mc68hc08qa24 Freescale Semiconductor, Inc, mc68hc08qa24 Datasheet - Page 364

• Manufacturer Part Number: mc68hc08qa24
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

CAN Controller
22.13.5 Transmit Buffer Priority Registers
Technical Data
362
NOTE:
Address:
PRIO7–PRIO0 — Local Priority Bits
To ensure data integrity, no registers of the transmit buffers shall be
written while the associated TXE flag is cleared.
To ensure data integrity, no registers of the receive buffer shall be read
while the RXF flag is cleared.
Reset:
Read:
Write:
This field defines the local priority of the associated message buffer.
The local priority is used for the internal priorisation process of the
MSCAN08 and is defined to be highest for the smallest binary
number. The MSCAN08 implements the following internal priorisation
mechanism:
•
•
•
Figure 22-12. Transmit Buffer Priority Register (TBPR)
All transmission buffers with a cleared TXE flag participate in the
prioritization right before the SOF is sent.
The transmission buffer with the lowest local priority field wins the
prioritization.
In case more than one buffer has the same lowest priority, the
message buffer with the lower index number wins.
PRIO7
$xxxD
Bit 7
0
PRIO6
CAN Controller
6
0
PRIO5
5
0
PRIO4
4
0
PRIO3
3
0
PRIO2
Freescale Semiconductor
2
0
MC68HC08QA24
PRIO1
1
0
PRIO0
Bit 0
0