TIM9904 (SN74LS362) four-phase clock generator pinout
DIP-20. Makes the four-phase 12 V clock for the 9900 (3 MHz) and the power-on reset.
Makes the four MOS-level clock phases (pins 12, 11, 8, 9) for the 9900, plus inverted TTL copies, from a crystal and tank circuit. TI fits a 48 MHz third-overtone crystal with an LC tank on pins 1 and 2 (some consoles use 12 MHz); either way the phases run at 3 MHz. Its D flip-flop (FFD pin 5 in, FFQ pin 4 out) is the console reset. Needs +12 V on pin 13 and +5 V on pin 20. A missing clock or a reset stuck low gives a dead console.
Open the interactive TIM9904 pinoutPins
| Pin | Name | Type | Signal |
|---|---|---|---|
| 1 | TANK1 | clock | Tank circuit connection (the LC that selects the crystal overtone). |
| 2 | TANK2 | clock | Tank circuit connection. |
| 3 | GND1 | ground | Ground reference. |
| 4 | FFQ | ctrl | D flip-flop output, clocked by phase 3. On the TI it is the reset to the 9900 /RESET. |
| 5 | FFD | ctrl | D input of the Schmitt-trigger flip-flop. On the TI: the power-on RC (R605, C606). |
| 6 | /PHI4 TTL | clock | TTL phase 4, inverted. |
| 7 | /PHI3 TTL | clock | TTL phase 3, inverted. |
| 8 | PHI3 | clock | MOS phase 3 (12 V swing) to 9900 pin 28. |
| 9 | PHI4 | clock | MOS phase 4 to 9900 pin 25. |
| 10 | GND2 | ground | Ground reference (second ground). |
| 11 | PHI2 | clock | MOS phase 2 to 9900 pin 9. |
| 12 | PHI1 | clock | MOS phase 1 to 9900 pin 8. |
| 13 | Vdd | power | +12 V supply for the MOS clock drivers. |
| 14 | /PHI1 TTL | clock | TTL phase 1, inverted. |
| 15 | /PHI2 TTL | clock | TTL phase 2, inverted. |
| 16 | OSCOUT | clock | Oscillator output (4 x the phase frequency). |
| 17 | OSCIN | clock | TTL external oscillator input. On the TI it is tied to +5 V through R604, which enables the crystal oscillator. |
| 18 | XTAL1 | clock | Crystal. 48 MHz third overtone on most consoles; some use 12 MHz. |
| 19 | XTAL2 | clock | Crystal (other side). |
| 20 | Vcc | power | +5 V supply. |