CP3BT23_14 Datasheet, PDF (163/324 Pages) Texas Instruments – CP3BT23 Reprogrammable Connectivity Processor with Bluetooth and Dual CAN Interfaces

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EBID
CP3BT23
SNOSCX3A – JULY 2013 – REVISED JANUARY 2014
Table 18-20. Error Field Identifier (continued)
EFID3:0
1011
1100
1101
1110
1111
Field
EXTENDED ARBITRATION
R1/R0
DLC
DATA
CRC
The Error Bit Identifier field reports the bit position of the incorrect bit within the erroneous
frame field. The bit number starts with the value equal to the respective frame field length
minus one at the beginning of each field and is decremented with each CAN bit. Figure 18-
30 shows an example on how the EBID is calculated.
rrrrrr
Incorrect
Bit
Data Field
DS047
Figure 18-30. EBID Example
For example, assume the EFID field shows 1110b and the EBID field shows 111001b. This means the
faulty field was the data field. To calculate the bit position of the error, the DLC of the message needs to
be known. For example, for a DLC of 8 data bytes, the bit counter starts with the value: (8 × 8) 1 = 63; so
when EBID[5:0] = 111001b = 57, then the bit number was 63 57 = 6.
TXE
STUFF
CRC
MON
DRIVE
For example, assume the EFID field shows 1110b and the EBID field shows 111001b. This
means the faulty field was the data field. To calculate the bit position of the error, the DLC of
the message needs to be known. For example, for a DLC of 8 data bytes, the bit counter
starts with the value: (8 × 8) 1 = 63; so when EBID[5:0] = 111001b = 57, then the bit number
was 63 57 = 6.
The Transmit Error bit indicates whether the CAN module was an active transmitter at the
time the error occurred.
0 – The CAN module was a receiver at the time the error occurred.
1 – The CAN module was an active transmitter at the time the error occurred.
The Stuff Error bit indicates whether the bit stuffing rule was violated at the time the error
occurred. Note that certain bit fields do not use bit stuffing and therefore this bit may be
ignored for those fields.
0 – No bit stuffing error.
1 – The bit stuffing rule was violated at the time the error occurred.
The CRC Error bit indicates whether the CRC is invalid. This bit should only be checked if
the EFID field shows the code of the ACK field.
0 – No CRC error occurred.
1 – CRC error occurred.
The Monitor bit shows the bus value on the CANRX pin as sampled by the CAN module at
the time of the error.
The Drive bit shows the output value on the CANTX pin at the time of the error. Note that a
receiver will not drive the bus except during ACK and during an active error flag.
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