SPI transactions

All SPI transactions start with a high-to-low transition on the CS pin. The CS pin must be held low during the entire SPI transaction.

The IRQ_FLAGS register is always shifted out as the first byte of each transaction.

SPI commands

All SPI command sequences, except for the NOP command, consist of two SPI transactions. The first transaction shall be one byte long, this is the command byte. The second transaction is the payload. The second transaction must not be started until the Vision Controller has confirmed the command by a high-to-low transition on the IRQ pin. The first byte being sent to Vision Controller in the second transaction must be sent as 0xFF. See below for an example full SPI command sequence.