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The intent of the protocol is to allow hand typing of commands from a terminal except for
long commands like flash page write that would only be done using the FastVision camera
control GUI.
Response Protocol
Each command signals completion by sending the command character G-Z (always
uppercased) followed by any command-specific response and terminated with a non-
escaped carriage-return, hex 0d. For commands that respond with binary data, the
carriage-return (0d) and backslash (5c) are escaped as in the command protocol.
If a command cannot be completed for any reason the response will be the character? (3F)
and possibly a numeric error code, followed by a carriage-return to indicate negative
acknowledge.
Here again the intent is to use ASCII only response except for long data sequences like
flash page read.
Synchronization
The ASCII format of most commands combined with the escaped carriage-return in binary
commands allows simple resynchronization after errors. Sending two carriage-returns will
always reset the serial link to its default state, waiting for new command.
In addition, when the serial logic detects a framing error or protocol error, it will go into an
idle state until the next non-escaped carriage-return. During the idle state any serial data
is ignored. Any carriage-return which follows the idle state causes the negative
acknowledge sequence to be sent.
Timeout
If the serial logic is in a state waiting for a command to be completed and no input is
detected for 5 seconds, it will reset to waiting for a new command state without sending
any response. This would typically happen after the serial link had noise from attaching or
restarting the frame grabber.
Command Forwarding
All commands are forwarded to the data FPGA. All responses from the data FPGA are
forwarded to the host. Starting commands on both the Control and Data FPGAs without
waiting for completion may cause interleaving of response codes.
Command Set Overview
