Available on TI-99/4A computers. On the top
| Pin |
Name |
Dir |
Description |
| 1 |
RESET |
IN |
Resets the system (active high) |
| 2 |
GND |
- |
Signal groud |
| 3 |
D7 |
IN/OUT |
Data bus, bit 7 (least significant) |
| 4 |
CRUCLK* |
OUT |
Inversion of TMS9900 CRUCLOCK pin |
| 5 |
D6 |
IN/OUT |
|
| 6 |
CRUIN |
IN |
CRU input to TMS9900 |
| 7 |
D5 |
IN/OUT |
|
| 8 |
A15 |
OUT |
Address bus, bit 15 / also CRU output bit |
| 9 |
D4 |
IN/OUT |
|
| 10 |
A13 |
OUT |
|
| 11 |
D3 |
IN/OUT |
|
| 12 |
A12 |
OUT |
|
| 13 |
D2 |
IN/OUT |
|
| 14 |
A11 |
OUT |
|
| 15 |
D1 |
IN/OUT |
|
| 16 |
A10 |
OUT |
|
| 17 |
D0 |
IN/OUT |
Data bus, bit 0 (most significant) |
| 18 |
A9 |
OUT |
|
| 19 |
VCC |
- |
+5 Volts power supply |
| 20 |
A8 |
OUT |
|
| 21 |
GS* |
OUT |
Grom select. Active low is addr in >9800-9FFF |
| 22 |
A7 |
OUT |
|
| 23 |
A14 |
OUT |
Address bus, bit 14. Select mode: low=data / high=addr |
| 24 |
A3 |
OUT |
|
| 25 |
DBIN |
OUT |
Active high = read memory |
| 26 |
A6 |
OUT |
|
| 27 |
GRC |
OUT |
GROM clock: color burst of VDP 9918A |
| 28 |
A5 |
OUT |
|
| 29 |
VDD |
- |
-5 Volts power supply |
| 30 |
A4 |
OUT |
|
| 31 |
GR |
IN |
Active high = GROM ready |
| 32 |
WE* |
OUT |
Active low = write enable (derived from TMS9900 WE*) |
| 33 |
VSS |
- |
|
| 34 |
ROMG* |
OUT |
Active low if addr in >6000-7FFF |
| 35 |
GND |
- |
Ground |
| 36 |
GND |
- |
Ground |