SAM7X256_14 Datasheet, PDF (532/662 Pages) ATMEL Corporation – ARM-based Flash MCU

36.8.18 CAN Message Data High Register
Name:
CAN_MDHx
Access Type:
Read-write
31
30
29
28
27
26
25
24
MDH
23
22
21
20
19
18
17
16
MDH
15
14
13
12
11
10
9
8
MDH
7
6
5
4
3
2
1
0
MDH
• MDH: Message Data High Value
When MRDY field is set in the CAN_MSRx register, the upper 32 bits of a received message are read or written by the software
application. Otherwise, the MDH value is locked by the CAN controller to send/receive a new message.
In Receive with overwrite, the CAN controller may modify MDH value while the software application reads MDH and MDL regis-
ters. To check that MDH and MDL do not belong to different messages, the application has to check the MMI field in the
CAN_MSRx register. In this mode, the software application must re-read CAN_MDH and CAN_MDL, while the MMI bit in the
CAN_MSRx register is set.
Bytes are received/sent on the bus in the following order:
1. CAN_MDL[7:0]
2. CAN_MDL[15:8]
3. CAN_MDL[23:16]
4. CAN_MDL[31:24]
5. CAN_MDH[7:0]
6. CAN_MDH[15:8]
7. CAN_MDH[23:16]
8. CAN_MDH[31:24]
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
532