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UM10503
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© NXP B.V. 2015. All rights reserved.
User manual
Rev. 2.1 — 10 December 2015
1247 of 1441
NXP Semiconductors
UM10503
Chapter 45: LPC43xx/LPC43Sxx C_CAN
45.6.2.3 CAN message interface command mask registers
The control bits of the IFx Command Mask Register specify the transfer direction and
select which of the IFx Message Buffer Registers are source or target of the data
transfer.The functions of the register bits depend on the transfer direction (read or write)
which is selected in the WR/RD bit (bit 7) of this Command mask register.
Select the WR/RD to
one
for the Write transfer direction (write to message RAM)
zero
for the Read transfer direction (read from message RAM)
Transfer direction Write
Table 1047.CAN message interface command mask registers write direction
(IF1_CMDMSK_W, address 0x400E 2024 (C_CAN0) and 0x400A 4024 (C_CAN1))
bit description
Bit
Symbol
Value
Description
Reset
value
Access
0
DATA_B
Access data bytes 4-7
0
R/W
0
Data bytes 4-7 unchanged.
1
Transfer data bytes 4-7 to message object.
1
DATA_A
Access data bytes 0-3
0
R/W
0
Data bytes 0-3 unchanged.
1
Transfer data bytes 0-3 to message object.
2
TXRQST
Access transmission request bit
0
R/W
0
No transmission request. TXRQSRT bit
unchanged in IF1/2_MCTRL.
Remark:
If a transmission is requested by
programming this bit, the TXRQST bit in the
CANIFn_MCTRL register is ignored.
1
Request a transmission. Set the TXRQST bit
IF1/2_MCTRL.
3
CLRINTPND
-
This bit is ignored in the write direction.
0
R/W
4
CTRL
Access control bits
0
R/W
0
Control bits unchanged.
1
Transfer control bits to message object
5
ARB
Access arbitration bits
0
R/W
0
Arbitration bits unchanged.
1
Transfer Identifier, DIR, XTD, and MSGVAL
bits to message object.