Transfer a Packet through the Host Key Bus

To transfer a packet from the OTP memory through the host key bus, follow the steps below:

1. The address of the header (or any address of the payload) must be written in OTPC_MR.ADDR. Only the packets with the packet type set to KEY are transferable on the host key bus.
2. The key bus destination must be written in OTPC_MR.KBDST.
3. Write 0x7167in the OTPC_CR.KEY field and ‘1’ to OTPC_CR.KBSTART.

The end of the transfer is indicated by OTPC_ISR.EOKT=’1’ and/or OTPC_SR.MKBB=’0’.

If the type of the packet is not KEY, OTPC_ISR.KBERR is set.

To cancel a packet transfer, OTPC_CR.KEY must be set to 0x7167 and KBSTOP must be set.