MC68HC912DG128 Datasheet, PDF (315/452 Pages) Motorola, Inc – Microcontrollers

Freescale Semiconductor, Inc.
MSCAN Controller
Message Storage
On reception, each message is checked to see if it passes the filter (for
details see Identifier Acceptance Filter) and in parallel is written into
RxBG. The msCAN12 copies the content of RxBG into RxFG⁽¹⁾, sets the
RXF flag, and generates a receive interrupt to the CPU⁽²⁾. The user’s
receive handler has to read the received message from RxFG and then
reset the RXF flag in order to acknowledge the interrupt and to release
the foreground buffer. A new message, which can follow immediately
after the IFS field of the CAN frame, is received into RxBG.
The over-writing of the background buffer is independent of the identifier
filter function.
1. Only if the RXF flag is not set.
2. The receive interrupt is generated only if not masked. A polling scheme can be applied on RXF
also.
MC68HC912DG128 — Rev 3.0
MOTOROLA
MSCAN Controller
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Technical Data
315