mcf51ac256a Freescale Semiconductor, Inc, mcf51ac256a Datasheet - Page 344

• Manufacturer Part Number: mcf51ac256a
• Description: Mcf51ac Flexis
• Manufacturer: Freescale Semiconductor, Inc

Freescale’s Controller Area Network (MSCANV1)
15.4.3
The eight data segment registers, each with bits DB[7:0], contain the data to be transmitted or received.
The number of bytes to be transmitted or received is determined by the data length code in the
corresponding DLR register.
15.4.4
This register keeps the data length field of the CAN frame.
15-28
DLC[3:0]
DB[7:0]
Field
Field
7:0
3:0
Reset:
Reset:
W
R
W
Figure 15-32. Data Segment Registers (DSR0–DSR7) — Extended Identifier Mapping
R
Data Segment Registers (DSR0-7)
Data Length Register (DLR)
Data bits 7:0
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 15-33
Figure 15-33. Data Length Register (DLR) — Extended Identifier Mapping
x
7
DB7
7
x
MCF51AC256 ColdFire Integrated Microcontroller Reference Manual, Rev. 5
shows the effect of setting the DLC bits.
= Unused; always read “x”
Table 15-31. DSR0–DSR7 Register Field Descriptions
6
x
DB6
6
x
Table 15-32. DLR Register Field Descriptions
DB5
5
x
5
x
4
x
DB4
Description
Description
4
x
DLC3
DB3
3
x
x
3
DLC2
2
x
DB2
2
x
Freescale Semiconductor
DLC1
1
x
DB1
x
1
DLC0
0
x
DB0
0
x