DATASHEET

HS-82C37ARH
TM
Data Sheet
Radiation Hardened CMOS High
Performance Programmable DMA
Controller
The Intersil HS-82C37ARH is an enhanced, radiation
hardened CMOS version of the industry standard 8237A
Direct Memory Access (DMA) controller, fabricated using the
Intersil hardened field, self-aligned silicon gate CMOS
process. The HS-82C37ARH offers increased functionality,
improved performance, and dramatically reduced power
consumption for the radiation environment. The high speed,
radiation hardness, and industry standard configuration of
the HS-82C37ARH make it compatible with radiation
hardened microprocessors such as the HS-80C85RH and
the HS-80C86RH.
August 2000
File Number
3042.2
Features
• Electrically Screened to SMD # 5962-95821
• QML Qualified per MIL-PRF-38535 Requirements
• Radiation Performance
- Total Dose. . . . . . . . . . . . . . . . . . . . . 100 krad(Si) (Max)
- Transient Upset . . . . . . . . . . . . . . . . . . . . .>108 rad(Si)/s
- Latch Up Free EPI-CMOS
• Low Power Consumption
- IDDSB. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50µA (Max)
- IDDOP . . . . . . . . . . . . . . . . . . . . . . . 4.0mA/MHz (Max)
• Pin Compatible with NMOS 8237A and the Intersil
82C37A
The HS-82C37ARH can improve system performance by
allowing external devices to transfer data directly to or from
system memory. Memory-to-memory transfer capability is
also provided, along with a memory block initialization
feature. DMA requests may be generated by either hardware
or software, and each channel is independently
programmable with a variety of features for flexible
operation.
• High Speed Data Transfers Up To 2.5MBPS With 5MHz
Clock
Static CMOS circuit design insures low operating power and
allows gated clock operation for an even further reduction of
power. Multimode programmability allows the user to select
from three basic types of DMA services, and reconfiguration
under program control is possible even with the clock to the
controller stopped. Each channel has a full 64K address and
word count range, and may be programmed to autoinitialize
these registers following DMA termination (end of process).
The Intersil hardened field CMOS process results in
performance equal to or greater than existing radiation
resistant products at a fraction of the power.
• Hardened Field, Self-Aligned, Junction Isolated CMOS
Process
Specifications for Rad Hard QML devices are controlled
by the Defense Supply Center in Columbus (DSCC). The
SMD numbers listed here must be used when ordering.
Detailed Electrical Specifications for these devices are
contained in SMD 5962-95821. A “hot-link” is provided
on our homepage for downloading.
www.intersil.com/spacedefense/space.asp
1
• Four Independent Maskable Channels with
Autoinitialization Capability
• Expandable to Any Number of Channels
• Memory-to-Memory Transfer Capability
• CMOS Compatible
• Single 5V Supply
• Military Temperature Range . . . . . . . . . . . -55oC to 125oC
Ordering Information
ORDERING NUMBER
INTERNAL
MKT. NUMBER
TEMP. RANGE
(oC)
5962R9582101QQC
HS1-82C37ARH-8
-55 to 125
5962R9582101QXC
HS9-82C37ARH-8
-55 to 125
5962R9582101VQC
HS1-82C37ARH-Q
-55 to 125
5962R9582101VXC
HS9-82C37ARH-Q
-55 to 125
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 321-724-7143 | Intersil and Design is a trademark of Intersil Corporation. | Copyright © Intersil Corporation 2000
HS-82C37ARH
Pinouts
40 LEAD CERAMIC DUAL-IN-LINE METAL SEAL PACKAGE
(SBDIP) MIL-STD-1835 CDIP2-T40
TOP VIEW
IOR
1
40 A7
IOW
2
39 A6
MEMR
3
38 A5
MEMW
4
37 A4
NC
42 LEAD CERAMIC METAL SEAL FLATPACK PACKAGE
(FLATPACK) INTERSIL OUTLINE K42.A
TOP VIEW
IOR
IOW
MEMR
MEMW
1
2
3
4
42
41
40
39
NC
READY
5
6
38
37
7
8
36
35
A7
A6
A5
A4
EOP
5
36 EOP
READY
6
35 A3
HLDA
7
34 A2
ADSTB
8
33 A1
HLDA
ADSTB
AEN
9
32 A0
AEN
9
34
A1
A0
HRQ
10
31 VDD
CS
11
30 DB0
HRQ
CS
10
11
33
32
VDD
DB0
CLK
12
29 DB1
RESET 13
28 DB2
27 DB3
12
13
14
15
31
30
29
28
DB1
DB2
DB3
DACK2 14
CLK
RESET
DACK2
DACK3
DACK3 15
26 DB4
NC
16
27
17
18
19
20
26
25
24
23
NC
DACK0
21
22
DREQ3 16
25
DACK0
DREQ2 17
24
DACK1
DREQ1 18
23 DB5
DREQ3
DREQ2
DREQ1
DREQ0
DREQ0 19
22 DB6
GND
20
21 DB7
(GND)
VSS
A3
A2
DB4
DACK1
DB5
DB6
DB7
Functional Diagram
DECREMENTOR
EOP
TEMP WORD
COUNT REG (16)
RESET
CS
A0-A3
INC DECREMENTOR
I/O BUFFER
TEMP ADDRESS
REG (16)
16-BIT BUS
16-BIT BUS
READY
OUTPUT
BUFFER
READ BUFFER
BASE
WORD
COUNT
(16)
TIMING
AND
CONTROL
AEN
ADSTB
BASE
ADDRESS
(16)
MEMR
BASE
ADDRESS
(16)
BASE
WORD
COUNT
(16)
MEMW
A8-A15
CLOCK
A4-A7
COMMAND
CONTROL
IOR
IOW
WRITE
BUFFER
DREQ0DREQ3
HLDA
HDQ
DACK0DACK3
READ
BUFFER
D0-D1
DB0-DB7
4
4
PRIORITY
ENCODER
AND
ROTATING
PRIORITY
LOGIC
COMMAND (8)
I/O BUFFER
INTERNAL DATA BUS
MASK (4)
REQUEST (4)
2
MODE
(4 x 6)
STATUS (8)
TEMPORARY
(8)
HS-82C37ARH
Pin Descriptions
SYMBOL
PIN
NUMBER
VDD
31
VDD: is the +5V power supply pin. A 0.1µF capacitor between pins 31 and 20 is recommended for
decoupling.
GND
20
Ground
CLK
12
I
CLOCK INPUT: The Clock Input is used to generate the timing signals which control HS-82C37ARH
operations. This input may be driven from DC to 5MHz and may be stopped in either high or low state for
standby operation.
CS
11
I
CHIP SELECT: Chip Select is an active low input used to enable the controller onto the data bus for CPU
communications.
RESET
13
I
RESET: This is an active high input which clears the Command, Status, Request and Temporary Registers,
the First/Last Flip-Flop, and the Mode Register Counter. The Mask Register is Set to ignore requests.
Following a Reset, the controller is in an idle cycle.
READY
6
I
READY: This signal can be sued to extend the memory read and write pulses from the HS-82C37ARH to
accommodate slow memories or I/O devices. Ready must not make transitions during its specified set-up and
hold times. Ready is ignored in Verify Transfer mode.
HLDA
7
I
HOLD ACKNOWLEDGE: The active high Hold Acknowledge from the CPU indicates that is has relinquished
control of the system busses.
DREQ0DREQ3
16-19
I
DMA REQUEST: The DMA Request (DREQ) lines are individual asynchronous channel request inputs used
by peripheral circuits to obtain DMA service. In Fixed Priority, DREQ0 has the highest priority and DREQ3
has the lowest priority. A request is generated by activating the DREQ line of a channel. DACK will
acknowledge the recognition of DREQ signal. Polarity of DREQ is programmable. Reset initializes these lines
to active. DREQ will not be recognized while the clock is stopped. Unused DREQ inputs should be pulled
High or Low (inactive) and the corresponding mask bit set.
DB0-DB7
21-23
26-30
I/O
DATA BUS: The Data Bus lines are bidirectional three-state signals connected to the system data bus. The
outputs are enabled in the Program Condition during the I/O Read to output the contents of a register to the
CPU. The outputs are disabled and the inputs are read during an I/O Write cycle when the CPU is
programming the HS-82C37ARH Control Registers. During DMA cycles, the most significant 8 bits of the
address are output onto the data bus to be strobed into an external latch by ADSTB. In Memory-to-Memory
operations, data from the memory enters the HS-82C37ARH on the data bus during the read-from-memory
transfer, then during the write-to-memory transfer, the data bus outputs write the data into the new memory
location.
IOR
1
I/O
I/O READ: I/O Read is a bidirectional active low three-state line. In the Idle cycle, it is an input control signal
used by the CPU to read the internal registers. In the Active cycle, it is an output control signal used by the
HS-82C37ARH to access data from a peripheral during a DMA Write transfer.
IOW
2
I/O
I/O WRITE: I/O Write is a bidirectional active low three-state line. In the Idle cycle, it is an input control signal
used by the CPU to load information into the HS-82C37ARH. In the Active cycle, it is an output control signal
used by the HS-82C37ARH to load data to the peripheral during a DMA Read transfer.
EOP
36
I/O
END OF PROCESS: End of Process (EOP) is an active low bidirectional signal. Information concerning the
completion of DMA services is available at the bidirectional EOP pin.
The HS-82C37ARH allows an external signal to terminate an active DMA service by pulling the EOP pin low.
A pulse is generated by the HS-82C37ARH when terminal count (TC) for any channel is reached, except for
channel 0 in Memory-to-Memory mode. During Memory-to-Memory transfers, EOP will be output when the
TC for channel 1 occurs.
The EOP pin is driven by an open drain transistor on-chip, and requires an external pull-up resistor.
When an EOP pulse occurs, whether internally or externally generated, the HS-82C37ARH will terminate the
service, and if Autoinitialize is enabled, the base registers will be written to the current registers of that
channel. The mask bit and TC bit in the Status Register will be set for the currently active channel by EOP
unless the channel is programmed for Autoinitialize. In that case, the mask bit remains clear.
A0-A3
32-35
I/O
Address: The four least significant address lines are bidirectional three-state signals. In the Idle cycle, they
are inputs and are used by the HS-80C86RH to address the internal registers to be loaded or read. In the
Active cycle, they are outputs and provide the lower 4 bits of the output address.
A4-A7
37-40
O
Address: The four most significant address lines are three-state outputs and provide 4 bits of address. These
lines are enabled only during the Active cycle.
TYPE
3
DESCRIPTION
HS-82C37ARH
Pin Descriptions (Continued)
SYMBOL
PIN
NUMBER
TYPE
DESCRIPTION
HRQ
10
O
Hold Request: The Hold Request (HRQ) output is used to request control of the system bus. When a DREQ
occurs and the corresponding mask bit is clear, or a software DMA request is made, the HS-82C37ARH
issues HRQ. The HLDA signal then informs the controller when access to the system busses is permitted.
For stand-alone operation where the HS-82C37ARH always controls the busses, HRQ may be tied to HLDA.
This will result in one S0 state before the transfer.
DACK0DACK3
14,15, 24,
25
O
DMA Acknowledge: DMA acknowledge is used to notify the individual peripherals when one has been
granted a DMA cycle. The sense of these lines is programmable. Reset initializes them to active low.
AEN
9
O
Address Enable: Address Enable enables the 8-bit latch containing the upper 8 address bits onto the system
address bus. AEN can also be used to disable other system bus drivers during DMA transfers. AEN is active
HIGH.
ADSTB
8
O
Address Strobe: This is an active high signal used to control latching of the upper address byte. It will drive
directly the strobe input of external transparent octal latches, such as the 82C82. During block operations,
ADSTB will only be issued when the upper address byte must be updated, thus speeding operation through
elimination of S1 states. (See Note 2).
MEMR
3
O
Memory Read: The Memory Read signal is an active low three-state output used to access data from the
selected memory location during a DMA Read or a Memory-to-Memory transfer.
MEMW
4
O
Memory Write: The Memory Write is an active low three-state output used to write data to the selected
memory location during a DMA Write or a Memory-to-Memory transfer.
NC
5
No connect. Pin 5 is open and should not be tested for continuity.
AC Test Circuit
AC Testing Input, Output Waveforms
V1
VOH
VDD -1.5V
1.5V
INPUT
R1
VIL -0.4V
OUTPUT FROM
DEVICE UNDER TEST
OUTPUT
VOL
TEST POINT
C1†
Z
VOL
TEST CONDITION DEFINITION TABLE
V1
R1
C1
All Output Except EOP
1.7V
510Ω
100pF
EOP
VDD
1.6kΩ
50pF
4
VOH
2.0V
0.8V
†Includes Stray and Jig Capacitance
PINS
OUTPUT
L OR H
L OR H
VOH
VOH - 0.45V
0.45
Z
HS-82C37ARH
Waveforms
CS
TIWHAX
TIWLIWH
IOW
TAVIWL
A0-A3
TIWHAX
INPUT VALID
TIWHDX
TDVIWH
DB0-DB7
INPUT VALID
FIGURE 1. SLAVE MODE TIMING
NOTE: Host system must allow at least TCLCL as recovery time between successive write accesses.
CS
A0-A3
ADDRESS MUST BE VALID
TAVIRL
TIRHAX
TIRLIRH
IOR
TIRLDV
TIRHDZ
DB0-DB7
DATA OUT VALID
FIGURE 2. SLAVE MODE READ
NOTE: Host system must allow at least TCLCL as recovery time between successive write accesses.
S2
S3
SW
SW
S4
CLK
TCHRH
TCHRWL
READ†
TCHRWL
TCHRWL
WRITE†
EXTENDED
WRITE
TCLRYX
TRYVCL
TCHWH
TCLRYX
TRYVCL
READY
FIGURE 3. READY
†READ refers to both IOR and MEMR outputs. WRITE refers to both IOW and MEMW outputs.
5
HS-82C37ARH
Waveforms
SI
(Continued)
SI
S0
S1
S0
S2
S3
S4
S2
S3
S4
S1
SI
SI
CLK
TDQVCL
TDQVCL
TCLCL
TCLCH
DREQ
TCHRQV
TCHCL
TCHRQV
HRQ
TRAVCH
HLDA
TCLAEH
AEN
TCHAEL
TCLSL
TCLSH
TSHSL
TEPLCL
ADSTB
TDVSL
DB0-DB7
TCLDAV
TSLDZ
TCHDV
A8-A15
TCHAV
TCHAV
A0-A7
ADDRESS VALID
TWHAZ
ADDRESS VALID
TCLDAV
TRHAX
TCHRH
DACK
TCHAZ
TWHAX
TCHDZ
TRHAZ
TCHRWL
TCHRH
TCHRWV
TCHRWL
TWHRH
TCHRWZ
TRLRH1
READ†
TCHWH
TCHRWL
TCHWH
TWLWH2
WRITE†
TWLWH1
INT EOP
TCHRWL
TCHIPH
(FOR EXTENDED WRITE)
TEPLEPH
TCHIPL
EXT EOP
FIGURE 4. DMA TRANSFER
†READ refers to both IOR and MEMR outputs. WRITE refers to both IOW and MEMW outputs.
6
HS-82C37ARH
Waveforms
(Continued)
S0
S11
S12
S13
S14
S21
S22
S23
S24
SI
CLK
TCLSH
TCLSL
TCLSH
TCLSL
ADSTB
TSLDZ
TCHAV
TSLDZ
TCHAV
A0 - A7
ADDRESS VALID
TCHAZ
ADDRESS VALID
TCHDZ
TCHDV
DB0 - DB7
IN
A8 - A15
TCHRWL
A8 - A15
TCHDV
TCHRH
TDVMWH
TMRHDX
MEMR
OUT
TMWHDZ
TDVMRH
TCHWH
TCHRVW
TCHRWL
TCHRWL
TCHRWZ
EXTENDED
WRITE
TCHIPL
INT EOP
TCHIPH
TEPLCL
TEPLEPH
FIGURE 5. MEMORY-TO-MEMORY TRANSFER
TPHRSL
VDD
TRSHRSL
RESET
TRSLIRWL
IOR OR IOW
FIGURE 6. RESET
7
HS-82C37ARH
Waveforms
(Continued)
S2
S4
S2
S4
CLK
TCHAV
TCHAV
VALID
A0 - A7
VALID
TCHRH
TCHRWL
TCHRWL
TCHRH
TRLRH2
READ†
TCHWH
TCHWH
WRITE†
TCLRYX
TRYVCL
TCLRYX
TRYVCL
READY
FIGURE 7. COMPRESSED TRANSFER
†READ refers to both IOR and MEMR outputs. WRITE refers to both IOW and MEMW outputs.
8
HS-82C37ARH
Burn-In Circuits
HS-82C37ARH 40 LEAD SBDIP
HS-82C37ARH 40 LEAD SBDIP
VDD
1
40
2
39
3
38
4
37
5
36
6
35
7
34
8
33
9
32
10
31
11
30
F0
12
29
F1
13
28
14
27
15
26
16
25
17
24
18
23
19
22
20
21
VDD
F0
1
40
LOAD
2
39
LOAD
LOAD
3
38
LOAD
LOAD
4
37
LOAD
NC
5
36
6
35
7
34
LOAD
8
33
LOAD
9
32
LOAD
10
31
11
30
12
29
13
28
F5
14
27
F4
15
26
F3
F1
16
25
LOAD
F2
17
24
LOAD
F3
18
23
F2
F4
19
22
F1
20
21
F0
F0
F5
LOAD
LOAD
VDD
2.7kΩ
STATIC CONFIGURATION
NOTES:
LOAD
1. VDD = +6.0V ±5%
2.7kΩ
Part is Static Sensitive
2. TA = 125oC MinimumVoltage Must be Ramped
3. Resistors:
R1 = 10kΩ ±10% (Pins 6, 7, 11-13, 17 - 20)
R2 = 2.7kΩ ±5% (Pins 1, 2, 21-23, 24, 28-32, 34-39)
F0
F1
START-UP TIMING
NOTES:
DYNAMIC CONFIGURATION
NOTES:
4. F0 is 50% duty cycle square wave pulse burst.
10. VDD = 6.5V ±5% (Burn-In)
5. 1.0kHz ≤ F0 ≤ 100kHzF0 is left High after pulse burst
11. VDD = 6.0V ±5% (Life Test)
6. 10 cycles ≤ F0 Pulse Burst ≤ 1.0s
12. TA = 125oC Minimum
7. F1 = Single pulse with width equal to 2 cycles of F0
13. Part is Static Sensitive, Voltage Must be Ramped
8. F1 is left Low after pulse burst
14. Resistors:
R1 = 10kΩ ±10% (Pins 6, 7, 11-13, 17 - 20)
R2 = 2.7kΩ ±10% (Pins 1, 2, 22-24, 28-32, 34-37, and LOADS)
9. F1 pulse occurs after start of F0 and ends before F0.
Input levels: 0.9VDD ≤ VIH ≤ VDD, -0.3V ≤ VIL ≤ 0.7V
9
HS-82C37ARH
Burn-In Circuits
(Continued)
HS-82C37ARH 42 LEAD CERAMIC FLATPACK
HS-82C37ARH 42 LEAD CERAMIC FLATPACK
VDD
1
42
1
42
LOAD
2
41
2
41
LOAD
3
40
LOAD
3
40
LOAD
4
39
LOAD
4
39
LOAD
5
38
OPEN
5
38
6
37
6
37
7
36
7
36
8
35
LOAD
8
35
9
34
LOAD
9
34
LOAD
10
33
11
32
F0
10
33
11
32
F0
12
31
F0
12
31
F1
13
30
F5
13
30
F5
29
F4
VDD
14
29
LOAD
14
15
28
LOAD
15
28
16
27
OPEN
16
27
OPEN
17
26
F1
17
26
LOAD
18
25
F2
18
25
LOAD
19
24
F3
19
24
F2
20
23
F4
20
23
F1
21
22
21
22
F0
F3
VDD
STATIC CONFIGURATION
2.7kΩ
NOTES:
15. VDD = +6.0V ±5%Part is Static Sensitive
LOAD
2.7kΩ
16. TA = 125oC MinimumVoltage Must be Ramped
17. Resistors:
R1 = 10kΩ ±10% (Pins 6, 7, 11-13, 16-19)
R2 = 2.7kΩ ±5% (Pins 1, 2, 21-23, 26-30, 32-36)
F0
F1
START-UP TIMING
NOTES:
DYNAMIC CONFIGURATION
NOTES:
18. F0 is 50% duty cycle square wave pulse burst.
24. VDD = 6.5V ±5% (Burn-In)
19. 1.0kHz ≤ F0 ≤ 100kHzF0 is left High after pulse burst
25. VDD = 6.0V ±5% (Life Test)
20. 10 cycles ≤ F0 Pulse Burst ≤ 1.0s
26. TA = 125oC Minimum
21. F1 = Single pulse with width equal to 2 cycles of F0
27. Part is Static Sensitive, Voltage Must be Ramped
22. F1 is left Low after pulse burst
28. Resistors:
R1 = 10kΩ ±10% (Pins 6, 7, 11-13, 16-19)
R2 = 2.7kΩ ±10% (Pins 1, 2, 21-23, 26-30, 32-36, and LOADS)
23. F1 pulse occurs after start of F0 and ends before F0.
Input levels: 0.9VDD ≤ VIH ≤ VDD, -0.3V ≤ VIL ≤ 0.7V
10
HS-82C37ARH
Irradiation Circuit
R
1
40
LOAD
2
39
LOAD
LOAD
3
38
LOAD
LOAD
4
37
LOAD
R
5
36
6
35
R
LOAD
VCC
2.7kΩ
NC
R
OUT
R
2.7kΩ
R
R
7
34
LOAD
8
33
LOAD
9
32
LOAD
R
10
31
11
30
LOAD 2
12
29
LOAD 2
13
28
LOAD 2
LOAD 2
14
27
LOAD 2
LOAD 2
R
15
26
LOAD 2
16
25
LOAD 2
17
24
LOAD 2
18
23
LOAD 2
19
22
LOAD 2
20
21
LOAD 2
VSS
R
R
R
TOGGLE
CLOCK
RESET
TOGGLE
R
R
R
R
VSS
VCC
5.5V
LOAD 2
OUT
2.7kΩ
VSS
NOTES:
29. R = 47kΩ
30. Pins with Load: 3, 4, 8, 9, 10, 37-40
Pins with Load2: 14, 15, 21-30
Pins Brought Out: 12 (Clock), 13 (Reset)
31. VDD = 5.5V ±0.5V
Functional Description
The HS-82C37ARH Direct Memory Access Controller is
designed to improve the data transfer rate in systems which
must transfer data from an I/O device to memory, or move a
block of memory to an I/O device. It will also perform
memory-to-memory block moves, or fill a block of memory
with data from a single location. Operating modes are
provided to handle single byte transfers as well as
discontinuous data streams, which allows the
HS-82C37ARH to control data movement with software
transparency.
The DMA controller is a state-driven address and control
signal generator, which permits data to be transferred
directly from an I/O device to memory or vice versa without
ever being stored in a temporary register. This can greatly
increase the data transfer rate for sequential operations,
compared with processor moves or repeated string
instructions. Memory-to-Memory operations require
temporary internal storage of the data byte between
11
generation of the source and destination addresses, so
Memory-to-Memory transfers take place at less than half the
rate of I/O operations, but still much faster than with central
processor techniques. The maximum data transfer rate
obtainable with the HS-82C37ARH is approximately
2.5 Mbytes/second, for an I/O operation using the compressed
timing option and 5MHz clock.
The block diagram of the HS-82C37ARH is shown on page
2. The Timing and Control Block, Priority Block, and internal
registers are the main components. Figure 8 lists the name
and size of the internal registers. The Timing and Control
Block derives internal timing from the CLOCK input, and
generates external control signals. The Priority Encoder
Block resolves priority contention between DMA channels
requesting service simultaneously.
HS-82C37ARH
NAME
SIZE
NUMBER
Base Address Registers
16 bits
4
Base Word Count Registers
16 bits
4
Current Address Registers
16 bits
4
Current Word Count Registers
16 bits
4
Temporary Address Register
16 bits
1
Temporary Word Count Register
16 bits
1
Status Register
8 bits
1
Command Register
8 bits
1
Temporary Register
8 bits
1
Mode Registers
6 bits
4
Mask Registers
4 bits
1
Request Register
4 bits
1
FIGURE 8. HS-82C37ARH INTERNAL REGISTERS
DMA Operation
In a system, the HS-82C37ARH address and control outputs
and data bus pins are basically connected in parallel with the
system busses. An external latch is required for the upper
address byte. While inactive, the controller’s outputs are in a
high impedance state. When activated by a DMA request
and bus control is relinquished by the host, the
HS-82C37ARH drives the busses and generates the control
signals to perform the data transfer. The operation
performed by activating one of the four DMA request inputs
has previously been programmed into the controller via the
Command, Mode, Address, and Word Count Registers.
For example, if a block of data is to be transferred from RAM
to an I/O device, the starting address of the data is loaded
into the HS-82C37ARH Current and Base Address
Registers for a particular channel, and the length of the block
is loaded into that channel’s Word Count Register. The
corresponding Mode Register is programmed for a
Memory-to-I/O operation (read transfer), and various options
are selected by the Command Register and other Mode
Register bits. The channel’s mask bit is cleared to enable
recognition of a DMA request (DREQ). The DREQ can either
be a hardware signal or a software command.
Once initiated, the block DMA transfer will proceed as the
controller outputs the data address, simultaneous MEMR
and IOW pulses, and selects an I/O device via the DMA
acknowledge (DACK) outputs. The data byte flows directly
from the RAM to the I/O device. After each byte is
transferred, the address is automatically incremented (or
decremented) and the word count is decremented. The
operation is then repeated for the next byte. The controller
stops transferring data when the Word Count Register
underflows, or an external EOP is applied.
To further understand HS-82C37ARH operation, the states
generated by each clock cycle must be considered. The
12
DMA controller operates in two major cycles, Active and Idle.
After being programmed, the controller is normally Idle until
a DMA request occurs on an unmasked channel, or a
software request is given. The HS-82C37ARH will then
request control of the system busses and enter the Active
cycle. The Active cycle is composed of several internal
states, depending on what options have been selected and
what type of operation has been requested.
The HS-82C37ARH can assume seven separate states,
each composed of one full clock period. State I (SI) is the
Idle state. It is entered when the HS-82C37ARH has no valid
DMA requests pending, at the end of a transfer sequence, or
when a Reset or Master Clear has occurred. While in SI, the
DMA controller is inactive but may be in the Program
Condition (being programmed by the processor.)
State 0 (S0) is the first state of a DMA service. The
HS-82C37ARH has requested a hold but the processor has
not yet returned an acknowledge. The HS-82C37ARH may
still be programmed until it has received HLDA from the
CPU. An acknowledge from the CPU will signal that DMA
transfers may begin. S1, S2, S3 and S4 are the working
states of the DMA service. If more time is needed to
complete a transfer than is available with normal timing, wait
states (SW) can be inserted between S2 or S3 and S4 by
the use of the Ready line on the HS-82C37ARH.
Note that the data is transferred directly from the I/O device
to memory (or vice versa) with IOR and MEMW (or MEMR
and IOW) being active at the same time. The data is not read
into or driven out of the HS-82C37ARH in I/O-to-memory or
memory-to-I/O DMA transfers.
Memory-to-Memory transfers require a read-from and a
write-to-memory to complete each transfer. The states,
which resemble the normal working states, use two-digit
numbers for identification. Eight states are required for a
single transfer. The first four states (S11, S12, S13, S14) are
used for the read-from-memory half and the last four states
(S21, S22, S23, S24) for the write-to-memory half of the
transfer.
Idle Cycle
When no channel is requesting service, the HS-82C37ARH
will enter the Idle cycle and perform “SI” states. In this cycle,
the HS-82C37ARH will sample the DREQ lines on the falling
edge of every clock cycle to determine if any channel is
requesting a DMA service.
Note that for standby operation where the clock has been
stopped, DMA requests will be ignored. The device will
respond to CS (chip select), in case of an attempt by the
microprocessor to write or read the internal registers of the
HS-82C37ARH. When CS is low and HLDA is low, the
HS-82C37ARH enters the Program Condition. The CPU can
now establish, change or inspect the internal definition of the
part by reading from or writing to the internal registers.
HS-82C37ARH
The HS-82C37ARH may be programmed with the clock
stopped, provided that HLDA is low and at least one rising
clock edge has occurred after HLDA was driven low, so the
controller is in an SI state. Address lines A0-A3 are inputs to
the device and select which registers will be read or written.
The IOR and IOW lines are used to select and time the read
or write operations. Due to the number and size of the internal
registers, an internal flip-flop is used to generate an additional
bit of address. The bit is used to determine the upper or lower
byte of the 16-bit Address and Word Count Registers. The
flip-flop is reset by Master Clear or Reset. Separate software
commands can also set or reset this flip-flop.
Special software commands can be executed by the
HS-82C37ARH in the Program Condition. These commands
are decoded as sets of addresses with CS, IOR, and IOW.
The commands do not make use of the data bus.
Instructions include Set and Clear First/Last Flip-Flop,
Master Clear, Clear Mode Register Counter, and Clear Mask
Register.
Active Cycle
When the HS-82C37ARH is in the Idle cycle, and a software
request or an unmasked channel requests a DMA service,
the device will output an HRQ to the microprocessor and
enter the Active cycle. It is in this cycle that the DMA service
will take place, in one of four modes:
Single Transfer Mode - In Single Transfer mode, the device
is programmed to make one transfer only. The word count
will be decremented and the address decremented or
incremented following each transfer. When the word count
“rolls over” from zero to FFFFH, a terminal count (TC) bit in
the Status Register is set, an EOP pulse is generated, and
the channel will Autoinitialize if this option has been
selected. If not programmed to Autoinitialize, the mask bit
will be set, along with the TC bit and EOP pulse.
DREQ must be held active until DACK becomes active. If
DREQ is held active throughout the single transfer (there-by
triggering a second transfer), HRQ will still go inactive and
release the bus to the system. Then it will again go active
and, upon receipt of a new HLDA, another single transfer will
be performed, unless a higher priority channel takes over. In
HS-80C85RH or HS-80C86RH systems, this will ensure one
full machine cycle execution between DMA transfers. Details
of timing between the HS-82C37ARH and other bus control
protocols will depend upon the characteristics of the
microprocessor involved.
Block Transfer Mode - In Block Transfer Mode, the device is
activated by DREQ or software request and continues
making transfers during the service until a TC, caused by
word count going to FFFFH, or an external End of Process
(EOP) is encountered. DREQ need only beheld active until
DACK becomes active. Again, an Autoinitialization will occur
at the end of the service if the channel has been
programmed for that option.
13
Demand Transfer Mode - In Demand Transfer Mode the
device continues making transfers until a TC or external
EOP is encountered, or until DREQ goes inactive. Thus,
transfers may continue until the I/O device has exhaust edits
data capacity. After the I/O device has had a chance to catch
up, the DMA service is reestablished by means of a DREQ.
During the time between services when the micro-processor
is allowed to operate, the intermediate values of address and
word count are stored in the HS-82C37ARH Current
Address and Current Word Count Registers. Higher priority
channels may intervene in the demand process, once DREQ
has gone inactive. Only an EOP can cause an
Autoinitialization at the end of the service. EOP is generated
either by TC or by an external signal.
Cascade Mode - This mode is used to cascade more than
one HS-82C37ARH for simple system expansion. The HRQ
and HLDA signals from the additional HS-82C37ARH are
connected to the DREQ and DACK signals respectively of a
channel for the initial HS-82C37ARH. This allows the DMA
requests of the additional device to propagate through the
priority network circuitry of the preceding device. The priority
chain is preserved and the new device must wait for its turn
to acknowledge requests. Since the cascade channel of the
initial HS-82C37ARH is used only for prioritizing the
additional device, it does not output an address or control
signals of its own so that there is no conflict with the
cascaded device. The HS-82C37ARH will respond to DREQ
and generate DACK but all other outputs except HRQ will be
disabled. An external EOP will be ignored by the initial
device, but will have the usual effect on the added device.
Figure 9 shows two additional devices cascaded with an
initial device using two of the previous channels. This forms
a two-level DMA system. More HS-82C37ARHs could be
added at the second level by using the remaining channels
of the first level. Additional devices can also be added by
cascading into the channels of the second level devices,
forming a third level.
HS-82C37ARH
2ND LEVEL
HS-80C86RH
MICROPROCESSOR
HS-82C37ARH
1ST LEVEL
HRQ
HLDA
DREQ
DACK
HRQ
HLDA
HS-82C37ARH
DREQ
DACK
HRQ
HLDA
INITIAL DEVICE
HS-82C37ARH
ADDITIONAL
DEVICES
FIGURE 9. CASCADED HS-82C37ARHs
When programming cascaded controllers, start with the first
level (closest to the microprocessor). After RESET, the
DACK outputs are programmed to be active low and are held
in the high state. If they are used to drive HLDA directly, the
second level device(s) cannot be programmed until DACK
polarity is selected as active high on the initial device. Also,
the initial device’s mask bits function normally on cascaded
channels, so they may be used to inhibit second-level services.
Transfer Types
Each of the three active transfer modes can perform three
different types of transfers. These are Read, Write and Verify.
Write transfers move data from an I/O device to the memory
by activating MEMW and IOR. Read transfers move data from
memory to an I/O device by activating MEMR and IOW.
Verify transfers are pseudo-transfers. The HS-82C37ARH
operates as in Read or Write transfers generating addresses
and responding to EOP, etc., however the memory and I/O
control lines all remain inactive. Verify mode is not permitted
for Memory-to-Memory operation. Ready is ignored during
Verify transfers.
Autoinitialize - By programming a bit in the Mode Register,
a channel may be set up as an Autoinitialize channel. During
Autoinitialization, the original values of the Current Address
and Current Word Count Registers are automatically
restored from the Base Address and Base Word Count
Registers of that channel following EOP. The base registers
are loaded simultaneously with the current registers by the
microprocessor and remain unchanged throughout the DMA
service. The mask bit is not set when the channel is in
Autoinitialize. Following Autoinitialization, the channel is
ready to perform another DMA service, without CPU
intervention, as soon as a valid DREQ is detected, or software
request made.
14
Memory-to-Memory - To perform block moves of data from
one memory address space to another with minimum of
program effort and time, the HS-82C37ARH includes a
Memory-to-Memory transfer feature. Programming a bit in
the Command Register selects channels 0 and 1 to operate
as Memory-to-Memory transfer channels.
The transfer is initiated by setting the software or hardware
DREQ for channel 0. The HS-82C37ARH requests a DMA
service in the normal manner. After HLDA is true, the device,
using four-state transfers in Block Transfer Mode, reads data
from the memory. The channel 0 Current Address Register is
the source for the address used and is decremented or
incremented in the normal manner. The data byte read from the
memory is stored in the HS-82C37ARH internal Temporary
Register. Another four-state transfer moves the data to memory
using the address in channel 1’s Current Address Register and
incrementing or decrementing it in the normal manner. The
channel 1 Current Word Count Register is decremented.
When the word count of channel 1 goes to FFFFH, a TC is
generated causing an EOP output terminating the service.
Channel 0 word count decrementing to FFFFH will not set
the channel 0 TC bit in the Status Register or generate an
EOP in this mode. It will cause an Autoinitialization of
channel 0, if that option has been selected.
If full Autoinitialization for a Memory-to-Memory operation is
desired, the channel 0 and channel 1 word counts must be
set equal before the transfer begins. Otherwise, if channel 0
underflows before channel 1, it will Autoinitialize and set the
data source address back to the beginning of the block. If the
channel 1 word count underflows before channel 0, the
Memory-to-Memory DMA service will terminate, and
channel 1 will Autoinitialize but channel 0 will not.
In Memory-to-Memory Mode, Channel 0 may be
programmed to retain the same address for all transfers.
This allows a single byte to be written to a block of memory.
This channel 0 address hold feature is selected by bit 1 in
the Command Register.
The HS-82C37ARH will respond to external EOP signals
during Memory-to-Memory transfers, but will only relinquish
the system busses after the transfer is complete (i.e., after
an S24 state). Data comparators in block search schemes
may use this input to terminate the service when a match is
found. The timing of Memory-to-Memory transfers is found in
Figure 5. Memory-to-Memory operations can be detected as
an active AEN with no DACK outputs.
Priority - The HS-82C37ARH has two types of priority
encoding available as software selectable options. The first
is Fixed Priority which fixes the channels in priority order
based upon the descending value of their numbers. The
channel with the lowest priority is 3 followed by 2, 1 and the
highest priority channel, 0. After the recognition of any one
channel for service, the other channels are prevented from
interfering with the service until it is completed.
HS-82C37ARH
The second scheme is Rotating Priority. The last channel to
get service becomes the lowest priority channel with the
others rotating accordingly. The next lower channel from the
channel serviced has highest priority on the following
request: Priority rotates every time control of the system
busses is returned to the processor.
Rotating Priority
1ST
SERVICE
2ND
SERVICE
HIGHEST 0
1
SERVICE
Programming
3RD
SERVICE
2
SERVICE
3
3
REQUEST
0
2
0
1
LOWEST 3
1
2
SERVICE
With Rotating Priority in a single chip DMA system, any
device requesting service is guaranteed to be recognized
after no more than three higher priority services have
occurred. This prevents any one channel from monopolizing
the system.
Regardless of which priority scheme is chosen, priority is
evaluated every time a HLDA is returned to the
HS-82C37ARH.
Compressed Timing - In order to achieve even greater
throughput where system characteristics permit, the
HS-82C37ARH can compress the transfer time to two clock
cycles. From Figure 4 it can be seen that state S3 is used to
extend the access time of the read pulse. By removing state
S3, the read pulse width is made equal to the write pulse
width and a transfer consists only of state S2 to change the
address and state S4 to perform the read/write. S1 states
will still occur when A8-A15 need updating (see Address
Generation). Timing for compressed transfers is found in
Figure 7. EOP will be output in S2 if compressed timing is
selected. Compressed Timing is not allowed for
Memory-to-Memory transfers.
Address Generation - In order to reduce pin count, the
HS-82C37ARH multiplexes the eight higher order address
bits on the data lines. State S1 is used to output the higher
order address bits to an external latch from which they may
be placed on the address bus. The falling edge of Address
Strobe (ADSTB) is used to load these bits from the data
lines to the latch. Address Enable (AEN) is used to enable
the bits onto the address bus through a three-state enable.
The lower order address bits are output by the
HS-82C37ARH directly. Lines A0-A7 should be connected to
the address bus. Figure 4 shows the time relationships
between CLK, AEN, ADSTB, DB0-DB7 and A0-A7.
During Block and Demand Transfer Mode service, which
include multiple transfers, the addresses generated will be
sequential. For many transfers the data held in the external
address latch will remain the same. This data need only
15
change when a carry or borrow from A7 to A8 takes place in
the normal sequence of addresses. To save time and speed
transfers, the HS-82C37ARH executes S1 states only when
updating of A8-A15 in the latch is necessary. This means for
long services, S1 states and Address Strobes may occur
only once every 256 transfers, a savings of 255 clock cycles
for each 256 transfers.
The HS-82C37ARH will accept programming from the host
processor anytime that HLDA is inactive, and at least one
rising clock edge has occurred after HLDA went low. It is the
responsibility of the host to assure that programming and
HLDA are mutually exclusive.
Note that a problem can occur if a DMA request occurs on
an unmasked channel while the HS-82C37ARH is being
programmed. For instance, the CPU may be starting to
reprogram the two byte Address Register of channel 1 when
channel 1 receives a DMA request. If the HS-82C37ARH is
enabled (bit 2 in the command register is 0), and channel 1
is unmasked, a DMA service will occur after only one byte of
the Address Register has been reprogrammed. This
condition can be avoided by disabling the controller (setting
bit 2 in the Command Register) or masking the channel
before programming any of its registers. Once the
programming is complete, the controller can be
enabled/unmasked.
After power-up it is suggested that all internal locations be
loaded with some known value, even if some channels are
unused. This will aid in debugging.
Register Description
Current Address Register - Each channel has a 16-bit
Current Address Register. This register holds the value of
the address used during DMA transfers. The address is
automatically incremented or decremented after each
transfer and the values of the address are stored in the
Current Address Register during the transfer. This register is
written or read by the microprocessor in successive 8-bit
bytes. It may also be reinitialized by an Autoinitialize back to
its original value. Autoinitialize takes place only after an EOP.
In Memory-to-Memory Mode, the channel 0 Current Address
Register can be prevented from incrementing or
decrementing by setting the address hold bit in the
Command Register.
Current Word Register - Each channel has a 16-Bit Current
Word Count Register. This register determines the number
of transfers to be performed. The actual number of transfers
will be one more than the number programmed in the
Current Word Count Register (i.e., programming a count of
100 will result in 101 transfers). The word count is
decremented after each transfer. When the value in the
register goes from zero to FFFFH, a TC will be generated.
This register is loaded or read in successive 8-bit bytes by
HS-82C37ARH
the microprocessor in the Program Condition. Following the
end of a DMA service it may also be reinitialized by an
Autoinitialization back to its original value. Autoinitialization
can occur only when an EOP occurs. If it is not
Autoinitialized, this register will have a count of FFFFH after
TC.
Base Address and Base Word Count Registers - Each
channel has a pair of Base Address and Base Word Count
Registers. These 16-bit registers store the original value of
their associated current registers. During Autoinitialization,
these values are used to restore the current registers to their
original values. The base registers are written
simultaneously with their corresponding current register in
8-bit bytes in the Program Condition by the microprocessor.
These registers cannot be read by the microprocessor.
Mask Register - Each channel has associated with it a
mask bit which can be set to disable an incoming DREQ.
Each mask bit is set when its associated channel produces
an EOP if the channel is not programmed to Autoinitialize.
Each bit of the 4-bit Mask Register may also be set or
cleared separately or simultaneously under soft-ware
control. The entire register is also set by a Reset or Master
Clear. This disables all hardware DMA requests until a clear
Mask Register instruction allows them to occur. The
instruction to separately set or clear the mask bits is similar
in form to that used with the Request Register. Refer to the
following table and Figure 10 for details. When reading the
Mask Register, bits 4-7 will always read as logical ones, and
bits 0-3 will display the mask bits of channel 0-3,
respectively. The 4 bits of the Mask Register may be cleared
simultaneously by using the Clear Mask Register command
(see software commands section).
Mask Register
7
6
5
4
3
2
1
BIT NUMBER
0
DON’T CARE
00
01
10
11
SELECT CHANNEL 0 MASK BIT
SELECT CHANNEL 1 MASK BIT
SELECT CHANNEL 2 MASK BIT
SELECT CHANNEL 3 MASK BIT
0
1
CLEAR MASK BIT
SET MASK BIT
All four bits of the Mask Register may also be written with a
single command.
Mode Register - Each channel has a 6-bit Mode Register
associated with it. When the register is being written to by
the microprocessor in the Program Condition, bits 0 and 1
determine which channel Mode Register is to be written.
When the processor reads a Mode Register, bits 0 and 1 will
both be ones. See the adjacent table and Figure 10 for Mode
Register functions and addresses.
Mode Register
7
6
6
5
4
3
2
1
4
3
2
1
BIT NUMBER
0
00
01
10
11
XX
CHANNEL 0 SELECT
CHANNEL 1 SELECTT
CHANNEL 2 SELECT
CHANNEL 3 SELECT
READBACK
00
01
10
11
XX
VERIFY TRANSFER
WRITE TRANSFER
READ TRANSFER
ILLEGAL
IF BITS 6 AND 7 = 11
0
1
AUTOINITIALIZATION DISABLE
AUTOINITIALIZATION ENABLE
0
1
ADDRESS INCREMENT SELECT
ADDRESS DECREMENT SELECT
00
01
10
11
DEMAND MODE SELECT
SINGLE MODE SELECT
BLOCK MODE SELECT
CASCADE MODE SELECT
Request Register - The HS-82C37ARH can respond to
requests for DMA service which are initiated by software as
well as by a DREQ. Each channel has a request bit
associated with it in the 4-bit Request Register. These are
non-maskable and subject to prioritization by the Priority
Encoder network. Each register bit is set or reset separately
under software control. The entire register is cleared by a
Reset. To set or reset a bit, the software loads the proper
form of the data word. See Figure 10 for register address
coding, and the following table for Request Register format.
A software request for DMA operation can be made in Block
or Single Modes. For Memory-to-Memory transfers, the
software request for channel 0 should be set. When reading
the Request Register, bits 4-7 will always read as ones, and
bits 0-3 will display the request bits of channels 0-3
respectively.
Request Register
7
7
5
6
5
4
3
2
1
BIT NUMBER
0
BIT NUMBER
0
0 CLEAR CHANNEL 0 MASK BIT
1 SET CHANNEL 0 MASK BIT
DON’T CARE,
WRITE ALL
ONES,
READ
0 CLEAR CHANNEL 1 MASK BIT
1 SET CHANNEL 1 MASK BIT
DON’T CARE,
WRITE BITS 4-7
ALL ONES, READ
00
01
10
11
SELECT CHANNEL 0
SELECT CHANNEL 1
SELECT CHANNEL 2
SELECT CHANNEL 3
0
1
RESET REQUEST BIT
SET REQUEST BIT
0 CLEAR CHANNEL 2 MASK BIT
1 SET CHANNEL 2 MASK BIT
0 CLEAR CHANNEL 3 MASK BIT
1 SET CHANNEL 3 MASK BIT
16
Command Register - This 8-bit register controls the
operation of the HS-82C37ARH. It is programmed by the
microprocessor and is cleared by Reset or a Master Clear
HS-82C37ARH
instruction. The adjacent table lists the function of the
command bits. See Figure 10 for Read and Write addresses.
Command Register
7
6
5
4
3
2
1
BIT NUMBER
0
0 MEM-TO-MEM DISABLE
1 MEM-TO-MEM ENABLE
0 CH. 0 ADDR. HOLD DISABLE
1 CH. 0 ADDR. HOLD ENABLE
X IF BIT 0 = 0
These bits are cleared upon Reset, Master Clear, and on
each Status Read. Bits 4-7 are set whenever their
corresponding channel is requesting service, regardless of
the mask bit state. If the mask bits are set, software can poll
the Status Register to determine which channels have
DREQs, and selectively clear a mask bit, thus allowing user
defined service priority. Status bits 4-7 are updated while the
clock is high, and latched on the falling edge. Status Bits 4-7
are cleared upon Reset or Master Clear.
Status Register
0 CONTROLLER ENABLE
1 CONTROLLER DISABLE
7
6
5
4
3
2
1
BIT NUMBER
0
0 NORMAL TIMING
1 COMPRESSED TIMING
X IF BIT 0 = 1
0 FIXED PRIORITY
1 ROTATING PRIORITY
0 LATE WRITE SELECTION
1 EXTENDED WRITE SEL.
X IF BIT 3 = 1
0 DREQ SENSE ACTIVE HIGH
1 DREQ SENSE ACTIVE LOW
1
1
1
1
CHANNEL 0 HAS REACHED TC
CHANNEL 1 HAS REACHED TC
CHANNEL 2 HAS REACHED TC
CHANNEL 3 HAS REACHED TC
1
1
1
1
CHANNEL 0 REQUEST
CHANNEL 1 REQUEST
CHANNEL 2 REQUEST
CHANNEL 3 REQUEST
0 DACK SENSE ACTIVE LOW
1 DACK SENSE ACTIVE HIGH
Status Register - The Status Register contains information
about the present status of the HS-82C37ARH and can be
read by the microprocessor. This information includes which
channels have reached a terminal count and which channels
have pending DMA requests. Bits 0-3 are set every time a
TC is reached by that channel or an external EOP is applied.
OPERATION
Temporary Register - The Temporary Register is used to
hold data during Memory-to-Memory transfers. Following the
completion of the transfer, the last word moved can be read
by the microprocessor by accessing this register. The
Temporary Register always contains the last byte transferred
in the previous Memory-to-Memory operation, unless
cleared by a Reset or Master Clear.
A3
A2
A1
A0
IOR
IOW
Read Status Register
1
0
0
0
0
1
Write Command Register
1
0
0
0
1
0
Read Request Register
1
0
0
1
0
1
Write Request Register
1
0
0
1
1
0
Read Command Register
1
0
1
0
0
1
Write Single Mask Bit
1
0
1
0
1
0
Read Mode Register
1
0
1
1
0
1
Write Mode Register
1
0
1
1
1
0
Set Byte Pointer F/F
1
1
0
0
0
1
Clear Byte Pointer F/F
1
1
0
0
1
0
Read Temporary Register
1
1
0
1
0
1
Master Clear
1
1
0
1
1
0
Clear Mode Reg. Counter
1
1
1
0
0
1
Clear Mask Register
1
1
1
0
1
0
Read All Mask Bits
1
1
1
1
0
1
Write All Mask Bits
1
1
1
1
1
0
FIGURE 10. SOFTWARE COMMAND CODES AND REGISTER CODES
17
HS-82C37ARH
Software Commands
There are special software commands which can be
executed by reading or writing to the HS-82C37ARH. These
commands do not depend on the specific data pattern on the
data bus, but are activated by the I/O operation itself. On
read type commands, the data value is not guaranteed.
These commands are:
Clear First/Last Flip-Flop: This command is executed prior
to writing or reading new address or word count information
to the HS-82C37ARH. This initializes the flip-flop to a known
state so that subsequent accesses to register contents by
the microprocessor will address upper and lower bytes in the
correct sequence.
Set First/Last Flip-Flop: This command will set the flip-flop
to select the high byte first on read and write operations to
Address and Word Count registers.
Master Clear: This software instruction has the same effect
as the hardware Reset. The Command, Status, Request,
and Temporary Registers, and Internal First/Last Flip-Flop
and Mode Register Counter are cleared and the Mask
Register is set. The HS-82C37ARH will enter the Idle cycle.
Clear Mask Register: This command clears the mask bits
of all four channels, enabling them to accept DMA requests.
Clear Mode Register Counter: Since only one address
location is available for reading the Mode Registers, an
internal two-bit counter has been included to select Mode
Registers during read operations. To read the Mode
Registers, first execute the Clear Mode Register Counter
command, then do consecutive reads until the desired
channel is read. Read order is channel 0 first, channel 3 last.
The lower two bits on all Mode Registers will read as ones.
External EOP Operation
The EOP pin is a bidirectional, open drain pin which may be
driven by external signals to terminate DMA operation.
Because EOP is an open drain pin an external pull-up resistor
is required. The value of the external pull-up resistor used
should guarantee a rise time of less than 125ns. It is important
to note that the HS-82C37ARH will not accept external EOP
signals when it is in an SI (Idle)state. The controller must be
active to latch EXT EOP. Once latched, the EXT EOP will be
acted upon during the next S2 state, unless the HS82C37ARH enters an Idle state first. In the latter case the
latched EOP is cleared. External EOP pulses occurring
between active DMA transfers in demand mode will not be
recognized, since the HS-82C37ARH is in an SI state.
18
HS-82C37ARH
SIGNALS
OPERATION
CS
IOR
IOW
A3
A2
A1
A0
INTERNAL
FLIP-FLOP
Base and Current
Address
Write
0
0
1
1
0
0
0
0
0
0
0
0
0
0
0
1
A0-A7
A8-A15
Current Address
Read
0
0
0
0
1
1
0
0
0
0
0
0
0
0
0
1
A0-A7
A8-A15
Base and Current Word
Count
Write
0
0
1
1
0
0
0
0
0
0
0
0
1
1
0
1
W0-W7
W8-W15
Current Word Count
Read
0
0
0
0
1
1
0
0
0
0
0
0
1
1
0
1
W0-W7
W8-W15
Base and Current
Address
Write
0
0
1
1
0
0
0
0
0
0
1
1
0
0
0
1
A0-A7
A8-A15
Current Address
Read
0
0
0
0
1
1
0
0
0
0
1
1
0
0
0
1
A0-A7
A8-A15
Base and Current Word
Count
Write
0
0
1
1
0
0
0
0
0
0
1
1
1
1
0
1
W0-W7
W8-W15
Current Word Count
Read
0
0
0
0
1
1
0
0
0
0
1
1
1
1
0
1
W0-W7
W8-W15
Base and Current
Address
Write
0
0
1
1
0
0
0
0
1
1
0
0
0
0
0
1
A0-A7
A8-A15
Current Address
Read
0
0
0
0
1
1
0
0
1
1
0
0
0
0
0
1
A0-A7
A8-A15
Base and Current Word
Count
Write
0
0
1
1
0
0
0
0
1
1
0
0
1
1
0
1
W0-W7
W8-W15
Current Word Count
Read
0
0
0
0
1
1
0
0
1
1
0
0
1
1
0
1
W0-W7
W8-W15
Base and Current
Address
Write
0
0
1
1
0
0
0
0
1
1
1
1
0
0
0
1
A0-A7
A8-A15
Current Address
Read
0
0
0
0
1
1
0
0
1
1
1
1
0
0
0
1
A0-A7
A8-A15
Base and Current Word
Count
Write
0
0
1
1
0
0
0
0
1
1
1
1
1
1
0
1
W0-W7
W8-W15
Current Word Count
Read
0
0
0
0
1
1
0
0
1
1
1
1
1
1
0
1
W0-W7
W8-W15
CHANNEL
0
1
2
3
REGISTER
DATA BUS
DB0-DB7
FIGURE 11. WORD COUNT AND ADDRESS REGISTER COMMAND CODES
Application Information
Figure 12 shows an application for a DMA system utilizing
the HS-82C37ARH DMA controller and the HS-80C86RH
Microprocessor. In this application, the HS-82C37ARH DMA
controller is used to improve system performance by
allowing an I/O device to transfer data directly to or from
system memory.
Components
The system clock is generated by the HS-82C85RH clock
controllers generator and is inverted to meet the clock high
and low times required by the HS-82C37ARH DMA
controller. The four OR gates are used to support the
HS-80C86RH Microprocessor in minimum mode by
producing the control signals used by the processor to
access memory or I/O. A decoder is used to generate chip
select for the DMA controller and memory. The
HS-82C37ARH multiplexes the most significant bits of the
address on its data outputs (DB0 - 7), so the 82C82 octal
latch is used to demultiplex the address. A three-state
19
inverter is used to generate the BHE signal using the A0
output of the HS-82C37ARH. Hold Acknowledge (HLDA)
and Address Enable (AEN) are “ORed” together and used to
deactivate the microprocessors 82C82 transceiver to insure
that the DMA controller does not have bus contention with
the microprocessor.
Operation
A DMA request (DREQ) is generated by the I/O device. After
receiving the DMA request, the DMA controller will issue a
Hold Request (HRQ) to the processor. The system busses
are not released to the DMA controller until a Hold
Acknowledge (HLDA) signal is returned to the DMA
controller from the HS-80C86RH processor. After the Hold
Acknowledge has been received, addresses and control
signals are generated by the DMA controller to accomplish
the DMA transfers. Data is transferred directly from the I/O
device to memory (or vice versa) with IOR and MEMW (or
MEMR and IOW) being active. Note that data is not read into
or driven out of the DMA controller in I/O-to-Memory or
Memory-to-I/O data transfers.
HS-82C37ARH
MEMCS
HLDA
VDD
DECODER
HS-82C37ARH
HS-82C85RH
HLDA
HRQ
ALE
STB
AD0
CLK
ADDRESS
BUS
CLK
CS
ADSTB
AEN
OE
EOP
HLDA
IOR
IOW
AD15
MEMR
STB
82C82
M/10
RD
WR
BHE
OE
VDD
MEMW
HRQ
82C82
A0-7
DATA BUS
MN/MX
DB0-7
DREQ0
DACK0
HS-80C86RH
BHE
A0
MEMR
MEMW
ADDRESS BUS
I/O
DEVICE
IOR
CS
MEMORY
IOW
MEMCS
DREQ
DATA BUS
IOR
MEMR
MEMW
IOW
FIGURE 12. APPLICATION FOR DMA SYSTEM
20
HS-82C37ARH
Die Characteristics
DIE DIMENSIONS:
Top Metallization:
215mils x 232mils x 19mils ±1mil
Type: Al/Si
Thickness: 11kÅ ± 2kÅ
INTERFACE MATERIALS:
ADDITIONAL INFORMATION:
Glassivation:
Worst Case Current Density:
Thickness: 8kÅ ± 1kÅ
7.9 x 104 A/cm2
Metallization Mask Layout
(35) A3
(36) EOP
(37) A4
(38) A5
(39) A6
(40) A7
(1) IOR
(2) IOW
(3) MEMR
(4) MEMW
(5) NC
(6) READY
HS-82C37ARH
HLDA (7)
(34) A2
ADSTB (8)
(33) A1
AEN (9)
(32) A0
HRQ (10)
(31) VDD
CS (11)
(30) DB0
(29) DB1
CLK (12)
(28) DB2
RESET (13)
(27) DB3
DACK2 (14)
DACK0 (25)
DACK1 (24)
DB5 (23)
DB6 (22)
DB7 (21)
VSS (20)
DREQ0 (19)
DREQ1 (18)
DREQ2 (17)
DREQ3 (16)
DACK3 (15)
(26) DB4
All Intersil semiconductor products are manufactured, assembled and tested under ISO9000 quality systems certification.
Intersil semiconductor products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design and/or specifications at any time without notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and
reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result
from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries.
For information regarding Intersil Corporation and its products, see web site www.intersil.com
21
Similar pages