On Sat, Jun 12, 2004 at 01:03:02PM -0300, Octavio Nogueira wrote:
> Let's see Byron:
>
> The main problem is the flash write.

It flat doesn't work? What happens?

>
> Using the bootloader from
> http://www.microchipc.com/PIC16bootload/16F87xA/
> I can send and receive data, I did the software UART and it's working great.
>
> The same with Tiny bootloader.

OK. Cool.

>
> When it's time to write the flash the trouble starts.

OK. What do you do, and what happens when you do that? Let me go take a quick
look at Tiny. OK Done. I observed three things:

1) That Tiny's firmware doesn't deal with the issue of block writes. Nor does
it need to IMHO. The PC software can deal with that issue trivially by
ensuring that a block starts on a 4 word boundary and whose length is the
multiple of a 4 word boundary (8 bytes).

> Another proble is the flash erasure. I hace to erase blocks of 32 or 64 I
> can't remember.

2) There's no erase sequence. I noted that the 18F loader did do an erase.
It's not difficult to do and only requires one extra bit set (FREE) over an
ordinary write. It should be simple enough. I am unclear if it is required
though.

3) Tiny needs a dump memory command that reads the program memory and fires
back the contents to the PC. It would require another command to do.

> > My friend, when money is exchanging hands, location doesn't matter.

> Yes, I know but I'm sure a user in USA can effort much more money than a
> user in Brazil.

Don't be so sure. We all have different circumstances.

My assessment is that Tiny should work on the 16F819 as long as the packet
sizes meet the requirements outlined above. Personally I'd try to dump a
hex file into it, then put it in a programmer and read back the memory
contents.

Also I'd probably continue to battle with Tiny if for no other reason than
the fact that it's tiny, so there are a very limited number of things that
can go wrong with it. I figure I could take Woj's linwload and turn it into
a lintinyload in less than an hour. Note to self! ;-)

>
> > BTW just curious: why is getting a bootloader for the 819 so critical?
> This is a temperature logger project I'm finishing and the dead line has passed already. I need to
> be able to upgrade the code after I ship the units.

OK. Understood. I really hate those deadline things. ;-)

>
> >One last thing: you are using an external crystal or resonator right?
> No, I'm using internal osc but as I said the communication is working great.

That's probably not a good idea. If the temp of the unit is even 5 degrees F
different than your test bench, then it'll stop working. Just a warning
up front.

BAJ

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.