BAT32G1x9 user manual | Chapter 22 CAN control
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Rev.1.02
22.7.18
CAN module send History List Register (CnTGPT).
The CnTGPT register is used to read out the list of transmission histories.
Figure 22-43. CAN
module sends history list register format
(CnTGPT) (1/2).
(a) read
(b) write
(a) read
TGPT7-TGPT0
Sends a history list read pointer
0 to
15
When the CnTGPT register is read, the contents of the read pointer (TGPT) index
element of the send history list are read. These indicate the number of message buffers
to which the data frame or remote frame was last transmitted
THPM
1
Transmit History PointerMatch
0
The send history list has at least one packet buffer number that has not yet been read
1
Sends a history list to no packet buffer number that has not yet been read
1 When the THPM is 1, the reading values of TGPT0 to TGPT7 are invalid
TOVF
Send history list overflow bit
0
All packet buffer numbers that have not yet been read are retained. All numbers of the
message buffer to which the new data frame or remote frame is transmitted are recorded
to the transmission history list (the transmission history list has an empty element).
1
At least 7 entries (i.e., read CnTGPT) have been stored since the host processor last
served THL. The first 6 entries are stored sequentially, and the last entry can be
overwritten whenever a new packet is transmitted, because when the TOVF bit is set, all
buffer numbers are stored in the LOPT-1 position. Therefore, the transfer sequence
cannot now be fully recovered.
1. If TOVF is set, THPM is no longer cleared during message transmission, but if the
software reads all entries of CTGPT, THPM is still set.
Note: In normal operating mode with ABT, the transmission history of packet buffer 0
to 7 is not put into the list
Figure22-43. CAN
module sends history list register format
(CnTGPT) (2/2).
(b) write
ClearTOVF
Set the TOVF
bit
0
TOVF has not changed
1
TOVF clear
0