Freescale’s Scalable Controller Area Network (S12MSCANV3)
8.3.3.1.2
IDR0–IDR3 for Standard Identifier Mapping
Module Base + 0x00X0
7
6
5
4
3
2
1
0
R
ID10
W
ID9
ID8
ID7
ID6
ID5
ID4
ID3
Reset:
x
x
x
x
x
x
x
x
Figure 8-30. Identifier Register 0 — Standard Mapping
Table 8-31. IDR0 Register Field Descriptions — Standard
Description
Field
7-0
ID[10:3]
Standard Format Identifier — The identifiers consist of 11 bits (ID[10:0]) for the standard format. ID10 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. See also ID bits in Table 8-32.
Module Base + 0x00X1
7
6
5
4
3
2
1
0
R
ID2
W
ID1
ID0
RTR
IDE (=0)
Reset:
x
x
x
x
x
x
x
x
= Unused; always read ‘x’
Figure 8-31. Identifier Register 1 — Standard Mapping
Table 8-32. IDR1 Register Field Descriptions
Description
Field
7-5
ID[2:0]
Standard Format Identifier — The identifiers consist of 11 bits (ID[10:0]) for the standard format. ID10 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. See also ID bits in Table 8-31.
4
Remote Transmission Request — This flag reflects the status of the Remote Transmission Request bit in the
RTR
CAN frame. In the case of a receive buffer, it indicates the status of the received frame and supports the
transmission of an answering frame in software. In the case of a transmit buffer, this flag defines the setting of
the RTR bit to be sent.
0 Data frame
1 Remote frame
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)
S12P-Family Reference Manual, Rev. 1.13
Freescale Semiconductor
281
FREESCALE [ Freescale ]
