Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
MC9S12XDP512 Data Sheet, Rev. 2.17
Freescale Semiconductor
451
Table 10-25. IDR0 Register Field Descriptions — Extended
Field
Description
7:0
ID[28:21]
Extended Format Identier — The identiers consist of 29 bits (ID[28:0]) for the extended format. ID28 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.
76543210
R
ID20
ID19
ID18
SRR (=1)
IDE (=1)
ID17
ID16
ID15
W
Reset:
xxxxxxxx
Figure 10-27. Identier Register 1 (IDR1) — Extended Identier Mapping
Table 10-26. IDR1 Register Field Descriptions — Extended
Field
Description
7:5
ID[20:18]
Extended Format Identier — The identiers consist of 29 bits (ID[28:0]) for the extended format. ID28 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.
4
SRR
Substitute Remote Request — This xed recessive bit is used only in extended format. It must be set to 1 by
the user for transmission buffers and is stored as received on the CAN bus for receive buffers.
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)
2:0
ID[17:15]
Extended Format Identier — The identiers consist of 29 bits (ID[28:0]) for the extended format. ID28 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.
76543210
R
ID14
ID13
ID12
ID11
ID10
ID9
ID8
ID7
W
Reset:
xxxxxxxx
Figure 10-28. Identier Register 2 (IDR2) — Extended Identier Mapping
Table 10-27. IDR2 Register Field Descriptions — Extended
Field
Description
7:0
ID[14:7]
Extended Format Identier — The identiers consist of 29 bits (ID[28:0]) for the extended format. ID28 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.