Datasheet

532
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
36.8.18 CAN Message Data High Register
Name: CAN_MDHx
Access Type: Read-write
• 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]
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
76543210
MDH