Programming PIC 16F628A with JDM programmer

[tushar]

hello,

I am facing some problem in programming the PIC 16F628A.

i have made a JDM programmer.

( circuit : http://www.geocities.com/leon_heller/pic.html )



and i am using the famous ic-prog (www.ic-prog.com)

When i upload the hex file in the PIC i am having a verifying error which says that
' Cant verify the bit 0000h '

and hence it does not program the pic !

Plz help i am in urgent help....


Thanks in advance..

regards

Tushar !

 

[Nigel Goodwin]

JDM's often don't work, so that's probably your problem.

 

[Blueteeth]

JDM's often don't work, so that's probably your problem.

Heh always helpful eh...

Theres loads of posts regarding the 'verify failed at address 0000h' with the JDM, try searching the forum. This error comes up if 'anything' is wrong...so its not exactly useful for debugging...all it means is IC-prog is attempting to send out data, but when it reads from the PIC, it doesn't get anything, as that is its only source of feedback to check if its connected or if it can communicate.

IC-prog has the ability to test the control lines so I would check the following:

1) make sure the VDD to the PIC is at least 4.5V. Should be 5v but anywhere between 4.5 and 5.5 sohuld be fine.
2) Check the voltage on the MCLR pin (pin 4 on the 628A), form memory I think the minimum voltage to get it into 'programming mode' is 12.7V, sohuld be arround 13V.

It could either be hardware, or software. XP/vista don't like programs big banging the serial port and you may need some sort of utility. I believe this is all covered on the IC-prog website.

Blueteeth

 

[tushar]

thanks for your reply...

i checked what u said ..

but i m getting 3.6V on pin 14 (vdd) and 0V at pin 4 (MCLR) which shud be 5V and 13V respectively as u said.

so what should i do now ?

should i connect an external battery for the JDM programmer ?

 

[Blueteeth]

When you checked the voltages did you check the boxes in the JDM hardware debugging dialogue? I could be wrong but I seem to remember IC-prog doesn't power the chip properly when it is not programming it.

Failing that, I believe your serial port can't provide enough power/voltage for the programmer. Laptops especially have this problem, as do new computers with serial ports, because the days when RS232 were +/- 12V are gone, most only output about +/- 7v ish (that goes for USB-RS232 adapters too).

Many programmers use an external power supply (15v) which can provide the 13v for MCLR, and then use a regulator for the 5v..in this case, the JDM style programmer simply switches these voltages, rather than actual;ly produce them from the power from the serial port, generally much more reliable.

I hate to say it, but I would cut your loses and buy a PICkit2 or a copy off ebay The chinese copies/cloines are very cheap, work with USB, and support many chips, worth it if you are planning on promgramming PIC's for a while.

Could you provide a schematic of the programmer you built? there are many variations of the JDM, some more reliable than others...

Blueteeth

 

[tushar]

okay ...

thanks for your reply..

The schematic for my JDM programmer is

http://www.geocities.com/leon_heller/pic.html



Plz check ..

Thank you ..

 

[Blueteeth]

Hi, I took a look at the schem on the site (the one in the zip file) and yep, its a stock JDM. As Nigel rightly pointed out these are woefully unreliable. If you can, try this simpler version:

**broken link removed**

I don't know why but when I started programming PIC's, the above version worked, when all others failed. Although, it does assume that your serial port can output +12.7V from the tx line to the MCLR pin, which as I said before, isn't usually the case these days.

This site has a good 'debugging' section for the JDM.
**broken link removed**

Then of course theres the software problem. IC-prog cannot always access the serial port under win2000/XP (god knows about vista) so there are some utilities that help it along. (xport?)

You must try to find out what is causing the problem, as the 'verify failed at blah blah blah' error isn't at all helpful. I usually start with hardware, as you have done, checking voltages etc..then software. Quite a good USB powered version is this:

**broken link removed**

You can replace the USB connector with a 5v supply, it generates (rather poorly I might add) the 13v via a voltage multiplier, regulated by a 13v zener and silicon diode, to make 13+0.6 = 13.6v. This is switched by an optocoupler (can be replaced by a transistor as I did).

That should help. Of course there is no point in building another JDM, but if you one really doesn't work after all that, consider buying one. They are a hell of a lot cheaper than you might think.

Blueteeth

 

[mvs sarma]

okay ...

thanks for your reply..

The schematic for my JDM programmer is

Simplest PIC programmer



Plz check ..

Thank you ..

You would have problems with that programmer you mensioned. Why not go for PICKIT2 as a one time measure. It might cost you in IN Rs3000/- and perhaps little more due to $ variations(i assume that you are in India). You can have it on Rupee payment from silicon components With this you can start concentrating of learning or practicing software, instead of killing your time around programmers.

 

[Emmar]

Please, is any body selling already programmed 16F628A

 

[Ian Rogers]

Please, is any body selling already programmed 16F628A

More specific please...

You want a programmer??? Or do you want a chip?