XC912BC32CFU8 Motorola Semiconductor Products, XC912BC32CFU8 Datasheet - Page 266

• Manufacturer Part Number: XC912BC32CFU8
• Description: M68HC12B Family Data Sheet
• Manufacturer: Motorola Semiconductor Products

msCAN12 Controller
Data Sheet
266
When the msCAN12 module is transmitting, the msCAN12 receives its own
messages into the background receive buffer, RxBG, but does not overwrite RxFG,
generate a receive interrupt, or acknowledge its own messages on the CAN bus.
The exception to this rule is in loop-back mode (see
Control
other incoming messages. The msCAN12 receives its own transmitted messages
in the event that it loses arbitration. If arbitration is lost, the msCAN12 must be
prepared to become the receiver.
An overrun condition occurs when both the foreground and the background receive
message buffers are filled with correctly received messages with accepted
identifiers and another message is correctly received from the bus with an
accepted identifier. The latter message is discarded and an error interrupt with
overrun indication is generated if enabled. The msCAN12 is still able to transmit
messages with both receive message buffers filled, but all incoming messages are
discarded.
Register1) where the msCAN12 treats its own messages exactly like all
Figure 16-2. User Model for Message Buffer Organization
msCAN12
msCAN12 Controller
RxBG
Tx0
RxFG
Tx1
Tx2
PRIO
PRIO
PRIO
RXF
TXE
TXE
TXE
16.12.2 msCAN12 Module
CPU BUS
M68HC12B Family — Rev. 8.0
MOTOROLA