[chirp_devel] Kenwood TH-D74A MCP mode is proving to be a pain

[Eric A. Cottrell]

On 12/7/2017 2:40 PM, Eric Wolak via chirp_devel wrote:
> Hello fellow CHIRP contributors,
>
> I'm working on CHIRP support for the Kenwood TH-D74A, and it's turning
> out to be far more difficult than I expected. The memory layout is
> straightforward enough, but the serial protocol seems to have some
> quirks to it. I'm pretty sure my code is having the same exchange as
> the Kenwood MCP software is with the radio, but when CHIRP uploads to
> the radio it glitches at page 1280 and the radio factory resets. It
> also sometimes glitches at the beginning of the upload, though I
> haven't been able to isolate and reproduce that yet.
>
> Does anybody have ideas for what I might be missing here, or what I
> should investigate? I'm reduced at this point to writing a tool that
> replays sessions recorded using Device Monitoring Studio (and the
> replay works), and then diffing it against what CHIRP is doing. Is
> there some more well-trodden path for doing this sort of protocol
> comparison?
>
>
>
Hello,

Some more observations...

I was able to fix the exception problem by adding a close function to 
the proxy class.

I still had some problems going into program mode. It appears the baud 
rate can shift. I noticed the TH-D72 code has a baud detect function 
which is commented out in the TH-D74 sync_in function and missing in the 
TH-D74 sync_out function. I added the calls to the two functions and can 
go into programing mode more consistently.

I find it interesting that the download function between TH-D74 and 
TH-D72 classes are basically the same, but the upload functions are 
different. The TH-D74 upload function does not set the baudrate and RTS 
is set in a different place. This could cause communications problems. 
It also appears some of the actions in the TH-D74 upload function may be 
to correct problems caused by using a different sequence.

Empty memory locations are showing as error in the memory grid and the 
log show various errors.

73 Eric