Data Length Register (Dlr); Mscan Transmit Buffer Priority Register (Tbpr)—Mbar + 0X0979 - Freescale Semiconductor MPC5200B User Manual

19.6.3

Data Length Register (DLR)

This register keeps the data length field of the CAN frame.
DLC3 - DLC0 — 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 19-29
DLC3
0
0
0
0
0
0
0
0
1
19.6.4 MSCAN Transmit Buffer Priority Register (TBPR)—MBAR + 0x0979 / 0x09F9
R
W
RESET:
Bit Name
0:7 PRIO[7:0]
Freescale Semiconductor
shows the effect of setting the DLC bits.
Table 19-29. Data Length Codes
Data Length Code
DLC2
0
0
0
0
1
1
1
1
0
Table 19-30. MSCAN Transmit Buffer Priority Register
msb 0 1 2
0 0 0
Register defines local priority of associated message buffer. Local priority is used for
MSCAN internal prioritization process and is defined to be highest for the smallest binary
number. MSCAN implements the following internal prioritization mechanism:
• All transmission buffers with a cleared TXEx flag participate in prioritization
immediately before start of frame (SOF) is sent.
• Transmission buffer with lowest local priority field wins prioritization.
• If more than one buffer has the same lowest priority, message buffer with lower index
number wins.
MPC5200B Users Guide, Rev. 1
Programmer's Model of Message Storage
DLC1 DLC0
0 0
0 1
1 0
1 1
0 0
0 1
1 0
1 1
0 0
3 4 5
0 0 0
Description
Data Byte Count
0
1
2
3
4
5
6
7
8
6 7 lsb
0 0
19-25