PIC18FXX8 Datasheet, PDF (233/402 Pages) Microchip Technology – 28/40-Pin High-Performance, Enhanced Flash Microcontrollers with CAN Module

PIC18FXX8
FIGURE 19-5:
INTERNAL MESSAGE RECEPTION FLOWCHART
Start
No
Detect
Start of
Message?
Yes
Begin Loading Message into
Message Assembly Buffer (MAB)
Generate
Error
Frame
No
Valid
Message
Received?
Yes
Yes, meets criteria
Yes, meets criteria
for RXBO
Message
for RXB1
Identifier meets a
Filter Criteria?
No
The RXFUL bit determines if the
receive register is empty and able
to accept a new message.
Go to Start
The RXB0DBEN bit determines if
RXB0 can rollover into RXB1 if it is
full.
Is
No
RXFUL = 0?
Is
Yes
RX0DBEN = 1?
Yes
Move Message into RXB0
No
Generate Overrun Error:
Set RXB0OVFL
Generate Overrun Error: ^No
Set RXB1OVFL
Is
RXFUL = 0?
Set RXRDY = 1
Set FILHIT <0>
according to which Filter
Criteria was met
Is
No
ERRIE = 1?
Yes
Go to Start
Yes
Move Message into RXB1
Set RXRDY = 1
Set FILHIT <2:0>
according to which Filter
Criteria was met
Is
Yes
RXIE = 1?
No
Generate
Interrupt
Set CANSTAT <3:0> according
to which Receive Buffer the
Message was loaded into
Yes
Is
RXIE = 1?
No
 2004 Microchip Technology Inc.
DS41159D-page 231