68HC912DG128 Datasheet, PDF (291/424 Pages) Motorola, Inc – Advance Information

MSCAN Controller
Message Storage
RXF flag, and generates a receive interrupt to the CPU¹. 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.
msCAN12
RxBG
RxFG
RXF
CPU bus
5-mscan12
MOTOROLA
Tx0
TXE
PRIO
Tx1
TXE
PRIO
Tx2
TXE
PRIO
Figure 44 User Model for Message Buffer Organization
1. Only if the RXF flag is not set.
1. The receive interrupt is generated only if not masked. A polling scheme can be applied on
RXF also.
MSCAN Controller
68HC(9)12DG128 Rev 1.0
291