30.5.3.3.2 “Special” Packets
The payload of “special” packets is interpreted by the OTPC and some actions can be triggered while the “special” packets are read. The address of the “special” packets inside the area does not matter.
If the checksum has been generated and does not match during the last read, the payload is not interpreted by the OTPC.
The table below provides the list of “special” packets.
| Name | SIZE | PACKET | Description |
|---|---|---|---|
| Boot Configuration | (see Note 1) | 3 | Boot configuration |
| Secure Boot Configuration | (see Note 1) | 4 | Secure Boot configuration |
| User Hardware Configuration | 1 | 5 | Hardware configuration |
| Custom | N/A | 6 | For user custom purposes. The size of this packet is user application dependent. |
- For details, refer to the section “Boot Strategies”.
The address of the Boot Configuration and Secure Boot Configuration special packets can be retrieved in the OTPC Boot Addresses (OTPC_BAR) register.
The address of the Custom special packets can be retrieved in the OTPC Custom Address (OTPC_CAR) register for non-secure packets and in the OTPC Secure Custom Address (OTPC_SCAR) register for secure packets.
For each “special” packets, if there is more than one valid packet (of the same type), only the last packet will be considered (previous packets will be ignored). It is recommended to invalidate prior “special” packets to keep only one valid packet for each “special” packet type.