00 32 01 00 03
00 33 01 00 00
The low level protocol does things such as attaching control characters and checksums, as well as checking for any transmission errors.
The actual sequence of bytes transmitted is as follows:
|Computer sends:||Camera Sends||Name||Description|
|10 02||-||DLE-STX||Data Link Escape followed by Start of TeXt - this indicates the beginning of a packet of data to be transmitted over the serial link|
|00 32 01 00 03||-||-||This is the actual data that we want to transmit. It is the set flash command described above|
|10 03||-||DLE-ETX||Data Link Escape followed by End of TeXt - this indicates the end of the message|
|33||-||BCC||Block check character - this is a checksum computed by doing an XOR of all the data bytes as well as the final ETX character|
|-||06||ACK||Acknowledge - the camera acknowledges that it has received the command correctly and understood it|
|-||10 02||DLE-STX||Data Link Escape followed by Start of TeXt - this indicates the beginning of the packet of data to be transmitted to the computer|
|-||00 33 01 00 00||-||This is the actual response message sent by the camera|
|-||10 03||DLE-ETX||Data Link Escape followed by End of TeXt - this indicates the end of the message|
|-||30||BCC||Block check character - this is a checksum computed by doing an XOR of all the data bytes as well as the final ETX character|
|06||-||ACK||Acknowledge - we acknowledge receipt of the camera response message|
Note that only the bytes shown in bold are the actual data transmitted. The rest of the bytes are just for controlling the data flow. I.e. they belong to the low level protocol.
In calculating the checksum, the only bytes considered in addition to the bold ones are the ETX control characters at the end of each message.
Page last updated on 2nd June 1999
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