Data Register (Dtr) - Fujitsu MB90895 Series Hardware Manual

CHAPTER 16 CAN controller
16.3.23

Data Register (DTR)

Data register (DTR) for message buffer. The data register (DTR) sets the messages at
transmitting or receiving a data frame.The data length can be set from 0 to 8 bytes.
I Data Register (DTR)
BYTE0
BYTE7
X :Undefined
R/W :Read/Write
Table 16.3-25 Functions of Data Register (DTR)
bit0
:
:
:
bit15
532
Figure 16.3-30 Data Register (DTR)
bit 7 6 5
D7 D6 D5
R/W R/W R/W
bit 15 14 13
D7 D6 D5
R/W R/W R/W
Bit name
D7 to 0 (BYTE7 to 0) :
•
Data bit 7 to 0
•
•
•
Note:
4 3 2 1
D4 D3 D2 D1
R/W R/W R/W R/W
12 11 10 9
D4 D3 D2 D1
R/W R/W R/W R/W
Function
The data register (DTRx) is used only for transmitting or
receiving a data frame.
The transmit message is set up to 8 bytes. The received mes-
sage is stored on an MSB-first basis starting with the small
message buffer number (BYTE0 to BYTE7).
The received message is stored. The received message is
stored on an MSB-first basis starting with the small message
buffer number (BYTE0 to BYTE7).
If the received message is less than 8 bytes, undefined data is
stored in the rest of the bytes of the data register (DTRx).
However this does not affect the operation.
When setting the data register (DTR), write by words.
Writing by bytes is disabled.
0 Reset value
D0
X X X X X X X X
B
R/W
8 Reset value
D0
X X X X X X X X
B
R/W