Problems with JDM2

[PeterDove]

Hi All,

I built a JDM2 programmer from the following link

**broken link removed**

It work fine on my 40 pin PIC16F871, it works fine on my 18pin PIC16F628. I can even run wires from the 40pin DIL socket to a breadboard and program the PIC16F628 and PIC16F871 using the appropriate pins.

What I can cant seem to do is program the PIC18F2455 using the 28pin socket or even using the ICSP type method mentioned above. WinPIC800 which supports the chip does not recognise the device and it IS supposed to. It does recognise the other two mentioned.

Does anyone know why the PIC wouldnt be recognised or allow me to program it? I got a batch of samples from Microchip - could they be duff?

Any help appreciated

Peter

 

[eblc1388]

I don't think you have got duff chips.

The 18F2455 and 18F4455 are difficult chips to be programmed using JDM type programmer. On my first PIC programmer(JDM), it failed to even read the device ID, while the programmer worked for all other types of PIC.

Back then I was using WinPic and there is an option "Slow mode" to check for possible timing problem. I selected "Slow mode" and then I can read the Device ID and flash memory without problem.

 

[evandude]

Are you utilizing the PGM pin, or just PGD/PGC/VPP/VDD/GND? I seem to remember that the first time I programmed an 18F4550 with my JDM it didn't work until I hooked up the PGM pin, despite the fact that none of the other PICs I had used had ever required it. I am using a prebuilt JDM from https://www.sparkfun.com/commerce/product_info.php?products_id=9
I'm not sure if it's the original JDM or the JDM2 design.

I could be confusing it with a different chip though, it's been a while.

 

[mvs sarma]

Hi All,

I built a JDM2 programmer from the following link

**broken link removed**

It work fine on my 40 pin PIC16F871, it works fine on my 18pin PIC16F628. I can even run wires from the 40pin DIL socket to a breadboard and program the PIC16F628 and PIC16F871 using the appropriate pins.

What I can cant seem to do is program the PIC18F2455 using the 28pin socket or even using the ICSP type method mentioned above. WinPIC800 which supports the chip does not recognise the device and it IS supposed to. It does recognise the other two mentioned.

Does anyone know why the PIC wouldnt be recognised or allow me to program it? I got a batch of samples from Microchip - could they be duff?

Any help appreciated

Peter

Hi Peter,

if you go thro the winpic800 ver3.60 is latest,

one you select the device as pi18f and actual device as 18f2455,

if you prss the device tab and seek info about the device, you get a page to read abt f2455
as you go down, at one place i saw these lines.


"• Single-Supply 5V In-Circuit Serial
Programming™ (ICSP™) via two pins"

thus it is clear that there is a change in programming method and perhaps Vpp is also 5 V in this case.

and only 2 pins are used. ( obviously as Mclr may now be at Vcc) Just try to read little more from Microchip 2455 ICSP prgramming methods, i believe thaT YOU CAN GET THE ANSWER.

MAY BE TOO EARLY TO DECLARE DEVICE AS DEAD unless perhaps we kill then without knowledge.

 

[PeterDove]

I don't think you have got duff chips.

The 18F2455 and 18F4455 are difficult chips to be programmed using JDM type programmer. On my first PIC programmer(JDM), it failed to even read the device ID, while the programmer worked for all other types of PIC.

Back then I was using WinPic and there is an option "Slow mode" to check for possible timing problem. I selected "Slow mode" and then I can read the Device ID and flash memory without problem.

Hi, Thanks for the heads up on the fact that these chips are more difficult. I actually made a quick parallel programmer and this programs the chips perfect. Just in case it helps I have posted the link below to the site which sells them. They also give out the circuit diagram which I used to make my own. It is one of the simples programmers I have seen.

**broken link removed**

Peter

 

[eblc1388]

Hi Peter,

Just like to let you know the 74LS05 open-collector max. output voltage is only 5.5V and thus is not in specification working to switch 13V. But it will mostly works anyway.

This is a common mistake many similar programmer designers made. The correct choice is 7406 or 7407 but they are hard to get.

Edited: The 74LS05 is used in the above mentioned programmer.