This is the set of values that the high-level HAL IIC API calls should return to RISC OS:
IICSTATUS_COMPLETED | 0 | The transfer completed successfully |
IICSTATUS_INPROGRESS | 1 | The transfer has started and is proceeding in the background |
IICSTATUS_NOACK | 2 | Slave failed to acknowledge |
IICSTATUS_BUSY | 3 | IIC system busy, transfer could not be started (call back later) |
IICSTATUS_SLAVE | 4 | Reserved for slave operations |
IICSTATUS_ERROR | 5 | Another error prevented completion of the transfer |