CAN232 FD User Manual
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was starting. To ensure the SYNC sequence does not occur in the middle of the message, the transmitter
must scan the message for the binary value $FF and replace it with the 2-byte DATA sequence $FF $01.
The $01 byte is the stuff byte. Now if a ..$FF $00.. pair occurs inside the message then it will be translated
into $FF $01 $00 by the byte stuffing. The receiver must convert the DLE DATA sequence back to a single
byte $FF by removing the $01 byte.
The following table defines all the valid DLE sequences implemented in the protocol. Any other DLE
sequence received should be considered an error and will cause the message to be discarded.
DLE Sequences Defined
Name
Byte-0
Byte-1
Type
Comment
SYNC
$FF
$00
FRAME
Marks start of message
DATA
$FF
$01
DATA
Defines data value of $FF
CONFIG
$FF
$02
COMMAND
Configuration mode entry command
REPORT
$FF
$03
STATUS
Report CAN error status change
DLE RE-SYNC
$FF
$FF
ERROR
Restarts DLE sequence parsing
After the DLE SYNC sequence to start the message, a CAN message header format is defined, followed by
the CAN data values. Note any of the header or data bytes might contain the $FF value and must be scanned
to perform the byte stuffing.
Summary of Contents for CAN232 FD
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