Very Simple ICSP Programmer

[rabidgoalie]

Like Ramonetnet, I tried to use the Stolz LVP cable design with no success, and then I rooted around the Internet to find a way to get a PIC programmed quick and easy. Luckily, I found this thread. I am going to construct the Stolz ICD2 clone, and I didn't have any type of programmer before I found this thread and without a programmed PIC16F876A I wouldn't be able to construct the ICD2 clone (obviously ). I read through this thread about five times to make sure that I did not confuse any information, and then I breadboarded this simple programmer (using the setup below, exactly how Squibcakes illustrated in the first post) and everything works great!

I made sure to test the levels on my serial port to make sure that they were within the range that seemed to be working for everyone (~11.25V), and they checked out fine. I am using Win98 as the OS because I have an old (but still good) Packard Bell 880, and I am very pleased to say that IC-Prog seems to program much faster under Win98 than under XP. For some reason, I was getting an error from WinPic800 (similar to the one that charudatt was getting from IC-Prog), but I switched to IC-Prog and used the recommended settings and it worked great. Hmm, don't really know what is going on with that but IC-Prog works for me so I will worry about it at a latter date (i.e. I will never think about it again after tonight ).

I was able to program the PIC16F876A, verify the programming, and then just to be thorough I closed down IC-Prog and restarted it and read the data back and it all worked flawlessly. Thanks Squibcakes!


TXD (3) ------[4.7k]-------VPP (PIN 1)

GND (5) --------------------VSS (PIN 8 or 19)

DTR (4) -------[4.7k]------DATA (PIN 28)

CTS (8) ------------------DATA (PIN 28)

RTS (7) -------[4.7k]------CLK (PIN 27)

+ (5V power supply) -------VDD (PIN 20)

- (5V power supply) -------VSS (PIN 8 or 19)

P.S. sandeep, when I programmed this PIC16F876A I left PGM unconnected (floating), and I had no problems at all programming, verifying, and reading back the programming inside the PIC. Others could probably help more on the PGM pin than I could (I am still a newbie at this). Hope this helps someone.

[marksk]

i've seen it mentioned not to use a laptop because there isn't enough voltage from the serial port. would i be ok if if i used a separate power supply to provide +5V to the pic?

[Squibcakes]

Hi Mark,

This circuit requires an external 5v regardless. In saying that, I haven't had much luck using laptops when programming pics with this circuit. (after all this is a very simple cheap programmer!)

Laptops don't put out high enough voltages on the serial lines.

Attached is copy of circuit board you can use to make this programmer. Have fun!

Cheers

[marksk]

tried my laptop over the weekend to no avail. i used an external supply for the +5v, but each time i tried i got an "verification failed at 0000h". i also tried applying +12v to MCLR to get it into programming mode, but that didn't work. i prefer to use the laptop for several reasons:

1. it fits nicely in my work area
2. it's 10 years old and isn't used, so if it blows it's no big loss
3. i've got problems if i use my desktop pc and it blows

i have an old 486 pc in my garage, but i don't have a spare monitor or keyboard for it.

can someone point me to a schematic that would allow me to use the laptop? (preferably with easy to find parts) if i use my desktop for the LVP programming, what are my changes of killing the pc?

thanks!

[nomad]

you can't just apply +5, and +12 for power and Vpp and have it work. there's timing issues, when it applies the voltage, which is first applied, to even get into programming mode. these voltages need to be controlled by the programmer. some newer JDM's use external supplies, but it still controls when they're applied to the pic.

as everyone has been saying, break down and buy the pickit2, or other.

by the time you build the cheapo serial one, buy a cable, waste hours upon hours trying to get it to work, you'll have spent way more than if you bought
the pickit (or other) in the first place..

here's the kicker, even after you get an enhanced jdm, get it to work, get/make external supplies for +5/+13, make a housing for it with switches etc, and tweak the software to run off your laptop with a usb converter...............

You'll end up buying a different programmer for the other features.!
(say um, pickit2? for serial i/o, logic injection/analyzer, etc..)

oh, and if code protect is on, it will always fail verification.. even if it programmed fine, it will be unable to read the code to do the verification. :/