Hi Pete,

Short term yes, atmega328 long term doesn't matter so much i.e. samd21,
stm32, teensy or whatever.

The idea is to be able to provide a secondary mode to WSPR for a Pico
Balloon tracker. WSPR works well as primary mode but the desire is to have
a secondary mode as well - kind of a belt and suspenders idea.  The current
tracker hardware is nothing more than a GPS module, atmega328 and si5351a
synthesizer. Very simple and very light weight but the atmega328 is the
limiting factor. I am not even sure I can squeeze everything required for
WSPR and FT8 into the 32k program space plus there is only 2k of ram.

I tried long long and uint64_t, and ULL. They all compile but in the end
are still only 4 bytes. There are some online posts to the contrary but I
couldn't get more than 4 bytes.

I have free text working using the FTEcode arduino library by NT7S and
sending something like CQ VE5VA FN02 does get copied correctly by WSJT-X
and uploaded to pskreporter BUT CQ VE3GHM FN25 gets truncated and drops the
5. So, unless we have access to a call sign with 5 characters we would need
to be able to properly encode a standard message.

This has been an interesting exercise and may in the short term not go
anywhere but at least I will have some background when we decide to move on
with a more capable processor.

cheers, Graham ve3gtc


On Thu, Jan 2, 2020 at 8:21 PM Pete <[email protected]> wrote:

> Graham,
> > The atmega328 is an 8 bit controller and Arduino is limited to 32 bits
> > (i.e. 4 byte) and I have so far been unable to come up with some
> > workaround that lets me do this 64 bit stuff on Arduino
>
> There is a uint64_t (and int64_t) datatype which allows you to work with
> a 64-bit word on the atmega328, even though manipulating them will
> require the compiler to add support routines (e.g. using the ^ operator
> adds about 220 bytes of code). 64-bit constants just require the LL or
> ULL suffix - e.g. 0xffffffff12345678ULL. But do you have to use the 328?
>
> I have ported the FT4 encoder to a Teensy4 with free text and telemetry
> messages but I haven't bothered (yet) to add the encoding of callsigns
> and hashes.
>
> 73 de Pete VE5VA
>
>
>
>
>
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