DMA Controller. 82C37A Datasheet

82C37A Controller. Datasheet pdf. Equivalent

82C37A Datasheet
Recommendation 82C37A Datasheet
Part 82C37A
Description CMOS High Performance Programmable DMA Controller
Feature 82C37A; SEMICONDUCTOR 82C37A March 1997 CMOS High Performance Programmable DMA Controller Features Desc.
Manufacture Harris Corporation
Datasheet
Download 82C37A Datasheet




Harris Corporation 82C37A
SEMICONDUCTOR
82C37A
March 1997
CMOS High Performance
Programmable DMA Controller
Features
Description
• Compatible with the NMOS 8237A
• Four Independent Maskable Channels with Autoinitial-
ization Capability
• Cascadable to any Number of Channels
• High Speed Data Transfers:
- Up to 4MBytes/sec with 8MHz Clock
- Up to 6.25MBytes/sec with 12.5MHz Clock
• Memory-to-Memory Transfers
• Static CMOS Design Permits Low Power Operation
- ICCSB = 10µA Maximum
- ICCOP = 2mA/MHz Maximum
• Fully TTL/CMOS Compatible
• Internal Registers may be Read from Software
The 82C37A is an enhanced version of the industry standard
8237A Direct Memory Access (DMA) controller, fabricated
using Harris’ advanced 2 micron CMOS process. Pin
compatible with NMOS designs, the 82C37A offers
increased functionality, improved performance, and
dramatically reduced power consumption. The fully static
design permits gated clock operation for even further
reduction of power.
The 82C37A controller 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 fea-
ture. DMA requests may be generated by either hardware or
software, and each channel is independently programmable
with a variety of features for flexible operation.
The 82C37A is designed to be used with an external
address latch, such as the 82C82, to demultiplex the most
significant 8-bits of address. The 82C37A can be used with
industry standard microprocessors such as 80C286, 80286,
80C86, 80C88, 8086, 8088, 8085, Z80, NSC800, 80186 and
others. 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).
Ordering Information
5MHz
CP82C37A-5
IP82C37A-5
CS82C37A-5
IS82C37A-5
CD82C37A-5
ID82C37A-5
MD82C37A-5/B
5962-9054301MQA
MR82C37A-5/B
5962-9054301MXA
PART NUMBER
8MHz
CP82C37A
IP82C37A
CS82C37A
IS82C37A
CD82C37A
ID82C37A
MD82C37A/B
5962-9054302MQA
MR82C37A/B
5962-9054302MXA
12.5MHz
CP82C37A-12
IP82C37A-12
CS82C37A-12
IS82C37A-12
CD82C37A-12
ID82C37A-12
MD82C37A-12/B
5962-9054303MQA
MR82C37A-12/B
5962-9054303MXA
PACKAGE
40 Ld PDIP
44 Ld PLCC
40 Ld CERDIP
SMD#
44 Pad CLCC
SMD#
TEMPERATURE
RANGE
0oC to +70oC
-40oC to +85oC
0oC to +70oC
-40oC to +85oC
0oC to +70oC
-40oC to +85oC
-55oC to +125oC
-55oC to +125oC
PKG. NO.
E40.6
E40.6
N44.65
N44.65
F40.6
F40.6
F40.6
F40.6
J44.A
J44.A
CAUTION: These devices are sensitive to electrostatic discharge. Users should follow proper IC Handling Procedures.
Copyright © Harris Corporation 1997
4-192
File Number 2967.1



Harris Corporation 82C37A
Pinouts
82C37A (PDIP/CERDIP)
TOP VIEW
IOR 1
IOW 2
MEMR 3
MEMW 4
NC 5
READY 6
HLDA 7
ADSTB 8
AEN 9
HRQ 10
CS 11
CLK 12
RESET 13
DACK2 14
DACK3 15
DREQ3 16
DREQ2 17
DREQ1 18
DREQ0 19
(GND) VSS 20
40 A7
39 A6
38 A5
37 A4
36 EOP
35 A3
34 A2
33 A1
32 A0
31 VCC
30 DB0
29 DB1
28 DB2
27 DB3
26 DB4
25 DACK0
24 DACK1
23 DB5
22 DB6
21 DB7
82C37A
82C37A (CLCC/PLCC)
TOP VIEW
6 5 4 3 2 1 44 43 42 41 40
NC 7
39 A3
NC 8
38 A2
HLDA 9
37 A1
ADSTB 10
36 A0
AEN 11
35 VCC
HRQ 12
34 DB0
CS 13
33 DB1
CLK 14
32 DB2
RESET 15
31 DB3
DACK2 16
NC 17
30 DB4
29 NC
18 19 20 21 22 23 24 25 26 27 28
Block Diagram
EOP
RESET
CS
READY
CLK
AEN
ADSTB
MEMR
MEMW
IOR
IOW
TIMING
AND
CONTROL
DREQ0 -
DREQ3
HLDA
HRQ
DACK0 -
DACK3
4
4
PRIORITY
ENCODER
AND
ROTATING
PRIORITY
LOGIC
DECREMENTOR
TEMP WORD
COUNT REG (16)
INC/DECREMENTOR
TEMP ADDRESS
REG (16)
16-BIT BUS
16-BIT BUS
READ BUFFER
READ WRITE BUFFER
BASE
ADDRESS
(16)
BASE
WORD
COUNT
(16)
CURRENT
ADDRESS
(16)
CURRENT
WORD
COUNT
(16)
WRITE
BUFFER
READ
BUFFER
IO
BUFFER
A0 - A3
OUTPUT
BUFFER
A4 - A7
COMMAND
CONTROL
D0 - D1
COMMAND
(8)
MASK
(4)
REQUEST
(4)
INTERNAL DATA BUS
IO
BUFFER
MODE
(4 x 6)
STATUS
(8)
TEMPORARY
(8)
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Harris Corporation 82C37A
82C37A
Pin Description
PIN
SYMBOL NUMBER TYPE
DESCRIPTION
VCC
31
VCC: 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 82C37A
operations. This input may be driven from DC to 12.5MHz for the 82C37A-12, from DC to 8MHz for
the 82C37A, or from DC to 5MHz for the 82C37A-5. The Clock may be stopped in either 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
READY
6
HLDA
7
DREQ0-
DREQ3
16-19
DB0-DB7
21-23
26-30
IOR 1
IOW 2
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.
I READY: This signal can be used to extend the memory read and write pulses from the 82C37A to
accommodate slow memories or I/O devices. READY must not make transitions during its specified
set-up and hold times. See Figure 12 for timing. READY is ignored in verify transfer mode.
I HOLD ACKNOWLEDGE: The active high Hold Acknowledge from the CPU indicates that it has
relinquished control of the system busses. HLDA is a synchronous input and must not transition
during its specified set-up time. There is an implied hold time (HLDA inactive) of TCH from the rising
edge of CLK, during which time HLDA must not transition.
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 a DREQ signal. Polarity of DREQ is
programmable. RESET initializes these lines to active high. DREQ must be maintained until the
corresponding DACK goes 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.
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 82C37A control registers. During DMA cycles, the most signifi-
cant 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 82C37A 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.
I/O I/O READ: I/O Read is a bidirectional active low three-state line. In the Idle cycle, it is an input con-
trol signal used by the CPU to read the control registers. In the Active cycle, it is an output control
signal used by the 82C37A to access data from the peripheral during a DMA Write transfer.
I/O I/O WRITE: I/O Write is a bidirectional active low three-state line. In the Idle cycle, it is an input con-
trol signal used by the CPU to load information into the 82C37A. In the Active cycle, it is an output
control signal used by the 82C37A to load data to the peripheral during a DMA Read transfer.
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