On Sat, Aug 03, 2002 at 10:47:18PM +0100, Kieren Johnstone wrote: > OK, well this isn't working. > > If anyone wants to build me one (for a price, of course), e-mail me > individually and I can send you details.. > I only offer this because I feel there isn't a specific 16F877 programmer > out there and (evidently) I lack the knowledge to build one that works! ;) > > Of course, if anyone has ideas regarding my current setup that would still > be helpful!! > > Look forward to hearing from you ;) > -Kieren Kieren, I feel your frustration. I just went back over last month's archives and I realize that you've been working on a programmer for nrealy two weeks without success. That bites. In a post on the 24th you said that you'd take a crack at the TLVP. However I don't see a followup post where you said that you did and it failed. Here's some advise if you wish to take another crack: * Try building a low voltage programmer. It reduces the number of voltages to 1. Once you are successful in getting LVP to work you can work on adding the HVP component. And to answer a couple of questions that you asked a few threads ago: no you don't need 13V for LVP and it is impossible to clear the LVP bit from LVP mode. * You need to realize that the programming algorithms are different when you use voltages less that 4.5V. Any software that you use will expect the Vdd to be between 4.5 and 5.5V. Get a 5V regulated supply and use it. Since you are programming with a PC they abound. You can steal it from the keyboard, the joystick, the USB port, and if necessary from a disk connector. * Keep the parallel cable short, the shorter the better. No more than 2ft tops. * Verify the operation of every pin at the socket. Verify that you get both 0V and 5V at the respective pins (13V if you still decide to use HVP) What I've seen is that you've created too much variability. You're trusting that everything is going to work with marginal voltages. You've insisted on HVP programming even though your 16F877 doesn't require it. And instead of sticking to a single design, you've bounced from plan to plan to plan. The TLVP was designed for and works on a 16F877. It's designed for 5V operation and a short parallel cable. It has been verified with both FPP and my version of picprg2.3d. I'll even give you the variability of retargeting that 74HCT125 by suggesting that you use its buffers instead of the HC573 specified. Be sure to tie the OE pins low. If you reduce the number of variables and you test each individual pin on the programming socket, there is generally a quite high level of success. Take one more crack at it. If not then I'll solder up a THVP (adding the 13V Vpp circuit), test it, and mail it to you. BAJ > > ----- Original Message ----- > From: "Jim" > To: > Sent: Saturday, August 03, 2002 9:23 AM > Subject: Re: [PIC]: My latest woes! (programming) > > > > At 12:00 PM 8/3/02 +0100, you wrote: > > > > Hey guy > > > > >Hiyas, > > >I built Jim's programmer (uses 74HCT125 now)... anyway now I have the > > weirdest results yet (yay)! > > >Just as an example, I'll do some stuff riiiight now..: > > > > > >* Turned on +12V, +5V (actually more like 3.6V - 3xAA rechargable), but > > programming > > datasheet says this is fine) > > > > Hmmm I don't know about 12v did you build the 2 regulators into the > circuit? > > I'v seen it mentioned on the list before that 12v is pushing it. with the > lm317 > > you get 13v. I have been using my programmer to program my robot which has > > a large 12v gelcell and a 7805 regulator of it's own to power the 16f874 > but > > alot of times I get failed to program running it from that 5v. I have to > connect > > it to my bench 5v supply then it always works. So maybe you are have > trouble > > with your battery supply for 5v. > > > > > > >* Loaded FPP, checked setup (ok) > > >* Clicked read, ok > > >* Woo! Screenfulla' 3F8C's code, 00 00 etc. data > > >* Clicked load, loaded FLASHLED.HEX > > >* Clicked program, ok > > >* "Failed to program code!" instantly > > >* Clicked read, ok again, for kicks.. got 2C24 followed by 8 0000's, then > > all 3F8Cs. Near the end, 3FFF x4, 0000, then 3F16 09A5. Data is now all > > 80's! Config has also changed, from "####" to "2C24" > > >* Reset power supplies, clicked read, got 3FFF, load of 0000s, data all > 0000s. > > >* Ooie, transistor is hot.. I'll try turning it round *shrug*.. nope, now > > it all reads as --Blank-- and still fails to program.. turned it back, > reads > > 3FFF then 00s again. > > > > Ok I'm getting the feeling that your using an external 12v supply for mclr > > that may work > > for programming but if you are note the schematic you are connecting 12v > to > > the collector > > of the transistor through 100 ohms this may be to much current in the > > schematic 13v > > goes to mclr through a 2.2k then the transistor when turned on pulls it to > > ground > > through the 100ohm total 2.3k resistance. I used a 2n3904 suface mount > > transistor here > > and it's running cool. (god it's hard to concentrate with a 2 year old > > crying for barny) > > If you want to try programming with a 12v supply connect it to mclr > through > > a 2.2k > > > > If all else fails. Disable read by setting (read & in) in fpp setup to > nothing > > program the chip see if it flashes the led. > > > > Jim > > > > > > >* Doesn't work if I connect +12V connectly to MCLR either (with 100ohm > > resistor) > > > > > >I have... no idea.. if anyone is recognising anything click that lil > reply > > button :) Thanks > > > > > >-Kieren > > > > > >-- > > >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 > > > > -- > 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