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Semiconductor
MSM82C37B-5RS/GS/VJS
PIN FUNCTIONS
Power
VCC
Symbol
Pin Name
—
Input/Output
Function
+5 V power supply
Ground
GND
—
Ground (0 V) connection.
Clock
CLK
Input
Control of MSM82C37B-5 internal operations and data transfer
speed.
Chip Select
CS
Input
CS is active-low input signal used for the CPU to select
the MSM82C37B-5 as an I/O device in an idle cycle.
Hold Acknowledge
HLDA
Input
HLDA is active-high input signal used to indicate that system bus
control has been released when a hold request is recieved by
the CPU.
Reset
RESET
Input
RESET is active-high asynchrounous input signal used to clear
command, status, request, temporary registers, and first/last F/F,
and to set mask register. The MSM82C37B-5 enters an idle cycle
following a RESET.
Ready
READY
Input
The read or write pulse width can be extended to accomodate
slow access memories and I/O devices when this input is
switched to low level. Note this input must not change within
the prescribed set-up/hold time.
I/O Read
IOR
Input/Output
IOR is active-low bidirectional three-state signal used as an input
control signal for CPU reading of MSM82C37B-5 internal
registers during idle cycles, and as an output control signal for
reading I/O device transfer data in writing transfers during active
cycles.
I/O Write
IOW
Input/Output
IOW is active-low bidirectional three-state signal used as an input
control signal for CPU writing of MSM82C37B-5 internal registers
during idle cycles, and as an output control signal for writing I/O
device transfer data in writing transfers during active cycles.
DMA Request
0 - 3 Channels
DREQ0 -
DREQ3
Input
DREQ is asynchronous DMA transfer request input signals.
Although these pins are switched to active-high by reset, they can
be programmed to become active-low. DMA requests are
received in accordance with a prescribed order of priority. DREQ
must be held until DACK becomes active.
Data Bus 0 - 7
DB0 - DB7
Input/Output
DB is bidirectional three-state signals connected to the system
data bus, and which is used as an input/output of MSM82C37B-5
internal registers during idle cycles, and as an output of the eight
higher order bits of transfer addresses during active cycles.
Also used as input and output of transfer data during memory-
memory transfers.