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The general purpose input/output board (GPIO) is connected to the external wiring via to main connectors:
The connections on the 35 pin AMPSEAL connector are:
Circuit | CPU Port | AMP pin number |
| 12 Volts (IN) | n/a | 1 |
| VR1 | PT0 | 2 |
| GPI4 | PAD07 | 3 |
| GPI5 | PAD06 | 4 |
| GPI1 | PAD00 | 5 |
| GPI2 | PAD01 | 6 |
| GPO2 | PM3 | 7 |
| GPO3 | PM5 | 8 |
| GPO4 | PB4 | 9 |
| GPO1 | PM4 | 10 |
| VB1 | PE0 (PE0 is input only, so another port must be jumpered to VB1 to use that circuit) | 11 |
| VB2 | PA0 | 12 |
| CANH | (MCP2551) | 13 |
| VR3 | PT5 | 14 |
| VR2 | PT6 | 15 |
| CANL | (MCP2551) | 16 |
| Ground | n/a | 17 |
| Ground | n/a | 18 |
| Ground | n/a | 19 |
| Ground | n/a | 20 |
| Spare Pin (Serial Tx) | 12V/GND/5V - or serial | 21 |
| Spare Pin (Serial Rx) | 12V/GND/5V - or serial | 22 |
| VB3 | PE4 | 23 |
| EGT1 | PAD05 | 24 |
| EGT3 | PAD03 | 25 |
| EGT4 | PE1 | 26 |
| EGT2 | PAD04 | 27 |
| 5 Vref (OUT) | 28 | |
| VR4 | PT7 | 29 |
| GPI3 | PAD02 | 30 |
| PWM1 | PT4 | 31 |
| PWM2 | PT3 | 32 |
| PWM3 | PT2 | 33 |
| PWM4 | PT1 | 34 |
| VB4 | PM2 | 35 |
Unlike MegaSquirt® EFI Controller, the GPIO Board does not use a DB9 connector for serial communications. Instead it uses a 2.5 mm (aka. 3/32") sub-miniature stereo jack, of the same spec used for the Innovate LC-1 wide band controller:
