FlexCAN Module
24-10
Freescale Semiconductor
PXR40 Microcontroller Reference Manual, Rev. 1
Table 24-5. Message Buffer Code for Rx buffers
Rx Code
BEFORE
Rx New Frame
Description
Rx Code
AFTER
Rx New Frame
Comment
0000
INACTIVE: MB is not active.
–
MB does not participate in the matching
process.
0100
EMPTY: MB is active and
empty.
0010
MB participates in the matching process. When
a frame is received successfully, the code is
automatically updated to FULL.
0010
FULL: MB is full.
0010
The act of reading the C/S word followed by
unlocking the MB does not make the code
return to EMPTY. It remains FULL. If a new
frame is written to the MB after the C/S word
was read and the MB was unlocked, the code
still remains FULL.
0110
If the MB is FULL and a new frame is
overwritten to this MB before the CPU had time
to read it, the code is automatically updated to
OVERRUN. Refer to
for details about overrun behavior.
0110
OVERRUN: a frame was
overwritten into a full buffer.
0010
If the code indicates OVERRUN but the CPU
reads the C/S word and then unlocks the MB,
when a new frame is written to the MB the code
returns to FULL.
0110
If the code already indicates OVERRUN, and
yet another new frame must be written, the MB
will be overwritten again, and the code will
remain OVERRUN. Refer to
for details about overrun
behavior.
0XY1
1
NOTES:
1
Note that for Tx MBs (see
), the BUSY bit should be ignored upon read, except when AEN bit is set
in the FLEXCAN_x_MCR register.
BUSY: Flexcan is updating the
contents of the MB. The CPU
must not access the MB.
0010
An EMPTY buffer was written with a new frame
(XY was 01).
0110
A FULL/OVERRUN buffer was overwritten (XY
was 11).
Table 24-6. Message Buffer Code for Tx buffers
RTR
Initial Tx
code
Code after
successful
transmission
Description
X
1000
–
INACTIVE: MB does not participate in the arbitration process.
X
1001
–
ABORT: MB was configured as Tx and CPU aborted the
transmission. This code is only valid when AEN bit in
FLEXCAN_x_MCR is asserted. MB does not participate in the
arbitration process.
0
1100
1000
Transmit data frame unconditionally once. After transmission, the
MB automatically returns to the INACTIVE state.
Summary of Contents for PXR4030
Page 1: ...PXR40 Microcontroller Reference Manual Devices Supported PXR4030 PXR4040 PXR40RM Rev 1 06 2011...
Page 30: ...PXR40 Microcontroller Reference Manual Rev 1 Freescale Semiconductor xxx...
Page 40: ...PXR40 Microcontroller Reference Manual Rev 1 xl Freescale Semiconductor...
Page 66: ...Memory Map PXR40 Microcontroller Reference Manual Rev 1 2 4 Freescale Semiconductor...
Page 120: ...Signal Descriptions 3 54 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Page 860: ...FlexCAN Module 24 50 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Page 1167: ...Decimation Filter Freescale Semiconductor 28 53 PXR40 Microcontroller Reference Manual Rev 1...
Page 1168: ...Decimation Filter 28 54 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
