Tandy 1000 HX Technical Reference Manual page 233

• 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
T O T A L P I N C O U N T = 6 8
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