Bafang display protocol implementation, polling for display

[davejupp]

Possibly not the best place to ask this but I've been looking to make a replacement faast (android display) tool that worked with open source bbs-fs (and was open source itself).

I've looked through a few bits of code implementing the bafang display protocol, and as far as I can tell it just polls the controller for all the details it needs constantly. I haven't been able to see any obvious differences in polling rate or anything for a specific reply (and I have seen that it looks like some request/reply pairs are repeated consistent numbers of times, but I'm not sure if that's a artifact of trying to reverse engineer the protocol.

Anyhow, does anyone have any good idea/docs on how I should (presumably) poll the bafang controller, e.g.

1. how often (once per 100ms seems usual?)
2. do different requests have different priorities? (does priority even matter if we're just asking for all the details every time?)
3. it seems worth optimizing the numbers of calls I do to the controller but is this essential or even helpful?
4. anything I should beware of so I don't accidentally do something horribly dangerous to myself?

Anyone who has any info actually implementing this display protocol and has any advice would be welcome. Or some links to discussions. I have access to the luna and some other display code but it's quite un-commented so it's unclear what it's doing inplaces.

I'm sure I can work it out from slogging through the existing source but it's not super clear to me so any clarificiations/info/implementation details would be helpful.

Thanks all!

[davejupp]

Also I've been currently sending a request and awaiting a response (or several responses until it replies to my next request) I don't think you can send requests and then receive replies out of sync via uart/serial but it'd be nice if someone could confirm that.

[aalm]

Yes, it is request/response, and only one at a time, so as a display you must act accordingly.

iirc. i picked some values for the polling loop based on maybe comments in extcom.c, but
then you should also consider whether or not you want the display to handle being ran w/
eventlog enabled too(mine does).

[davejupp]

Awesome, thanks for the confirmation. Just wanted to confirm I hadn't horribly misread any of this code before finalizing some kind of implementation.

Thanks!