DR
AFT
DR
AFT
DRAFT
DR
D
RAFT
DRAFT
DRA
FT DRAF
D
RAFT DRAFT DRAFT DRAFT DRAFT D
DRAFT
D
RAFT DRA
FT DRAFT DRAFT DRAFT DRA
UM10316_0
© NXP B.V. 2008. All rights reserved.
User manual
Rev. 00.06 — 17 December 2008
319 of 571
NXP Semiconductors
UM10316
Chapter 21: LPC29xx CAN 0/1
9.2 CAN controller command register
The CAN controller command register initiates an action in the transfer layer of the CAN
controller.
The CCCMD register is write-only.
shows the bit assignment of the CCCMD
register.
[1]
On self-reception request a message is transmitted and simultaneously received if the acceptance filter is
set to the corresponding identifier. A receive and a transmit interrupt indicates correct self-reception (see
also the self-test mode (STM) bit in the mode register; see
Table 268. CAN controller command register bit description (CCCMD, address 0xE008 0004
(CAN0) and 0xE008 1004 (CAN1))
Bit
Symbol
Access
Value
Description
31 to 8
reserved
R
-
Reserved; do not modify. Read as logic 0
7
STB3
W
Select transmit buffer 3
1
Transmit buffer 3 is selected for transmission.
6
STB2
W
Select transmit buffer 2
1
Transmit buffer 2 is selected for transmission
5
STB1
W
Select transmit buffer 1
1
Transmit buffer 1 is selected for transmission
4
SRR
W
Self-reception request
1
A message is transmitted from the selected
transmit buffer and received simultaneously.
Transmission and self-reception request has to
be set simultaneously with STB3, STB2 or
STB1
3
CDO
W
Clear data overrun
1
The data-overrun bit in the CAN controller
status register is cleared. This command bit is
used to clear the data-overrun condition
signalled by the data-overrun status bit. As long
as the data-overrun status bit is set no further
data-overrun interrupt is generated
2
W
Release receive buffer
1
The receive buffer, representing the message
memory space in the double receive buffer, is
released
1
AT
W
Abort transmission
1
If not already in progress, a pending
transmission request for the selected transmit
buffer is cancelled. If the abort-transmission
and transmit-request bits are set in the same
write operation, frame transmission is
attempted once. No retransmission is
attempted if an error is flagged or if arbitration
has been lost
0
TR
W
-
Transmission request
1
A message from the selected transmit buffer is
queued for transmission