HS9-82C37ARH/SAMPLE HARRIS [Harris Corporation], HS9-82C37ARH/SAMPLE Datasheet - Page 4

• Manufacturer Part Number: HS9-82C37ARH/SAMPLE
• Description: Radiation Hardened CMOS High Performance Programmable DMA Controller
• Manufacturer: HARRIS [Harris Corporation]

Pin Descriptions
SYMBOL
DACK0-
DACK3
ADSTB
MEMW
MEMR
A4-A7
HRQ
AEN
NC
14,15, 24,
NUMBER
37-40
PIN
10
25
9
8
3
4
5
TYPE
(Continued)
O
O
O
O
O
O
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.
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 bus-
ses 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.
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.
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.
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 op-
erations, ADSTB will only be issued when the upper address byte must be updated, thus speeding op-
eration through elimination of S1 states. (See Note 2).
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.
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.
No connect. Pin 5 is open and should not be tested for continuity.
HS-82C37ARH
4
DESCRIPTION
Spec Number
518058