So a self-synchronizing variable-length encoding? Something like this:

• 0by0xxxxxx: 6 data bits
• 0by10xxxxx: 5 data bits
• 0by110xxxx: 4 data bits
• 0by1110xxx: 3 data bits
• 0by11110xx: 2 data bits
• 0by111110x: 1 data bit
• 0by1111110: 0 data bits

where y indicates whether this is the initial byte or continuation byte, and a 0 data bit byte indicating the end of the sequence.

It would be nice if DMA (input and output), Analyzer, and DRTIO all three could use the same (or at least very similar) serialization formats.

@whitequark y?

There cannot be a lot in common, except for trivialities (e.g. the order of those few fields that are common), and more importantly for the way the variable length is communicated.

@jordens yes, y.

And the analyzer is the only one that requires the variable length encoding to be self-synchronizing, so it's not clear that even that should be shared.

Well, it is definitely less error-prone to have one variable-length encoder than two, on both sides.