DS80C390_00 Datasheet, PDF (128/155 Pages) Dallas Semiconductor – High-Speed Microcontroller User’s Guide Supplement

DS80C390 High-Speed Microcontroller User’s Guide Supplement
CAN MESSAGE CENTER MOVX REGISTER DESCRIPTIONS
CAN Message Center y Arbitration Register 0 (CnMyAR0)
MOVX
Address¹
7
6
5
4
3
2
1
0
xxxxy2h ID28 ID27
ID26
ID25
ID24
ID23
ID22
ID21
CAN Message Center y Arbitration Register 1 (CnMyAR1)
MOVX
Address¹
7
6
5
4
3
2
1
0
xxxxy3h ID20 ID19
ID18
ID17
ID16
ID15
ID14
ID13
CAN Message Center y Arbitration Register 2 (CnMyAR2)
MOVX
Address¹
7
6
5
4
3
2
1
0
xxxxy4h ID12 ID11
ID10
ID9
ID8
ID7
ID6
ID5
CAN Message Center y Arbitration Register 3 (CnMyAR3)
MOVX
Address¹
7
6
5
4
3
2
xxxxy5h ID4
ID3
ID2
ID1
ID0
0
1
0
0
WTOE
ID28-ID0
Bits 2-1
(CnMyAR3 only)
WTOE
Bit 0
(CnMxAR3 only)
CAN Message Center y Arbitration Registers 0-3. These bits form the
arbitration value/identification number for the message center y. When the
message center is configured in a transmit mode, these registers will be the source
of the 29-bit ID message field (when EX/ ST =1) or the 11-bit ID message field
(when EX/ ST =0). When EX/ ST =1, the 29 message ID bits will correspond to
ID28-ID0 as shown above. When EX/ ST =0, the message ID bits 10-0 correspond
to ID28-18 in CnMyAR0 and CnMyAR1.
When configured in a receive mode, these registers serve as the arbitration value
for message center y, against which incoming messages are compared to ascertain
if they are valid for that message center. When EX/ST =1, all 29 bits of the
arbitration are used, but when EX/ST =0, only the most significant 11 bits are
used.
Reserved – Bits 2 and 1 of the CnMyAR3 register are not used in arbitration. A
read of these bits will always return 0, and writes to these bits will be ignored.
Write-over Enable. This bit controls the ability of a new message to overwrite
an existing message in the corresponding message center in receive mode. The
DTUP and EXTRQ bits for the message center in question must also be
considered to determine the effect of this bit as shown below. The WTOE bit can
only be programmed when the SWINT bit is set.
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