JDM Programmer for 16F628A

[magester1]

Now, before all of you start telling me to search around for this, I tell you that I already have, I've read almost everything that has to do with that PIC in this site.
My doubts aren't exactly about how to make it work. I've read about pulling PGM to Vpp.
The issue I want to address is reprogramming it. Since it is impossible because of the lack of Vdd control the JDM has. I've found various solutions for this, however, most of them where tested and recomended for the 12F629/675. Which brings me to my question: will this solutions work as well for my PIC 16F628A ?

**broken link removed** <- This is the one I'm concidering since it looks like a simple thing to do. By the way, what can I replace the 2N7000 for? Here I can only obtain IRFs...

**broken link removed**

Thanks for your help.
And please don't recomend me building or buying another Programmer since it is not an option for me, at least not at the moment.

 

[mvs sarma]

You have almost shut the doors for any dialog by many restrictions. How ever, you can use any N MOSFET like IRF540
I use DL4YHF version of JDM, in addition to few others and a Pickit2 that purchased from Microchip.. DL4YHF PIC programmer works with external power supply. It has built in Vpp before Vdd. Really helpful. You may perhaps study that in order to get an Idea as to how to manage yours . The link and specific schematic are here
http://freenet-homepage.de/dl4yhf/winpic/index.htm
look for A programmer for FLASH- and EPROM-based PICs

All the best

 

[dougy83]

Pulling PGM to Vpp?? Try pulling it to ground. I've programmed '628s by connecting PGM to GND using a JDM programmer (HV prog). I think programming failed before I did this with the '628, but it didn't matter for the '648.

According to this errata, https://www.electro-tech-online.com/custompdfs/2010/01/16f628_errata.pdf, during programming PGM must not be allowed to toggle during programming.

So you shouldn't need to get any extra parts

 

[magester1]

You have almost shut the doors for any dialog by many restrictions. How ever, you can use any N MOSFET like IRF540
I use DL4YHF version of JDM, in addition to few others and a Pickit2 that purchased from Microchip.. DL4YHF PIC programmer works with external power supply. It has built in Vpp before Vdd. Really helpful. You may perhaps study that in order to get an Idea as to how to manage yours . The link and specific schematic are here
PIC Programmer for Windows - Help Index
look for A programmer for FLASH- and EPROM-based PICs

All the best

I guess I didn't look that much. I hadn't seen THAT programmer.
It does look like a good option and already having a built in Vpp before Vdd will make my life easier.
By the way, seeing it uses WinPic, it also works with IC-Prog, doesn't it?

 

[mvs sarma]

You can use winpic800 driver from WinPic800 - Inicio a free download. I do use the same.

 

[magester1]

By the way, I was wondering about a difference between your Programmer and the classic JDM.
Why is is that the latter one has every single pin of the PIC coneected while the DL4YHF has only pins 4, 5, 12, 13 and 14 connected?

 

[mvs sarma]

By the way, I was wondering about a difference between your Programmer and the classic JDM.
Why is is that the latter one has every single pin of the PIC connected while the DL4YHF has only pins 4, 5, 12, 13 and 14 connected?

Nice question magester1
if you see carefully the one you have posted has a red rectangle drawn indicating that it could accommodate an eeprom directly. simply speaking the 18pin socket can accommodate more types of pins so the wiring is done appropriately with no offense to any of the unused pins of 18 pin chip when to be used.
In general, we just need 5 pins to connect to the PIC. they are Vpp. Vss, Gnd, Pdata, Pclki generally use a bread board where the target chip is located, connect the concerned wires to the apprpriate pins, enable the programmer and do the programming and call it a day
i never use any 18 pin, 4 pin , or 14, 40 or 20 pin sockets or for that purpose, any ZIF socket

 

[magester1]

You mean in circuit programming, right?
Well, it seems easier, and I wouldn't have the risk of breaking on the pins. However I'm starting with microcontrollers and don't even have a circuit designed yet, so I don't know if that's an option for me...

 

[mvs sarma]

the programmer is used for programming the needed software into the micro-controller, to enable it do perform the tasks you want it. For a new comer, there might be some difficulty in placing and removing the chip from the socket or bread board for programing. In standard boards they provide these 5 pins as a set for external access. Some precautions are taken that your designed circuit wont interfere with the programming needs. In such cases. We can simply connect it to those pins called ICSP (In Circuit Serial Programing) connector.
As you slowly progress you would surely appreciate these things.

 

[magester1]

Sorry I didn't write before.
One last thing, looking at the DL4YHF circuit I see it recommends a 12.7V power supply if you have any. And looking around I read everyone talks about using 13V for programming.
I can use a regulated 12V power supply. I don't think it would make a difference, however, I'd rather ask before actually doing it. Don't want to risk not having enough voltage to enter programming mode by a few hundred milliVolts.
So, would it work without any problems if I use it?

Thanks for all you help.

 

[mvs sarma]

Sorry I didn't write before.
One last thing, looking at the DL4YHF circuit I see it recommends a 12.7V power supply if you have any. And looking around I read everyone talks about using 13V for programming.
I can use a regulated 12V power supply. I don't think it would make a difference, however, I'd rather ask before actually doing it. Don't want to risk not having enough voltage to enter programming mode by a few hundred milliVolts.
So, would it work without any problems if I use it?

Thanks for all you help.

the paper says that if you have a 12.x regulated voltage you could avoid the 7812 and the diode used in common lead.
you may try the rest of circuit as most programmers work with 12V asVpp. balance circuitry you may assemble and try it. it works. managing a 12.7V from any home brew 12V regulated supply may not be a problem as by isolating the common lead and adding a diode ( same element as used by programmer) in forward direction between common and Ground raises the out put by around 0.7V

 

[magester1]

Sorry to bother you again, but living in a damn small city makes everything more complicated.
I cannot get any kind of Schottky diodes here. So I wanted to know if there was something else I could use. Since it says that the 1N4148 (which I have lots of) wouldn't work.
Or maybe some other diode (NOT Schottky, of course) that I could replace them for.

If not is there anything you would suggest?

 

[mvs sarma]

Sorry to bother you again, but living in a damn small city makes everything more complicated.
I cannot get any kind of Schottky diodes here. So I wanted to know if there was something else I could use. Since it says that the 1N4148 (which I have lots of) wouldn't work.
Or maybe some other diode (NOT Schottky, of course) that I could replace them for.

If not is there anything you would suggest?

forget and replace all of them by 1N4148 , we used the them only

 

[DevilMKD]

Try this, for me work good