Problems with 18f2455 and JDM

[n8thegr8]

Hi! I'm a noob here (and to microcontrollers in general) but I couldn't find anything relevant to my problem anywhere so i thought i'd post. I've built this obdII USB interface based off of the pic18f2455: **broken link removed**

I'm trying to burn the hex file for it using the diy JDM here:
**broken link removed**
(**broken link removed**)

My problem is, I've built it all, triple checked the connections, and WinPic still errors on flashing. The only thing I can see possibly wrong is that the Vpp is around 11.5 instead of the 12.5 for programming. The interface initializes perfectly in WinPic, Returns 1 for DataIn, but it fails in verifying by reading FF's in some places.

On that guy's site, he says something about WinPic not handling the config registers properly for the 18f2455, and that injecting two lines into the hex fixed it for him, but it doesn't for me.

Should I try to get the voltage up? or is 11.5 close enough? I'm at wits end here with all this. Thanks!

 

[n8thegr8]

well, I fired up my comp under ubuntu and ran piklab against it and it programmed! up to a certain point....it keeps failing at random addresses, and when I read it back, the code is fine up until that address when it all goes to hell. The fact that it's not failing at a specific address or even in a specific range gives me hope that the chip is still alive. I've tried pulling pgm to ground, adding an external power source to vdd, and it doesn't make a difference. I'm beginning to loathe jdm, but I'd rather not spend more money if I can keep from it...damn it all...

 

[Nigel Goodwin]

Well JDM is the most troublesome PIC programmer you can build, I suspect it was designed to prove a point (smallest number of parts possible) rather than as a practical programmer.

 

[n8thegr8]

Well JDM is the most troublesome PIC programmer you can build

haha, you got that right. well, I just tried using a different external power source (the first time was a usb connection, and I read about the grounding issues, so I used an ac adapter) and winpic800 picked it up, wrote, and verified the chip successfully. However, when I tried to verify it after programming, it failed reading all 0's, so I'm hoping it wrote and maybe there's some sort of read-lock on it or something, I'll hook up the circuit later today to test.

 

[futz]

haha, you got that right. well, I just tried using a different external power source (the first time was a usb connection, and I read about the grounding issues, so I used an ac adapter) and winpic800 picked it up, wrote, and verified the chip successfully. However, when I tried to verify it after programming, it failed reading all 0's, so I'm hoping it wrote and maybe there's some sort of read-lock on it or something, I'll hook up the circuit later today to test.

Spend a piddly $40 and get yourself a PICkit2 or one of the clones (). Your sanity will thank you.

 

[n8thegr8]

true, but a piddly $40 coulda bought the project I'm building, or one of the batteries for my ebike conversion. I don't like spending money if I don't have to...

 

[richard.c]

How many hours spent building duff programmers, all the cost of the parts, the batteries, cables, power supplies, the time and expense of all the trips to the component shop etc - does it take to equal $40 dollars .

Get a proper Pickit2 or one of a supported development units like the Junebug.

Been there, done that , thankfully now got the Pickit2 !!

 

[blueroomelectronics]

How many hours spent building duff programmers, all the cost of the parts, the batteries, cables, power supplies, the time and expense of all the trips to the component shop etc - does it take to equal $40 dollars .

Get a proper Pickit2 or one of a supported development units like the Junebug.

Been there, done that , thankfully now got the Pickit2 !!

True, if the JDM was a reliable programmer I probably would have made a kit.

 

[n8thegr8]

well it worked. The external power supply did the trick, the reason it read back 0's is because the code is protected. I prefer piklab under linux over any other software by far. So yup, saved me $40, wooo! Thanks anyways.

 

[blinky465]

Programming software

I too had problems getting my hex file onto a PIC18F2455.
I had a DIY programmer and from other forum posts, I think it might be one of the dodgy Chinese pirates (I bought it 2nd-hand from eBay so don't know exactly where it came from). I found an app called DonkeyProg which works with all my 16F and 18F PIC chips whereas no other burning software worked.

I have since bought a genuine programmer and agree with the earlier posters on this thread - you need to be confident that your programmer works, otherwise trying to debug your own circuits can be a nightmare!!