Pin |
Name |
Dir |
Description |
1 |
+8V |
|
+5V 3-T regulator voltage supply (about +8V) |
2 |
+8V |
|
+5V 3-T regulator voltage supply (about +8V) |
3 |
GND |
|
Ground |
4 |
READYA |
|
System ready (10K pull-up to +5V) |
5 |
GND |
|
Ground |
6 |
RESET* |
|
System reset (active low) |
7 |
GND |
|
Ground |
8 |
SCLK |
nc |
System clock (not connected) |
9 |
LCP* |
nc |
CPU indicator 1=TI99 0=2nd generation (not connected) |
10 |
AUDIO |
|
Input audio (=AUDIOIN) |
11 |
RDBENA* |
|
Active low: enable flex cable data bus drivers (1K pull-up) |
12 |
PCBEN |
H |
PCB enable for burn-in (always High) |
13 |
HOLD* |
H |
Active low CPU hold request (always High) |
14 |
IAQHA |
nc |
IAQ [or] HOLDA (logical or) |
15 |
SENILA* |
H |
Interrupt level A sense enable (always High) |
16 |
SENILB* |
H |
Interrupt level B sense enable (always High) |
17 |
INTA* |
|
Active low interrupt level A (=EXTINT*) |
18 |
LOAD* |
nc |
Unmaskable interrupt (not connected) |
19 |
D7 |
|
Data bit 7 (LSB) |
20 |
GND |
|
Ground |
21 |
D5 |
|
Data bit 5 |
22 |
D6 |
|
Data bit 6 |
23 |
D3 |
|
Data bit 3 |
24 |
D4 |
|
Data bit 4 |
25 |
D1 |
|
Data bit 1 |
26 |
D2 |
|
Data bit 2 |
27 |
GND |
|
Ground |
28 |
D0 |
|
Data bit 0 (MSB) |
29 |
A14 |
|
Address bit 14 |
30 |
A15 |
|
Address bit 15 (LSB). Also CRU output bit. |
31 |
A12 |
|
Address bit 12 |
32 |
A13 |
|
Address bit 13 |
33 |
A10 |
|
Address bit 10 |
34 |
A11 |
|
Address bit 11 |
35 |
A8 |
|
Address bit 8 |
36 |
A9 |
|
Address bit 9 |
37 |
A6 |
|
Address bit 6 |
38 |
A7 |
|
Address bit 7 |
39 |
A4 |
|
Address bit 4 |
40 |
A5 |
|
Address bit 5 |
41 |
A2 |
|
Address bit 2 |
42 |
A3 |
|
Address bit 3 |
43 |
A0 |
|
Address bit 0 (MSB) |
44 |
A1 |
|
Address bit 1 |
45 |
AMB |
H |
Extra address bit. Always High. |
46 |
AMA |
H |
Extra address bit. Always High. |
47 |
GND |
|
Ground |
48 |
AMC |
H |
Extra address bit. Always High. |
49 |
GND |
|
Ground |
50 |
CLKOUT* |
|
Inversion of phase 3 clock (=PHI3*) |
51 |
CRUCLK* |
|
Inversion of TMS9900 CRUCLOCK pin |
52 |
DBIN |
|
Active high = read memory |
53 |
GND |
|
Ground |
54 |
WE* |
|
Write Enable (derived from TMS9900 WE* pin) |
55 |
CRUIN |
|
CRU input bit to TMS9900 |
56 |
MEMEN* |
|
Memory access enable (active low) |
57 |
-12V |
|
-12 Volts 3-T regulator supply voltage (about -16V) |
58 |
-12V |
|
-12 Volts 3-T regulator supply voltage (about -16V) |
59 |
+12V |
|
+12 Volts 3-T regulator supply voltage (about +16V) |
60 |
+12V |
|
+12 Volts 3-T regulator supply voltage (about +16V) |
Direction is computer relative world.