5 transistor PIC programmer *Schematic added to step 9!

Make your own PIC programmer for your computer's parallel port. This is a variation of David Tait's classic design. It is very reliable and there is good programming software available for free. I like IC-Prog and PICpgm programmer. Best of all, it uses just two voltage regulator and 5 transistors!

*** I added a pic of the final result, and pics of my new mini-programmer with a clear top. Click the smaller images below!

** This is a new variation and it didn't work 100% correctly on the first attempt. I guess I got ahead of myself.. I have built several variations, and I thought I was on top of things. :) There are a couple of changes, but everything worked out in the end. I had to add an additional npn transistor and change a couple of resistor values. These changes are already reflected in this list, but are not updated in all the pics. See step 7 for pics of the software I use and how to set up the programmer.

You need:
A male DB25 socket
4x NPN transistors, such as the 2n3904
1x PNP transistor, such as the 2n3906
1x 7805 voltage regulator
1x LM317 voltage regulator (and appropriate resistors to make 12.5V)
1x 10k SIP resistor network
4x 10k resistors
1x 22k resistor* update for step 3
1x 5k resistor
1x 1k resistor* update for step 3
1x machined-pin chip socket
soldering iron, protoboard, wraping wire, wrapping tool, glue gun.

Step 1: Index card

If you have copper tape, lay a strip down as a ground plane. If not, put a row of staples into the paper along one edge and solder them together.

Then bend the legs of the SIP resistor network, and glue as shown.

Comments

[ali7509]

i have made the hardware as shown in the schematic in last step but i am unable to get the desired results ..
is the schematic in the last step is fine??

[klee27x]

Yeah, the schematic is verified by multiple people.

One thing about the selected resistor values is they're designed for low current draw. But this isn't ideal for ICSP with loaded lines. If you are trying to program a PIC out of circuit, recheck your wiring. If you're doing ICSP, you might want to decrease all the resistor values proportionally. Say 1/10 the values shown, just make sure your transistors can handle the current.

[matstermind]

is the schematic updated so it works?

[superbird]

The Project is great but the cat is the best!!

[sventeeuwen]

smurfy is so cute!!!

[klee27x]

... Hehe, yeah. This was an awesome picture. She fell asleep in my hand and I carried her around until she woke up. :) She had a litter and gained a few bazillion pounds since then, though. :)

[Sandisk1duo]

How about adding a socket?

[klee27x]

Well, adding a socket it ok for 1 type of chip. But this can program a lot of different chips. Many have different pinouts. So I prefer to just leave a port where you can plug in a 5 wire cable. Anyway, AFAIC the best way to program a DIP chip isn't with a socket. I've tried that. During debugging, you'll end up programming a chip dozens of times. Regular sockets are a PITA to put the chip in and out. ZIF sockets are slightly less of a pain, but they are sorta fragile; they don't last long in my hands, anyway. I prefer to wire up the programming connections to a breadboard, permanently. It's easier to use than a regular socket, and you can program in-circuit. Another nice thing to use is a chip clip. This it a plastic spring clip that goes over a DIP chip. It is quicker than any socket, and it can do ICSP even on chips that are soldered onto a PCB.

[Sandisk1duo]

so, would it be possible to program all types of PIC chips with this?

[klee27x]

Nope, not all. Theoretically it could program pretty much all chips that can operate at 5V. But in reality, it depends on what the software you are using supports. Back when I made this, I used PicPGM software. Some of the older, more "obsolete" chips weren't supported, such as the 10F and many of the 12F series chips. And 18F series chips were also not supported. But most all the recent 12F and 16F series flash chips were supported. This includes a good variety of 8 pin, 14 pin, 18 pin, 20, 28, and 40 pin chips. But if you used a different software, you might be able to program different chips. I think the other one I used was called WinPic, or something. Using that software, you could program a good bit of the 18F series. Nowadays I use Microchip's PicKit2 programmer, so I'm not really up on the latest free programming softwares.. :)

[klee27x]

Just as an FYI, even some of the nonsupported chips can be programmed, sometimes. What you do is set the software for a similar chip, with the same instruction word length and memory size, but then you have to read the datasheets to figure out how to set the configuration registers, manually, in hexadecimel. So it's a pain, but it can be done.

[Sandisk1duo]

is there any way to extract code from a microprocessor?

[jhong710]

i cant see where to put the pic here.. where do i put the chip to be programmed??

[klee27x]

From the header, you can plug in whatever you want. Sure, you can permanently wire a socket if you want. But I'd rather plug in a socket when I need it, because I rarely program a chip using a socket. And even if I did, there are many different chips you can program with this and many different pinouts. I've seen clever setups where a large ZIF socket is wired with multiple connections, so you can program several types of chips by placing them in different spots/orientations. But I'd rather not need to refer to a manual just to figure out how to use my own homemade programmer. :) When I get need to program a new chip, I look at its manual and hard-wire and/or breadboard a new programming adapter.

[tubbychick3n]

Haha. Your cat is so cute. I remember when my cat was that small.

[barthie]

if i just follow the schematic and not the instructions, do i still need the resistor network? i find the instructions a little confusing. also, has anyone tried this with a laptop? thanks

[klee27x]

Nope. Just follow the schematics. I also find the instructions very confusing. I no longer own a laptop with a parallel port, but I had one at one point BEFORE I made this particular version of the programmer. On other variations of the TAIT I had made, most did not work with the laptop's lower port voltage. I managed to make a version that worked with the laptop, though. What I did ended up doing was using a quad comparator to buffer all the signals so I could manually set the logic levels to whatever I wanted. In this case, you just need to reference the comparator inputs to a low voltage, like 1.5V, and you're all set. Now any voltage that is higher than 1.5V will switch the comparator, and there's your new laptop compatible logic level. So basically, you can replace all the 4 npn transistors with a quad comparator IC, if necessary and you know what you're doing. You don't even need the pnp to control the programming line, because the outputs of an LM339 are open-collector. They can be pulled up to whatever voltage you want. So you end up providing programming signals with pullups.. which means the output impedance is fairly high, but it should work ok as long as you're not doing ICSP with a lot of circuitry loading down those pins on your micro.

[barthie]

sorry, i'm just learning, so you lost me. i looked at the datasheet for the 339, but couldn't quite figure out how to replace the four npn transistoer with the chip. thanks for the reply though.

[klee27x]

Yeah, np. Maybe it would help to learn the theory behind it. Basically a comparator has 2 input pins and one output pin for each comparator. One of the input pins is usually set to a reference voltage from an external source. Then a signal is applied to the other input pin. When the voltage on the signal goes higher than the reference voltage, it makes the output pin change state. The way a comparator works it basically the same as an opamp, except it has a couple extra transistors on the output to make it go "all-or-nothing," which makes it work well for this app. For this particular app, you would make a voltage reference of 1.5V-2V anyway you want... with a resistor divider or using a voltage reference IC, or whatever. Then connect that reference to all four of the chips I(+) pins. Then anywhere you have a transistor, you connect the part that goes to it's base to one of the comparator IC's I(-) pins. The output of the comparator is what's called an "open-collector" output. So it's really just a transistor collector, itself. That goes where the transistor's collector would go. Pulled up to the positive rail and becomes the output signal. Well, I know that confused you even more. But I'm sure you'll figure it out if needed. Necessity is the mother of invention.. or of learning stuff. :)

[barthie]

maybe i understood better than i thought. i started drawing it out with the reference going to all four + pins of the lm339, but wasn't sure and tossed it. i'll give it another try tomorrow. thanks!!

[klee27x]

The whole point is to move the place where your programmer decides what's hi and what's low to a new, lower setpoint, so that it works with a laptop whose parallel port voltage might be 3.0-3.5V, rather than the 5V which is (loosely) standard for desktop machines. At 5V, the transistor circuit may require a signal to go up to 3.5Vish before it is considered a "hi." By setting the comparator reference to 1.5-2.0V, it now makes it work with practically any voltage.

[agis68]

Nice project i will try it. By the way cute cat

[klee27x]

it'll work for some pic18F's. To see, you have to look at the programming software you plan to use to see what it supports, then also you have to find out if it's supported on the TAIT programmer, which this basically is.

[little_dice]

This is really awesome what you've done here... I just wanted to know if the same rig can be used for a pic 18 series microcontroller...for sure... A speedy reply would be greatly appreciated...

[funlw65]

What if I using a separate PC source for 5V and 12V instead of LM317 and LM7805 (I have both regulators)?

[Puotta]

Has anyone verified that this works for a pic16F84a? I'm having trouble with mine, and after reading all of microchips documentation over icsp, it seems like the data I'm getting from my programmer is correct, but I'm still not able to burn them. I'm using icprog, and I swapped the 9volt for the 12volts from my computer.

[klee27x]

you inverted the data in/out and clock signal, right? And you left mclr signal non-inverted? And if using Win XP, you added the Driver that is necessary to run ICprog on WinXP? After downloading the driver, you also have to activate it. It is rather nonintuitive, so please check with the ICprog instructions for more info.

[Puotta]

yea I inverted everything. My setting look exactly like those in the picture. And I'm running this mess on a win98 computer. I'm gonna do some more tests today and see if I can't figure it out. Thanks for being helpful so far, I'm sure I'll have (hopefully a more specific one but still) a question or so for you later.

[Puotta]

muhahaha, I finally finished it. I burned a program onto the pic. It verify's and reads correctly. Unfortunately I haven't gotten a chance to check it in the test circuit, (I'm missing the correct capacitor). Either way, I'm pretty sure its working just fine. Oh the problem was just a messed up transistor. When I pushed it into the breadboard the leg bent, and I missed it. Eh well.

[klee27x]

Kewl! Glad it's working. I was starting to wonder if my schemmy contained an oversight. But didn't you mean to say "muahahaha," i.e. evil scientist laugh? "Muhahaha" doesn't sound right to me. :)

[Puotta]

hmm... I never realized I was typo-ing that... hmm... eh well now that I know I'm evil laughing properly I shall rule the world! muahahahahahaha! As far as I know your schematic is fine. Unless I changed something during my "poking" (proper engineering term). Well once I finish up a couple other projects I've got going on I might see if I made any mods... probably not though, I'm not that smart ;)

[klee27x]

I have verified it, personally. I have burned with a fresh 9V battery, even, but have found it takes 8.8V minimum to burn my 16F84a, using this exact programmer pictured. So 12V is definitely better.

[Puotta]

the one the schematic portrays? hmm. any probems you had, that I should look out for?

[James (pseudo-geek)]

cpl questions: no.1 can I please have your cat. no.2 I dont have that port on my pc I dont think - any way to use a USB port ot program it?

[TechnoMancer]

there should still be a serial port on your PC!!!!!!! what kind PC do you have?? i have one that was bought this year and it still has a serial port on it!!!!! it should be the one labeled with the 1010 it should be a kind of turquoise colour and have either 9 or 25 pins Hope this helps

[James (pseudo-geek)]

I'm sorry, it does have one. is the serial port the printer port or the smaller ones?

[TechnoMancer]

The printer port is a parallel port the serial ports are male 9 or 25 pin ports!!! the printer port is a female connection!! but this programmer needs a parallel port so the one you want is the printer port!! kk TechnoMancer

[James (pseudo-geek)]

thanks

[TechnoMancer]

And if you want to build a PIC programmer then build the one thats called a Business card pic programmer here: http://www.instructables.com/id/EWF5MO717GEWT14B3B/?relatedLink
that one is completely powered by the serial port and so is more compact!!!

[burzvingion]

While building a PIC programmer is all very well and dandy, it's really more work than its worth in my opinion, unless you only plan on using last century's 16F84s all the time. if you're really serious about getting into microcontrollers, the PICkit 2 is what you want. It can handle most any 10, 12, 16, or 18F device microchip has come out with, all the way up to a good number of 24F and dsPICs. It uses a USB interface, so it's very fast, and it comes with a software interface thats easier to use than a microwave. And they include a pretty nice C compiler to boot. To top it all off, you can buy it for $50. If you feel like making your own breakout board, and don't need a C compiler, you can get just the ICSP programmer for $35.