What you need to be aware of is that READ is an OUTPUT. I realize that it's a bit weird, but that's the way of things. IN is the only pin you should be worrying about at the moment. Try leaving READ undefined. Check that pin 7 of the D-sub connector is in fact at a high logic level, since it has to be for IN to work. Failing all this, there is a discussion group devoted entirely to the FPP software that probably has what you need in its archives. Lots of info about little quirks and gotchas of the Tait-style programmers. I got caught once by not knowing that if programming failed consistently in the same place on a chip, with the 7406/PNP configuration, the solution was to place 2 10nF capacitors from the CLK and OUT lines to GND. You can't get that kind of thing from documentation. A simple Google with "fpp tait PIC message board" will probably turn up that board with little work. Hope that helps. --Brendan ----- Original Message ----- From: "Peter Jeffe" To: Sent: Thursday, July 04, 2002 3:32 PM Subject: [PIC]: LPT pin assignments for TOPIC2 programmer > Sorry if this is a dumb newbie question, but I just can't find the answer or > figure it out. > > I've built David Tait's TOPIC2 programmer to use with a 16F627-20 and I'm > trying to figure out the pin assignments between the LPT port and the PIC. > I think I have the following right, but I could be wrong: > > Function LPT pin PIC pin > > -------- ------- ------- > > OUT 14 RB7 (13) > > CLK 1 RB6 (12) > > MCLR 16 /MCLR (4) > > PGM 17 RB4/PGM (10) > > > > And I have no idea about the READ and IN pins. I've tried everything I can > think of involving LPT pins 11 and 2, and it's probably blindingly obvious > to the initiated, but my lack of understanding is definitely hindering me > here. > > If I leave READ and IN undefined in FPP then it succeeds in programming, but > I haven't been able to get anything running. If I can get the read working > then that would be the logical next step so that I can at least know that > it's being programmed correctly. > > I'm really trying to come up to speed on this, but I'm just not finding the > kind of intro material that I need to get past this stage. I have read the > programming spec from Microchip and all the FAQ pages and links I can find, > and I'm just not getting any closer. I realize now that if I had gone with > another programmer design it would have more support, but I don't want to > have to throw away the TOPIC2 and start all over again (and it fits so > nicely in a DB25 shell :-). So thank you in advance for any help. > > Peter Jeffe > > -- > http://www.piclist.com#nomail Going offline? Don't AutoReply us! > email listserv@mitvma.mit.edu with SET PICList DIGEST in the body > > -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body