
CHAPTER 19 CAN CONTROLLER
Preliminary User’s Manual U17790EJ1V0UD
805
(17) CANn module transmit history list register (CnTGPT)
The CnTGPT register is used to read the transmit history list.
(1/2)
After reset: xx02H
R/W
Address: C0TGPT 03FEC064H, C1TGPT 03FEC664H
(a) Read
15
14
13
12
11
10
9
8
CnTGPT
TGPT7
TGPT6
TGPT5
TGPT4
TGPT3
TGPT2
TGPT1
TGPT0
7
6
5
4
3
2
1
0
THPM
TOVF
(b) Write
15
14
13
12
11
10
9
8
CnTGPT
0
7
6
5
4
3
2
1
0
Clear
TOVF
(a) Read
TGPT7 to TGPT0
Transmit history list read pointer
0 to 31
When the CnTGPT register is read, the contents of the element indexed by the read pointer
(TGPT) of the transmit history list are read. These contents indicate the number of the message
buffer to which a data frame or a remote frame was transmitted last.
THPM
Note
Transmit history pointer match
0
The transmit history list has at least one message buffer number that has not been read.
1
The transmit history list has no message buffer numbers that have not been read.
TOVF
Transmit history list overflow bit
0
All the message buffer numbers that have not been read are preserved. All the numbers of the
message buffers to which a new data frame or remote frame has been transmitted are recorded
to the transmit history list (the transmit history list has a vacant element).
1
At least 7 entries have been stored since the host processor serviced the THL last time (i.e. read
CnTGPT). The first 6 entries are sequentially stored whereas the last entry might have been
overwritten by newly transmitted messages a number of times because all buffer numbers are
stored at position LOPT-1 when TOVF bit is set to 1. As a consequence receptions cannot be
completely recovered in the order that they were received.
Note
The read value of the TGPT0 to TGPT7 bits is invalid when the THPM bit = 1.
Remark
Transmission from message buffers 0 to 7 is not recorded to the transmit history list in the normal
operation mode with ABT.