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TANDY COMPUTER PRODUCTS -
OUTPUTS:
(20 pins)
MAO0-MAO8
RAS0B-RAS2B
CASB
WRB
DBDIR
DBENB
REFRESHB
DACK1B
FDCDMACKB
DACK3B
DMATC
BREQB
POWER: (4 pins)
VDD
VSS
External Memory multiplexed address
External Memory ROW strobes.
External Memory COLUMN strobe.
External Memory WRITE strobe.
Data Buffer directional control
(Read=l).
Data Buffer enable.
8237 CHANNEL
0
ACKNOWLEDGE (DREQO)
Acknowledge from DMA channel
0
setup for
refresh.
8237 CHANNEL
1
ACKNOWLEDGE (DREQl)
8237 CHANNEL
2
ACKNOWLEDGE (DREQ2)
8237 CHANNEL
3
ACKNOWLEDGE (DREQ3)
8237 EOP (output only)
CPU Bus Request (8237 HRQ)
+5 VDC
GND
TOTAL
PIN
COUNT
=68
PIN SENSE
BIDIR
BIDIR
BIDIR
BIDIR
TSFBAK
TSFBAK
TSFBAK
TSFBAK
TSFBAK
TSFBAK
TSFBAK
TSFBAK
TSFBAK
TSFBAK
TSFBAK
TSFBAK
TSFBAK
TSFBAK
TSFBAK
TSFBAK
DMA 1
PINOUT
AO
-
Al
A2
(BIDIR ENA
-
=
DMAAEN)
A3
-
A4
-
A5
A6
(TS ENA
-
=
DMAAEN)
A7
-
A8
A9
A10
All
A12
A13
A14
A15
A16
A17
A18
A19
8237 PINOUT
AO
Al
A2
(BIDIR ENA
- =8237 CNTL)
A3
A4
A5
A6
(TS ENA
= LOGIC
1)
A7