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From: | Szymon Ulatowski |
Subject: | Re: [avrdude-dev] PDI capable bitbang programmers? |
Date: | Sun, 05 May 2013 13:14:15 +0200 |
User-agent: | Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.23) Gecko/20110922 Thunderbird/3.1.15 |
On 05/05/2013 10:52 AM, "Ing. Daniel Rozsnyó" wrote:
I have started to compare TPI and PDI - seems very similar. The TPI has a dedicated reset wire, so PDI looks like a subset of TPI, with no modification required.
last year i considered implementing PDI on FTDI but i gave up after learning that FT232R is unable to produce long and stable sequences of clock signal because of its hardware bug - the chip spits out all received data very quickly instead of buffering the packets and clocking output pins according to the configured frequency - see "TN_120 FT232R Errata Technical Note" - "3.1.2 BitBang Mode variable Pulse Width" http://www.ftdichip.com/Support/Documents/TechnicalNotes/TN_120_FT232R%20Errata%20Technical%20Note.pdf and this is very unfortunate because PDI requires at least 10kHz clock - ideally we would configure the output clock to 20kHz (or more) and send an USB packets of 01010101 - but they screwed it and the result is a quick burst of clock followed by a pause (and pausing the clock disconnects PDI) :-P so i gave up and decided to implement PDI in USBASP that is so ubiquitous and cheap
http://szulat.blogspot.com/2012/08/atxmega-programmer-for-050.htmlbut of course the FTDI implementation would be so much better (if it is really possible) and i wish luck to anyone trying to accomplish this goal!
sz.
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