DESIGN OF A CUSTOM ASIC INCORPORATING CAN™ AND 1 ...
DESIGN OF A CUSTOM ASIC INCORPORATING CAN™ AND 1 ...
DESIGN OF A CUSTOM ASIC INCORPORATING CAN™ AND 1 ...
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Table 3.3 Types of Errors [19].<br />
Type of Error Content of Error Target Frame (field) in which errors detected Unit by which<br />
errors<br />
Bit Error This error is detected when<br />
the output level and the data<br />
level on the bus do not match<br />
when they are compared.<br />
Form Error This error is detected when an<br />
illegal format is found in any<br />
fixed-format bit field.<br />
CRC Error This error is detected if the<br />
CRC calculated from the<br />
received message and the<br />
value of the received CRC<br />
sequence do not match.<br />
ACK Error This error is detected if the<br />
ACK slot of the transmit unit<br />
is found recessive (i.e., the<br />
error that is detected when<br />
ACK is not returned from the<br />
Stuffing<br />
Error<br />
receive unit).<br />
This error is detected when<br />
the same level of data is<br />
detected for 6 consecutive<br />
bits in any field that should<br />
have been bit-stuffed.<br />
3.4.1 Output Timing of an Error Frame<br />
Data Frame (S<strong>OF</strong> to E<strong>OF</strong>)<br />
Remote Frame (S<strong>OF</strong> to E<strong>OF</strong>)<br />
Error Frame<br />
Overload Frame<br />
Data Frame (CRC Delimiter, ACK Delimiter,<br />
E<strong>OF</strong>)<br />
Remote Frame (CRC Delimiter, ACK<br />
Delimiter, E<strong>OF</strong>)<br />
Error Delimiter<br />
Overload Delimiter<br />
Data Frame (CRC sequence)<br />
Remote Frame (CRC sequence)<br />
Data Frame (ACK slot)<br />
Remote Frame (ACK slot)<br />
Data Frame (S<strong>OF</strong> to CRC sequence)<br />
Remote Frame (S<strong>OF</strong> to CRC Sequence)<br />
61<br />
detected<br />
Transmit unit<br />
Transmit unit<br />
Receive unit<br />
Receive unit<br />
Transmit unit<br />
Receive unit<br />
The node that detected an error condition outputs an Error Flag to notify other nodes of<br />
the error. The Error Flag output at this time is either an Active-Error Flag or a Passive-Error<br />
Flag depending on the node’s error status. The transmitting node resends the Data or Remote<br />
Frame after it outputs an Error Frame. Table 3.4 shows the timing with which an Error Flag is<br />
output.