PIC18F248-E/L MICROCHIP [Microchip Technology], PIC18F248-E/L Datasheet - Page 231

• Manufacturer Part Number: PIC18F248-E/L
• Description: 28/40-Pin High-Performance, Enhanced Flash Microcontrollers with CAN Module
• Manufacturer: MICROCHIP [Microchip Technology]

FIGURE 19-3:
© 2006 Microchip Technology Inc.
The TXIE bit determines if an inter-
rupt should be generated when a
message is successfully transmitted.
Generate
Interrupt
INTERNAL TRANSMIT MESSAGE FLOWCHART
Determine Highest Priority Message
No
Yes
Begin Transmission (SOF)
Examine TXPRI <1:0> to
Clear: TXABT, TXLARB
Message Transmitted
Available to Start
Transmission?
Set TXREQ = 0
Successfully?
TXBUFE = 1
and TXERR
Is CAN bus
TXIE = 1?
TXREQ
bits = 1?
Are any
Start
END
Was
Set
Is
Yes
Yes
Yes
No
A message can also be
aborted if a message
error or lost arbitration
condition occurred during
transmission.
No
No
The message transmission sequence begins when
the device determines that the TXREQ for any of the
transmit registers has been set.
Clearing the TXREQ bit while it is set, or setting
the ABAT bit before the message has started
transmission, will abort the message.
or TXABT = 1?
TXLARB = 1?
TXREQ = 0
ABAT = 1?
TXERR = 1
TXREQ = 0
No
No
Set
Is
Is
Is
No
Yes
Yes
Yes
Abort Transmission:
Set TXABT = 1
PIC18FXX8
Arbitration Lost During
Transmission
DS41159E-page 229