Datasheet

Freescale’s Scalable Controller Area Network (S12MSCANV3)
MC9S12G Family Reference Manual, Rev.1.23
Freescale Semiconductor 607
18.3.2.18 MSCAN Identifier Mask Registers (CANIDMR0–CANIDMR7)
The identifier mask register specifies which of the corresponding bits in the identifier acceptance register
are relevant for acceptance filtering. To receive standard identifiers in 32 bit filter mode, it is required to
program the last three bits (AM[2:0]) in the mask registers CANIDMR1 and CANIDMR5 to “don’t care.”
To receive standard identifiers in 16 bit filter mode, it is required to program the last three bits (AM[2:0])
in the mask registers CANIDMR1, CANIDMR3, CANIDMR5, and CANIDMR7 to “don’t care.”
Module Base + 0x0010 to Module Base + 0x0013 Access: User read/write
1
1
Read: Anytime
Write: Anytime in initialization mode (INITRQ = 1 and INITAK = 1)
76543210
R
AC7 AC6 AC5 AC4 AC3 AC2 AC1 AC0
W
Reset 00000000
Figure 18-20. MSCAN Identifier Acceptance Registers (First Bank) — CANIDAR0–CANIDAR3
Table 18-22. CANIDAR0–CANIDAR3 Register Field Descriptions
Field Description
7-0
AC[7:0]
Acceptance Code Bits — AC[7:0] comprise a user-defined sequence of bits with which the corresponding bits
of the related identifier register (IDRn) of the receive message buffer are compared. The result of this comparison
is then masked with the corresponding identifier mask register.
Module Base + 0x0018 to Module Base + 0x001B Access: User read/write
1
1
Read: Anytime
Write: Anytime in initialization mode (INITRQ = 1 and INITAK = 1)
76543210
R
AC7 AC6 AC5 AC4 AC3 AC2 AC1 AC0
W
Reset 00000000
Figure 18-21. MSCAN Identifier Acceptance Registers (Second Bank) — CANIDAR4–CANIDAR7
Table 18-23. CANIDAR4–CANIDAR7 Register Field Descriptions
Field Description
7-0
AC[7:0]
Acceptance Code Bits — AC[7:0] comprise a user-defined sequence of bits with which the corresponding bits
of the related identifier register (IDRn) of the receive message buffer are compared. The result of this comparison
is then masked with the corresponding identifier mask register.