Thanks for your support (everyone!) :) "Right, I'm gonna build TLVP!".. got both IC's datasheets, hooked it all up, got to last connection, doh 74HCT125 only has 4 buffers :) Gonna make another order today/tomorrow to get that IC, probably some stripboard to put the *working* programmer on aand probably a toy for me (7-segment digit or similar). Hmm, maybe even a ZIF socket too! I must admit I believe most of my problems so far have come from the lack of a power supply capable of delivering 5V or ~13V "solidly". All I have are 4xRechargable AA (@4.8V) and a 12V "adjustable" power supply. People keep mentioning "bench supply" but of the 2/3 I've seen they were very expensive! (any UK people suggest where they got theirs?) All this for a coupla little chips :o -Kieren ----- Original Message ----- From: "Byron A Jeff" To: Sent: Sunday, August 04, 2002 1:06 AM Subject: Re: [PIC]: My latest woes! (programming) > 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 > -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu