194 JVL A/S - User Manual - Integrated Servo Motors MAC050 - 4500
5.6 Expansion Mod. MAC00-FC2/FC4/FC41
5.6.17 MacTalk CAN debug window
The hardware CAN Node chip have a Node Control Register, this controls the initiali-
zation, defines the node specific interrupt handling and selects an operation mode. The
Node Control Register have a field call LEC (Last Error Code), this bit field indicates if
the latest CAN message has been correct (No error) or it indicates the type of error,
which has been detected.
The register contains the following fields:
Where:
Table for last Error code
Bit 15-8 7 6 5 4 3 2 1 0
Field
0 BOFF EWRN 0 RXOK TXOK LEC
Read
X X X X X X
Write
X X X
Field Meaning Value Description
LEC Last Error Code See table below
TXOK Message Transmit-
ted Successfully
0 No successful transmission since last flag reset
1 A message has been transmitted successfully (error free
and acknowledged by at least one other node)
RXOK Message Received
Successfully
0 No successful reception since last flag reset.
1 A message has been received successfully.
EWRN
Error Warning Status
0 No warning limit exceeded.
1 One of the error counters in the Error Management Logic
reached the error warning limit of 96
BOFF Bus-Off Status
0 CAN controller is not in the bus-off state.
1 CAN controller is in the bus-off state
LEC Meaning Description
000 No error The latest transfer on the CAN bus has been completed successfully
001 Stuff error
More than 5 equal bits in a sequence have occurred in a part of a received
message where this is not allowed
010 Form error A fixed format part of a received frame has the wrong format
011 Ack error The transmitted message was not acknowledged by another node
100 Bit1 error During a message transmission the CAN node tried to send a recessive level
(1), but the monitored bus value was dominant (outside the arbitration field
and the acknowledge slot)
101 Bit0 error Two different conditions are signaledby this code:
1. During transmission of a message (or acknowledge bit, active error flag,
overload flag), the CAN node tried to send a dominant level (0), but the mon
-
itored bus value has been recessive.
2. During bus-off recovery, this code is set each time a sequence of 11 reces-
sive bits has been monitored. The CPU may use this code as an indication,
that the bus is not continuously disturbed
110 CRC error The CRC check sum of the received message was incorrect
111 Reserved
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