Datasheet
UM10398 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2014. All rights reserved.
User manual Rev. 12.3 — 10 June 2014 292 of 547
NXP Semiconductors
UM10398
Chapter 16: LPC111x/LPC11Cxx C_CAN controller
16.6.1.7 CAN baud rate prescaler extension register
16.6.2 Message interface registers
There are two sets of interface registers which are used to control the CPU access to the
Message RAM. The interface registers avoid conflicts between CPU access to the
Message RAM and CAN message reception and transmission by buffering the data to be
transferred. A complete Message Object (see Section 16.6.2.1
) or parts of the Message
Object may be transferred between the Message RAM and the IFx Message Buffer
registers in one single transfer.
The function of the two interface register sets is identical (except for test mode Basic).
One set of registers may be used for data transfer to the Message RAM while the other
set of registers may be used for the data transfer from the Message RAM, allowing both
processes to be interrupted by each other.
6:5 TX Control of CAN_TXD pins 00 R/W
0x0 Controller. Level at the CAN_TXD pin is
controlled by the CAN controller. This is the
value at reset.
0x1 Sample point. The sample point can be
monitored at the CAN_TXD pin.
0x2 Low. CAN_TXD pin is driven LOW/dominant.
0x3 High. CAN_TXD pin is driven
HIGH/recessive.
7 RX Monitors the actual value of the CAN_RXD
pin.
0R
0 Recessive. The CAN bus is recessive
(CAN_RXD = 1).
1 Dominant. The CAN bus is dominant
(CAN_RXD = 0).
31:8 - R/W -
Table 251. CAN test register (CANTEST, address 0x4005 0014) bit description
Bit Symbol Value Description Reset
value
Access
Table 252. CAN baud rate prescaler extension register (CANBRPE, address 0x4005 0018) bit
description
Bit Symbol Description Reset
value
Access
3:0 BRPE Baud rate prescaler extension
By programming BRPE the Baud Rate Prescaler can be
extended to values up to 1023. Hardware interprets the
value as the value of BRPE (MSBs) and BRP (LSBs) plus
one. Allowed values are 0 to 15.
0x0000 R/W
31:4 - Reserved - -