Datasheet

Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
MC9S12XDP512 Data Sheet, Rev. 2.21
454 Freescale Semiconductor
10.3.3.3 Data Length Register (DLR)
This register keeps the data length field of the CAN frame.
Module Base + 0x0004 (DSR0)
0x0005 (DSR1)
0x0006 (DSR2)
0x0007 (DSR3)
0x0008 (DSR4)
0x0009 (DSR5)
0x000A (DSR6)
0x000B (DSR7)
76543210
R
DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
W
Reset: xxxxxxxx
Figure 10-34. Data Segment Registers (DSR0–DSR7) — Extended Identifier Mapping
Table 10-31. DSR0–DSR7 Register Field Descriptions
Field Description
7:0
DB[7:0]
Data bits 7:0
76543210
R
DLC3 DLC2 DLC1 DLC0
W
Reset: xxxxxxxx
= Unused; always read “x”
Figure 10-35. Data Length Register (DLR) — Extended Identifier Mapping
Table 10-32. DLR Register Field Descriptions
Field Description
3:0
DLC[3:0]
Data Length Code Bits — The data length code contains the number of bytes (data byte count) of the respective
message. During the transmission of a remote frame, the data length code is transmitted as programmed while
the number of transmitted data bytes is always 0. The data byte count ranges from 0 to 8 for a data frame.
Table 10-33 shows the effect of setting the DLC bits.