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Controller area network (bxCAN) RM0008

662/1096 Doc ID 13902 Rev 12

CAN mailbox data length control and time stamp register (CAN_TDTxR)

(x=0..2)

All bits of this register are write protected when the mailbox is not in empty state.

Address offsets: 0x184, 0x194, 0x1A4

Reset value: undefined

31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16

TIME[15:0]

rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw

1514131211109876543210

Reserved

TGT

Reserved

DLC[3:0]

rw rw rw rw rw

Bits 31:16 TIME[15:0]: Message time stamp

This field contains the 16-bit timer value captured at the SOF transmission.

Bits 15:9 Reserved

Bit 8 TGT

: Transmit global time

This bit is active only when the hardware is in the Time Trigger Communication mode, TTCM

bit of the CAN_MCR register is set.

0: Time stamp TIME[15:0] is not sent.

1: Time stamp TIME[15:0] value is sent in the last two data bytes of the 8-byte message:

TIME[7:0] in data byte 7 and TIME[15:8] in data byte 6, replacing the data written in

CAN_TDHxR[31:16] register (DATA6[7:0] and DATA7[7:0]). DLC must be programmed as 8

in order these two bytes to be sent over the CAN bus.

Bits 7:4 Reserved

Bits 3:0 DLC[3:0]: Data length code

This field defines the number of data bytes a data frame contains or a remote frame request.

A message can contain from 0 to 8 data bytes, depending on the value in the DLC field.

ST STM32F101xx User Manual

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