MC68HC12 Datasheet, PDF (349/478 Pages) Motorola, Inc – The MC68HC912DT128A microcontroller unit (MCU) is a 16-bit device composed of standard on-chip peripherals including a 16-bit central processing unit

MSCAN Controller
Programmer’s Model of Message Storage
RTR — Remote transmission request
This flag reflects the status of the Remote Transmission Request bit
in the CAN frame. In case of a receive buffer it indicates the status of
the received frame and allows to support the transmission of an
answering frame in software. In case of a transmit buffer this flag
defines the setting of the RTR bit to be sent.
0 = Data frame
1 = Remote frame
18.12.3 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. At transmission of a remote frame, the
data length code is transmitted as programmed while the number of
transmitted bytes is always 0. The data byte count ranges from 0 to 8
for a data frame. Table 18-3 shows the effect of setting the DLC bits.
Table 18-3. Data length codes
Data length code
DLC3 DLC2 DLC1 DLC0
0
0
0
0
0
0
0
1
0
0
1
0
0
0
1
1
0
1
0
0
0
1
0
1
0
1
1
0
0
1
1
1
1
0
0
0
Data
byte
count
0
1
2
3
4
5
6
7
8
MC68HC912DT128A — Rev 4.0
MOTOROLA
MSCAN Controller
Technical Data
349