Any brave dive computer download testers out there?
sebastien.dugue.subsurface at gmail.com
Thu Apr 19 02:18:51 PDT 2018
Thanks Jef, this may indeed be a good starting point.
On Thu, Apr 19, 2018 at 10:20 AM, Jef Driesen <jef at libdivecomputer.org> wrote:
> On 2018-04-19 09:42, Sébastien Dugué wrote:
>> On Thu, Apr 19, 2018 at 1:50 AM, Linus Torvalds
>> <torvalds at linux-foundation.org> wrote:
>>> On Wed, Apr 18, 2018 at 4:18 PM, Linus Torvalds
>>> <torvalds at linux-foundation.org> wrote:
>>>> Hmm. Which IRDA chip is it that is in the Uwatec dongle?
>>>> Is it perhaps the MosChip MCS7780? You'd know, because then it would
>>>> be using USB ID 9710:7780. That seems to be the common case.
>>> Hmm. Googling around, I see that it might also be the Sigmatel
>>> Stir4200 (USB ID 066F:4210).
>>> That actually has better documentation, and shows exactly the framing
>>> for the normal MIR format (which it would be for the normal 9600
>>> baud). I suspect the MCS7780 needs that same format, it's just not
>>> documented as well.
>>> The packet wrapping looks like this:
>>> 0x55 0xaa 2-byte LE length, 0xC0*n .. escaped data .. 2-byte LE CRC
>>> and from what I can tell, the Stir4200 also resets to sane default
>>> values (9600 baud SIR).
>>> But you may have to do some USB control transfers to set the data
>>> direction. It *looks* like the MCS7780 is simpler and defaults to just
>>> "automatic data direction" (which presumably just means "send if there
>>> is TX data, receive otherwise").
>> Yes, but to me talking to the chip is the easy part. I'm more concerned
>> about implementing enough of the irda protocol stack to be able to talk
>> to all those embedded stacks.
> I discovered this a while ago:
> It seems to be based on some minimal IrDA stack for micro-controllers:
> This is probably a good starting point!
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