PIC18C658 MICROCHIP [Microchip Technology], PIC18C658 Datasheet - Page 212

• Manufacturer Part Number: PIC18C658
• Description: High-Performance Microcontrollers with CAN Module
• Manufacturer: MICROCHIP [Microchip Technology]

PIC18CXX8
FIGURE 17-2: TRANSMIT MESSAGE FLOWCHART
DS30475A-page 212
The TXIE bit determines if an inter-
rupt should be generated when a
message is successfully transmitted.
Generate
Interrupt
Examine TXPRI <1:0> to
Determine Highest Priority Message
Yes
No
Clear: TXABT, TXLARB,
Begin transmission (SOF)
Message Transmitted
to start transmission
CAN bus available
and TXERR
Set TXREQ = 0
Successfully?
TXBUFE = 1
Yes
TXIE = 1?
TXREQ
Are any
Start
bits = 1
END
Was
Set
Is
?
?
Is
Yes
Yes
Advanced Information
No
No
The message transmission sequence begins when
the device determines that the TXREQ for any of the
transmit registers has been set.
TXLARB = 1?
or TXABT = 1
TXREQ = 0
TXERR = 1
No
No
Set
Is
is
?
TXREQ = 0
Clearing the TXREQ bit while it is set, or setting
the ABAT bit before the message has started
transmission will abort the message.
ABAT = 1
Is
?
Yes
Yes
Yes
Abort Transmission:
Set TXABT = 1
Arbitration lost during
No
transmission
A message can also be
aborted if a message
error or lost arbitration
condition occurred during
transmission.
2000 Microchip Technology Inc.