Hi @DaveG8GKQ,
To be precise, fan is controlled by on-board temperature sensor by default.
This is the function:
LMS_WriteFPGAReg(lms_device_t *device, uint32_t address, uint16_t val);
Use this sequence to turn fan on:
LMS_WriteFPGAReg(DEVICE, 0xCC, 0x01); // Enable manual fan control
LMS_WriteFPGAReg(DEVICE, 0xCD, 0x01); // Turn fan on