Freescale’s Scalable Controller Area Network (S12MSCANV3)
8.3.3.1.1
IDR0–IDR3 for Extended Identifier Mapping
Module Base + 0x00X0
7
6
5
4
3
2
1
0
R
ID28
W
ID27
ID26
ID25
ID24
ID23
ID22
ID21
Reset:
x
x
x
x
x
x
x
x
Figure 8-26. Identifier Register 0 (IDR0) — Extended Identifier Mapping
Table 8-27. IDR0 Register Field Descriptions — Extended
Description
Field
7-0
ID[28:21]
Extended Format Identifier — The identifiers consist of 29 bits (ID[28:0]) for the extended format. ID28 is the
most significant bit and is transmitted first on the CAN bus during the arbitration procedure. The priority of an
identifier is defined to be highest for the smallest binary number.
Module Base + 0x00X1
7
6
5
4
3
2
1
0
R
ID20
W
ID19
ID18
SRR (=1)
IDE (=1)
ID17
ID16
ID15
Reset:
x
x
x
x
x
x
x
x
Figure 8-27. Identifier Register 1 (IDR1) — Extended Identifier Mapping
Table 8-28. IDR1 Register Field Descriptions — Extended
Description
Field
7-5
ID[20:18]
Extended Format Identifier — The identifiers consist of 29 bits (ID[28:0]) for the extended format. ID28 is the
most significant bit and is transmitted first on the CAN bus during the arbitration procedure. The priority of an
identifier is defined to be highest for the smallest binary number.
4
Substitute Remote Request — This fixed recessive bit is used only in extended format. It must be set to 1 by
SRR
the user for transmission buffers and is stored as received on the CAN bus for receive buffers.
3
IDE
ID Extended — This flag indicates whether the extended or standard identifier format is applied in this buffer. In
the case of a receive buffer, the flag is set as received and indicates to the CPU how to process the buffer
identifier registers. In the case of a transmit buffer, the flag indicates to the MSCAN what type of identifier to send.
0 Standard format (11 bit)
1 Extended format (29 bit)
2-0
ID[17:15]
Extended Format Identifier — The identifiers consist of 29 bits (ID[28:0]) for the extended format. ID28 is the
most significant bit and is transmitted first on the CAN bus during the arbitration procedure. The priority of an
identifier is defined to be highest for the smallest binary number.
S12P-Family Reference Manual, Rev. 1.13
Freescale Semiconductor
279
FREESCALE [ Freescale ]
