PIC18F2682 Datasheet, PDF (331/484 Pages) Microchip Technology – 28/40/44-Pin Enhanced Flash Microcontrollers with ECAN Technology, 10-Bit A/D and nanoWatt Technology

PIC18F2682/2685/4682/4685
23.6.3 TRANSMIT PRIORITY
Transmit priority is a prioritization within the
PIC18F2682/2685/4682/4685 devices of the pending
transmittable messages. This is independent from and
not related to any prioritization implicit in the message
arbitration scheme built into the CAN protocol. Prior to
sending the SOF, the priority of all buffers that are
queued for transmission is compared. The transmit
FIGURE 23-2:
TRANSMIT BUFFERS
TXB0
TXB1
buffer with the highest priority will be sent first. If two
buffers have the same priority setting, the buffer with
the highest buffer number will be sent first. There are
four levels of transmit priority. If TXP bits for a particular
message buffer are set to ‘11’, that buffer has the high-
est possible priority. If TXP bits for a particular message
buffer are set to ‘00’, that buffer has the lowest possible
priority.
TXB2
TXB3 - TXB8
Message
Queue
Control
Transmit Byte Sequencer
© 2007 Microchip Technology Inc.
Preliminary
DS39761B-page 329