Model Builder supports several types of Watchdog Timer signals via the parallel port. The table below lists the corresponding parallel port bit number, the watchdog timer signal description, and the Model Builder version where the signal was first implemented.
Care should be taken when interfacing to the DACS parallel port as improper interface could cause parallel poert of possibly CPU failure.
| Active | |||||
|---|---|---|---|---|---|
| Pin | Bit | Function | Toggle | High | MB Version |
| 2 | 0 | Model Builder (MB) Running | X | 3.03+ | |
| 3 | 1 | Model Builder running w/ no errors | X | ||
| 4 | 2 | Model Builder running w/ no errors | X | 3.03+ | |
| 5 | 3 | MB running; DSPs running OK | X | 3.03+ | |
| 6 | 4 | DSPs not muted | X | 3.04+ | |
| 7 | 5 | MB running; main Rx packet from host active | X | 3.03+ | |
| 8 | 6 | No system errors | X | 3.04+ | |
| Pin | Description | I/O |
|---|---|---|
| 1 | -Strobe | Out |
| 2 | +Data Bit 0 | Out |
| 3 | +Data Bit 1 | Out |
| 4 | +Data Bit 2 | Out |
| 5 | +Data Bit 3 | Out |
| 6 | +Data Bit 4 | Out |
| 7 | +Data Bit 5 | Out |
| 8 | +Data Bit 6 | Out |
| 9 | +Data Bit 7 | Out |
| 10 | -Acknowledge | Out |
| 11 | +Busy | In |
| 12 | +Paper End | In |
| 13 | +Select | In |
| 14 | -Auto Feed | Out |
| 15 | -Error | In |
| 16 | -Initialize Printer | Out |
| 17 | -Select Input | Out |
| 18 | -Data Bit 0 Return (GND) | In |
| 19 | -Data Bit 1 Return (GND) | In |
| 20 | -Data Bit 2 Return (GND) | In |
| 21 | -Data Bit 3 Return (GND) | In |
| 22 | -Data Bit 4 Return (GND) | In |
| 23 | -Data Bit 5 Return (GND) | In |
| 24 | -Data Bit 6 Return (GND) | In |
| 25 | -Data Bit 7 Return (GND) | In |