How to program PIC24J64GA002 by JDM programmer?

[arupbsk]

PIC24J64GA002 is a 3.3volt chip and I heard that the JDM based designs that use PCs COM port, can work only with 5volt PICs.
Can I use resistor based voltage divider in programming pins to use that? Or, what I should do?
I'm not in mood of buying or making IDC or PicKit.
But if those are the only way, then give me a link of diy project of making the kit.
(I know there are lots of threads here about those, but give me a link of that device customized to use with 3.3Volt devices. )

 

[wp100]

Hi,

If you are not in the mood for making a Pickit clone why would you want to mess around with a jdm ?

If you can get a pic18f2550 programmed up you can easily build a basic Pickit2 clone for just a few dollars.

It programs 5v chips fine, for 3v3 chips like the Pic24s then simply run the whole Pk2 circuit via a 3v3 regulator , it still works fine at the lower voltage - I have programmed a Pic24 this way many times.

 

[arupbsk]

Hi,

If you are not in the mood for making a Pickit clone why would you want to mess around with a jdm ?

If you can get a pic18f2550 programmed up you can easily build a basic Pickit2 clone for just a few dollars.

It programs 5v chips fine, for 3v3 chips like the Pic24s then simply run the whole Pk2 circuit via a 3v3 regulator , it still works fine at the lower voltage - I have programmed a Pic24 this way many times.

If that's the way, then I have searched google for diy pickit2 clone and found this
Google Translate

This design doesn't have a level translator on that programmer. Can I use a LM1117-3.3 regulator and give supply of 3.3volts to the 18f2550 and then use it to program the PIC24?

I mean will the 18f2550 initialize completely in the 3.3volts supply ?

If you have any other design in mind, say the one you built, please expose the link here.

 

[wp100]

Hi,

That looks a well detailed project though cannot see the full schematic ..? though as you say it seems to be without the output voltage control.

A Lm1117 should be fine, just connect it the the +5v usb input voltage and its output to the whole Pk2 circuit, just use a small switch so you can select 5v or 3v3.

My Pk2 always works fine at 3v3 .

 

[arupbsk]

That looks a well detailed project though cannot see the full schematic ..? .

As you haven't found the link to the schematics in the page, I've attached that. Please check.
It's a bit surprising that this clone doesn't uses any eeprom array.

 

[bigdogguru]

Actually, I've had good success buying ICD2s and ICD3s on eBay for the past several months.

The last ICD2 I purchased back in the beginning of July was only $40 shipping included.

Almost too inexpensive to build at that price?

Just a thought.

BigDog

 

[arupbsk]

Actually, I've had good success buying ICD2s and ICD3s on eBay for the past several months.

The last ICD2 I purchased back in the beginning of July was only $40 shipping included.

Almost too inexpensive to build at that price?

Just a thought.

BigDog

Hi bigdog,
I am not into serious PICing. I just need to program the PIC24 once.
I'll make the discussed pk2clone in around 10$ and yes, I'll program the pic18f of the pk2 by jdm, then i'll program the pic24 by the pk2clone and then I'll disassemble the pk2clone and use the pic18f elsewhere.

 

[bigdogguru]

I understand. It was just a thought.

BigDog

 

[wp100]

Hi,

Yes that looks like the minimal Pk2 clone, it does not need the eeprom for standard programming.

The choke shown is 680uh though it still works fine down to 470uh.

D2 is specified as 1n4148 which gives a drop of 0.7 v which can be too low for some chips if the usb voltage is low to start with.
Normally it is a Schottky type so the drop is only 0.2v though for your one off direct programming of the chip you could leave it out.

Test if first a 5v to ensure it works ok, then add your 3v3 regulator.

---------- Post added at 22:05 ---------- Previous post was at 22:03 ----------

Hi,

Sorry, error on that last post, the diode referred to should be D1 not the D2 I mentioned.

 

[arupbsk]

Hi,
D1 is specified as 1n4148 which gives a drop of 0.7 v which can be too low for some chips if the usb voltage is low to start with.
Normally it is a Schottky type so the drop is only 0.2v though for your one off direct programming of the chip you could leave it out.

Test if first a 5v to ensure it works ok, then add your 3v3 regulator..

Is there any problem if I short the diode to supply real 3.3volt from the ldo regulator to the target PIC?
Also, can I supply the real USB 5V to the PIC18 and the ISCP header, I supply 3.3Volt to the target PIC24. There are 33E resistors in all programming pins, I just connect each programming pin to GND via a 3.3V zener diode so that the voltage level to the target PIC is justified.

PS: The use of the 3.3V supply to whole circuit is the simplest idea, but I thought of using this complex way so that the voltage level in every programming pin of target PIC is stable at 0-3.3V, so that I don't need to worry about the 4148 diode voltage drop, etc

 

[wp100]

Hi,

Why complicate something you want to keep simple ..?

If you must, then rather than add zeners etc just add the extra circuitry to the clone to add target voltage control.
All the circuitry is shown in the Pickit2 users manual.

D1 is there to stop any voltage present in a separately powered target circuit feeding back onto the +5v usb power line.