CAN Control Registers
1551
SPRUH22I – April 2012 – Revised November 2019
Copyright © 2012–2019, Texas Instruments Incorporated
M3 Controller Area Network (CAN)
Table 23-10. Test Register Field Descriptions (continued)
Bit
Field
Value
Description
2-0
Reserved
Reserved
For all test modes, the Test bit in CAN Control register needs to be set to one. If Test bit is set, the EXL,
Tx1, Tx0, LBack and Silent bits are writable. Bit Rx monitors the state of pin CAN_RX and therefore is
only readable. All Test register functions are disabled when the Test bit is cleared.
NOTE:
The Test register is only writable if Test bit in CAN Control register is set.
NOTE:
Setting Tx[1:0] other than '00' will disturb message transfer.
NOTE:
When the internal loopback mode is active (bit LBack is set), bit EXL will be ignored.
23.15.7 Parity Error Code Register (CAN PERR)
The Parity Error Code register (CAN PERR) is shown and described in the figure and table below.
Figure 23-25. Parity Error Code Register (CAN PERR) [offset = 0x1C]
31
16
Reserved
R-0
15
11
10
8
7
0
Reserved
Word Number
Message Number
R-0
R-U
R-U
LEGEND: R = Read; -
n
= value after reset; -U = Undefined
Table 23-11. Parity Error Code Register Field Descriptions
Bit
Field
Value
Description
31-11
Reserved
Reserved
10-8
Word Number
0x01-0x05
Word number where parity error has been detected RDA word number (1 to 5) of the
message object (according to the Message RAM representation in RDA mode, see
7-0
Message Number
0x01-0x80
Message object number where parity error has been detected
If a parity error is detected, the PER flag will be set in the Error and Status Register. This bit is not reset
by the parity check mechanism; it must be reset by reading the Error and Status Register. In addition to
the PER flag, the Parity Error Code Register will indicate the memory area where the parity error has been
detected (message number and word number).
If more than one word with a parity error was detected, the highest word number with a parity error will be
displayed.
After a parity error has been detected, the register will hold the last error code until power is removed.
23.15.8 Auto-Bus-On Time Register (CAN ABOTR)
The Auto-Bus-On Time register (CAN ABOTR) is shown and described in the figure and table below.