DCAN Registers
Table 23-46. IF1CMD Register Field Descriptions (continued)
Bit
Field
Type
Reset
Description
20
Control
R/WP
0h
Access control bits.
If the TxRqst/NewDat bit in this register(Bit [18]) is set, the TxRqst/
NewDat bit in the IF1 message control register will be ignored.
0x0 = Control bits will not be changed
0x1 = Direction = Read: The message control bits will be transferred
from the message object addressed by message number (Bits [7:0])
to the IF1 register set. Direction = Write: The message control bits
will be transferred from the IF1 register set to the message object
addressed by message number (Bits [7:0]).
19
ClrIntPnd
R/WP
0h
Clear interrupt pending bit
0x0 = IntPnd bit will not be changed
0x1 = Direction = Read: Clears IntPnd bit in the message object.
Direction = Write: This bit is ignored. Copying of IntPnd flag from IF1
Registers to message RAM can only be controlled by the control flag
(Bit [20]).
18
TxRqst/NewDat
R/WP
0h
Access transmission request bit.
Note: If a CAN transmission is requested by setting TxRqst/NewDat
in this register, the TxRqst/NewDat bits in the message object will be
set to one independent of the values in IF1 message control
Register.
Note: A read access to a message object can be combined with the
reset of the control bits IntPnd and NewDat.
The values of these bits transferred to the IF1 message control
register always reflect the status before resetting them.
0x0 = Direction = Read: NewDat bit will not be changed. Direction =
Write: TxRqst/NewDat bit will be handled according to the control bit.
0x1 = Direction = Read: Clears NewDat bit in the message object.
Direction = Write: Sets TxRqst/NewDat in message object.
17
Data_A
R/WP
0h
Access Data Bytes 0 to 3.
0x0 = Data Bytes 0-3 will not be changed.
0x1 = Direction = Read: The data bytes 0-3 will be transferred from
the message object addressed by the Message Number (Bits [7:0])
to the corresponding IF1 register set. Direction = Write: The data
bytes 0-3 will be transferred from the IF1 register set to the message
object addressed by the Message Number (Bits [7:0]). Note: The
duration of the message transfer is independent of the number of
bytes to be transferred.
16
Data_B
R/WP
0h
Access Data Bytes 4 to 7.
0x0 = Data Bytes 4-7 will not be changed.
0x1 = Direction = Read: The data bytes 4-7 will be transferred from
the message object addressed by Message Number (Bits [7:0]) to
the corresponding IF1 register set. Direction = Write: The data bytes
4-7 will be transferred from the IF1 register set to the message
object addressed by message number (Bits [7:0]). Note: The
duration of the message transfer is independent of the number of
bytes to be transferred.
15
Busy
R/WP
0h
Busy flag.
This bit is set to one after the message number has been written to
bits 7 to 0.
IF1 register set will be write protected.
The bit is cleared after read/write action has been finished.
0x0 = No transfer between IF1 register set and message RAM is in
progress.
0x1 = Transfer between IF1 register set and message RAM is in
progress.
3960
Controller Area Network (CAN)
SPRUH73H – October 2011 – Revised April 2013
Copyright © 2011–2013, Texas Instruments Incorporated