Chapter 16 Freescale’s Scalable Controller Area Network (S12MSCANV3)
MC9S12XE-Family Reference Manual , Rev. 1.21
634
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16.3.3.1.2
IDR0–IDR3 for Standard Identier Mapping
Module Base + 0x00X0
76543210
R
ID10
ID9
ID8
ID7
ID6
ID5
ID4
ID3
W
Reset:
xxxxxxxx
Figure 16-30. Identier Register 0 — Standard Mapping
Table 16-31. IDR0 Register Field Descriptions — Standard
Field
Description
7-0
ID[10:3]
Standard Format Identier — The identiers consist of 11 bits (ID[10:0]) for the standard format. ID10 is the
most signicant bit and is transmitted rst on the CAN bus during the arbitration procedure. The priority of an
identier is dened to be highest for the smallest binary number. See also ID bits in
Table 16-32.Module Base + 0x00X1
76543210
R
ID2
ID1
ID0
RTR
IDE (=0)
W
Reset:
xxxxxxxx
= Unused; always read ‘x’
Figure 16-31. Identier Register 1 — Standard Mapping
Table 16-32. IDR1 Register Field Descriptions
Field
Description
7-5
ID[2:0]
Standard Format Identier — The identiers consist of 11 bits (ID[10:0]) for the standard format. ID10 is the
most signicant bit and is transmitted rst on the CAN bus during the arbitration procedure. The priority of an
identier is dened to be highest for the smallest binary number. See also ID bits in
Table 16-31.4
RTR
Remote Transmission Request — This ag reects the status of the Remote Transmission Request bit in the
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 ag denes the setting of
the RTR bit to be sent.
0 Data frame
1 Remote frame
3
IDE
ID Extended — This ag indicates whether the extended or standard identier format is applied in this buffer. In
the case of a receive buffer, the ag is set as received and indicates to the CPU how to process the buffer
identier registers. In the case of a transmit buffer, the ag indicates to the MSCAN what type of identier to send.
0 Standard format (11 bit)
1 Extended format (29 bit)