gnupic: Programmer
Subject:
Re: Programmer
From:
"Andy N1YEW" ####@####.####
Date:
1 Dec 2000 12:52:37 -0000
Message-Id: <008d01c05b95$f81ed9c0$474b3ea6@andypc>
i'll read it and then let ya know what i think :)
ok this is what i think...
i'll use a 16f84 as a serial-parralel converter. then i will make it
bi-di(enable tx thru a pin if i need the functionality :)
hows that sound???
alright?
Andy N1YEW
----- Original Message -----
From: "Kevin L. Pauba" ####@####.####
To: "Andy N1YEW" ####@####.####
Sent: Thursday, November 30, 2000 11:50 PM
Subject: Re: Programmer
> Andy N1YEW wrote:
>
> >
> > >
> > > >
> > > >
> > > > I may use a design like Tony Nixon's ASCII programmer.
> > >
> > > I'll be writing a driver for Tony's ASCII programmer for jpp877 but be
> > > forwarned: programming a '877 with the ASCII programmer (at 1200 baud)
> > will be
> > > really slow. I'm mainly doing it because I've alread built the
hardware
> > so I can
> > > use it to test my first driver for a serial port programmer.
> > >
> >
> > Is there no reason why one cannot just switch the baud rate to 9600? or
> > slower? or faster?
> >
>
> Yeah, I think it is designed to work at 1200 baud and will probably fail
at
> 9600. You'll notice that it uses a couple of RC circuits that depend
heavily
> on the timing provided by the incoming serial stream. At a higher baud
rate,
> I would suspect the voltage levels at UA1/pin 2 wouldn't be up to a logic
> level to trip gate.
>
> The ASCII programmer sends 9 bits serially from the PC for every one bit
sent
> to the PIC. So, to program one instruction on the PIC we'd have to send
34
> characters (6 for the LOAD_DATA command, 16 for the instruction, 6 for
the
> BEGIN_PROGRAMMING command, and 6 for the INCREMENT_ADDRESS command). And
this
> doesn't include the 28 characters needed to verify the programmed
> instruction. Now, at 1200 bits per second (assuming 1 bit per baud), 9
bits
> per character (1 start, 7 data, 1 stop), and 34 characters, this works out
to:
>
> (9)(34)
> ----- = 0.255 seconds per instruction
> 1200
>
> I have a simple walking LED program that loads on the '877 and is 48
> instructions so this would work out to about 12 seconds. The other
programmer
> I am using reads, programs and verifies in 1.2 seconds.
>
> David Tait's archive has a ASCII programmer that is more complicated but
it
> might run at a higher baud rate and is able to sends 9 bits serially from
the
> PC for every three bits sent to the PIC. So, it would program three times
> faster than Tony Nixon's ASCII programmer at the same baud rate. Let see
if
> I can find the link ... shuffle, shuffle ... here it is:
> http://www.gnupic.org/burn/mipi.zip. Read it completely; it starts out
> sounding like just another parallel port programmer but then gets into the
> nitty gritty of an "RS232 Hosted Parallel Port" (essentially a
> serial-to-parallel converter). I think it's pretty cool.
>
> Hope this helps!
>
>
> PS: I used lots of C++ in my graduate studies so I know how you feel.
I've
> come to really like Java, though.
>
>
>
