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XC161 Derivatives
Peripheral Units (Vol. 2 of 2)
TwinCAN Module
User’s Manual
21-69
V2.2, 2004-01
TwinCAN_X1, V2.1
MSGVAL
1)
[7:6]
Low
rwh
Message Object Valid
The CAN controller only operates on valid message
objects. Message objects can be tagged invalid while
they are changed or if they are not used at all.
01
Message object is invalid.
10
Message object is valid.
NEWDAT
2)
[9:8]
Low
rwh
New Message Object Data Available
01
No update of message object data occurred.
10
New message object data has been updated.
MSGLST
[11:10]
Low
rwh
Message Lost (for reception only)
01
No message object data is lost.
10
The CAN controller has stored a new message
into the message object while NEWDAT was
still set. The previously stored message is lost.
MSGLST must be reset by software.
CPUUPD
3)
[11:10]
Low
rwh
CPU Update (for transmission only)
Indicates that the corresponding message object can
not be transmitted now. The software sets this bit in
order to inhibit the transmission of a message that is
currently updated by the CPU or to control the
automatic response to remote requests.
01
The message object data can be transmitted
automatically by the CAN controller.
10
The automatic transmission of the message
data is inhibited.
TXRQ
4)
[13:12]
Low
rwh
Message Object Transmit Request Flag
01
No message object data transmission is
requested by the CPU or a remote frame.
10
The transmission of the message object data,
requested by the CPU or by a remote frame, is
pending.
Automatic setting of TXRQ by the CAN node
controller can be disabled for Gateway Message
Objects via control bit GDFS = ‘0’.
TXRQ is automatically reset, when the message
object has been successfully transmitted.
If there are several valid message objects with
pending transmit requests, the message object with
the lowest message number will be transmitted first.
Field
Bits
Type
Description