A protected identifier consists of two subfields: the identifier and the identifier parity. Bits 0 to 5 are assigned to the identifier and bits 6 and 7 are assigned to the parity.
The USART interface can generate/check these parity bits, but this feature can also be disabled. The user can choose between two modes using US_LINMR.PARDIS:
- PARDIS = 0:
- During header transmission, the parity bits are computed and sent with the six least significant bits of US_LINIR.IDCHR. The bits 6 and 7 of this register are discarded.
- During header reception, the parity bits of the identifier
are checked. If the parity bits are wrong, an Identifier Parity error occurs (see
Parity). Only the six least significant bits of the IDCHR field are
updated with the received Identifier. The bits 6 and 7 are stuck to 0.
- PARDIS = 1:
- During header transmission, all the bits of US_LINIR.IDCHR are sent on the bus.
- During header reception, all the bits of IDCHR are updated with the received Identifier.