3.5
3.5
3.5
TcPc
125
35
0
100
Max Unit
27
150
160
Max
20 MHz
Industrial Only
75
35
0
140
90
65
20
0
120
ns
ns
20
0
ns
ns
4TcPc ns
65
ns
NA
NA
ns
175
160
70
60
45
40
ns
ns
ns
Notes:
1 Parameter applies only between transactions involving the ESCC, if WR/RD falling edge is synchronized to PCLK
falling edge, then TrC = 3TcPc.
2. Open-drain output, measured with open-drain test load.
3. Parameter is system dependent. For any SCC in the daisy chain, TdIAi(RD) must be greater than the sum of DdPC(IEO)
for the highest priority device in the daisy chain, TsIEI(RDA) for the SCC, and TdIEI(IEO) for each device separating
them in the daisy chain.
4. Parameter applies to Enhanced Request mode only.
14
Am85C30
AMENDMENT
AMD
Am85C30 HARDWARE RESET
IN SOFTWARE
In the absence of a hardware logic or a Power-On-Reset
mechanism, the following procedure should be used to
ensure that the ESCC is properly reset.
1. Power Up
2. Read RR0
(Dummy Read)
3. Read RR1
(Dummy Read)
4. Write a C0h to WR9
(Hardware Reset)
5. Read RR0
(Should expect binary
01XXX100 = typically
‘44h’)
6. Read RR1
(Should expect binary
0X000110 = typically
‘06h’)
Note: For hardware reset only steps 1 through 4 are
needed; steps 5 through 8 are mentioned simply for
confirmation. Also, this procedure is applicable to only
the first time hardware reset. Any subsequent chip
reset can be achieved by simply writing a ‘C0’
to WR9.
For further information refer to the Technical Manual
PID # 07513D.
7. Write ‘a value’ to Write Register 2
8. Read RR2
(Should get ‘a value’)
If RR2 = WR2, in steps 7 and 8, then the ESCC is properly reset.
Am85C30
15
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