Mini retains the locked channels 1–4 from the full module. It uses two dual motor drivers for four motors. Drivers 3 and 4 are omitted; no remaining connection is moved. Physical pin numbers refer to the Pi 40-pin header; GPIO numbers are BCM.
| Channel | Default name | Mecanum wheel | Driver / output | Forward wire | Reverse wire | Driver ground |
|---|---|---|---|---|---|---|
| 1 | driver_1a | front_left | Driver 1 / A | pin 37 / GPIO26 → IN1 | pin 35 / GPIO19 → IN2 | pin 39 |
| 2 | driver_1b | rear_left | Driver 1 / B | pin 33 / GPIO13 → IN3 | pin 31 / GPIO6 → IN4 | pin 39 |
| 3 | driver_2a | front_right | Driver 2 / A | pin 40 / GPIO21 → IN1 | pin 38 / GPIO20 → IN2 | pin 34 |
| 4 | driver_2b | rear_right | Driver 2 / B | pin 36 / GPIO16 → IN3 | pin 32 / GPIO12 → IN4 | pin 34 |
Motor outputs A and B connect to their respective motors. Supply each driver from switched 12 V and return its power ground directly to battery ground; Pi ground wires carry the signal reference, not motor current.
| Pi connection | PCA9685 connection |
|---|---|
| pin 1 / 3.3 V | VCC, logic only |
| pin 3 / GPIO2 | SDA |
| pin 5 / GPIO3 | SCL |
| pin 7 / GPIO4 | OE, active low |
| pin 9 / GND | Logic GND |
Use address 0x40 with all address pads open. Servo V+ comes from its own regulated supply; join its return at common ground. Never connect V+ or motor battery positive to a Pi header pin. All sixteen PWM / V+ / GND output headers remain available.
| Pi connection | IMU connection |
|---|---|
| pin 17 / 3.3 V | VCC / VIN |
| pin 6 / GND | GND |
| pin 11 / GPIO17 | SDA |
| pin 12 / GPIO18 | SCL |
| pin 20 / GND | AD0, selects 0x68 |
Keep CS high for I²C (verify the board's pull-up); leave INT and auxiliary pins
disconnected. The installer enables i2c-gpio with SDA 17 and SCL 18.
Reboot after installation. Use the same IMU setup and robot API.
The former Driver 3 and 4 signal pins (13, 15, 16, 18, 21, 23, 24, 26) and
signal ground pins 14 and 25 stay disconnected on Mini. Pins 8/10 are reserved
for UART and 27/28 for ID EEPROM. Pins 2/4 are unused 5 V power pins; pins 19,
22 and 29 are unused GPIOs and pin 30 is an unused ground. Changing a motor's
inverted value changes its direction without changing this wiring.