gnupic: DIY USB programmer ?
Subject:
Re: DIY USB programmer ?
From:
"Kevin L. Pauba" ####@####.####
Date:
5 Jan 2005 23:46:42 +0000
Message-Id: <41DC7CEE.4060603@cox.net>
Byron A Jeff wrote:
>On Wed, Jan 05, 2005 at 09:19:15AM -0500, Byron A Jeff wrote:
>
>[snip]
>
>
>You may not even need to do that. Consider if you tie the output of the
>555 back to the RX for the serial port, with no inversion. If the USB cable
>responds to a typical 0V-5V signal like ordinary PC serial ports, then you
>can transmit back the 555 timing back through the serial port. The low output
>is the standard idle state for the serial port, so when the 555 is triggered
>it'll send a start bit and some number of zeros before returning to the idle
>state. So testing should be as simple as sending 0xff to the serial port and
>then reading back the result. When the result gets to somewhere between 0xe0
>and 0xf8 then you know that the trigger is centered in the character cell.
>
>So it should just take a small piece of test software to get things going.
>I figure it can be a debug/setup feature of the actual programming software.
>
>
I've always been intrigued by the serial ascii programmer:
http://www.piclist.org/techref/com/picnpoke/www/http/projects/prog.html
I think it passes the "Radio Shack" test. I built one up and, as I
recall, it worked. I have some Java code around that drives it too.
What do you think?
