MC68HC908AT32 Datasheet, PDF (257/378 Pages) Freescale Semiconductor, Inc – Microcontrollers

Identifier Acceptance Filter
A filter hit is indicated to the application software by a set RXF (receiver buffer full flag, see
23.13.5 MSCAN08 Receiver Flag Register) and two bits in the identifier acceptance control register (see
23.13.9 MSCAN08 Identifier Acceptance Control Register). These identifier hit flags (IDHIT1–IDHIT0)
clearly identify the filter section that caused the acceptance. They simplify the application software’s task
to identify the cause of the receiver interrupt. When more than one hit occurs (two or more filters match),
the lower hit has priority.
ID28 IDR0 ID21 ID20 IDR1 ID15 ID14 IDR2
ID10 IDR0
ID3 ID2
IDR1 IDE ID10 IDR2
ID7 ID6
IDR3 RTR
ID3 ID10 IDR3 ID3
AC7 CIDMR0 AC0
AC7 CIDAR0 AC0
ID ACCEPTED (FILTER 0 HIT)
AC7 CIDMR1 AC0
AC7 CIDAR1 AC0
ID ACCEPTED (FILTER 1 HIT)
AC7 CIDMR2 AC0
AC7 CIDAR2 AC0
ID ACCEPTED (FILTER 2 HIT)
AC7 CIDMR3 AC0
AC7 CIDAR3 AC0
ID ACCEPTED (FILTER 3 HIT)
Figure 23-5. Quadruple 8-Bit Maskable Acceptance Filters
MC68HC908AT32 Data Sheet, Rev. 3.1
Freescale Semiconductor
257