PIC18F14K50 MCLR problem

[russk2txb]

I didn't get an answer on this question before, maybe a poor subject. But this is serious for me. I cannot program the chip. CCS load will not read the chip ID. And it looks to me like there is a problem with the MCLR pin. I am pulling MCLR high with 11k, but when I measure voltage on MCLR it is only .25 volts. Looks like MCLR is set as an output and pulling low. First I thought I had a bad PIC, but just put in a new one and same problem.

I read the data sheet and it says that high voltage programming is always available by applying VIHH to MCLR. But nowhere does it specify what VIHH is. I guess it might be same as VPP, but ??? In any case, should not the device ID be readable?

I have the latest CcsLoad and firmware (versions 4.037 and 2.93 and hardware revision 2).

Has anyone else run into this problem. Or does anyone have a suggestion as to what could be wrong?

Thank you, Russ

[PCM programmer]

You didn't get an answer because we don't have a solution. It's something
that CCS will have to fix.

But here is a possible fix:
http://www.ccsinfo.com/forum/viewtopic.php?t=47769

I recommend getting a backup programmer. The Pickit 3 supports
the 18F14K50:

Bare Pickit 3:
http://search.digikey.com/scripts/DkSearch/dksus.dll?KeyWords=PG164130
You may also want to buy this connector kit:
http://search.digikey.com/scripts/DkSearch/dksus.dll?keywords=AC164110

The 6-pin connectors on CCS and Pickit 3 appear to have the same pinout:
http://www.ccsinfo.com/faq.php?page=connect_icd
http://ww1.microchip.com/downloads/en/DeviceDoc/DS-51792B.pdf

Using it with CCS:
http://www.ccsinfo.com/forum/viewtopic.php?t=46740

[temtronic]

It might help if you said what programmer you're using.

I use the Picstart plus, some use Pickit 2 ,some pickit3. I've heard of horror stories of trying to use the pickit3.....

[russk2txb]

I'm using the U64 programmer. I guess I thought that could be figured out because I mentioned CCS Load program. Does anyone still use the U40? Mine died over a year ago.

So this looks somewhat like problems other people are having, but slightly different. One guy was getting the wrong ID, but my programmer cannot read the ID at all. It seems like something different has to be done with MCLR in order to read the ID. Of course I can't even try to program it if the ID read fails. I guess monday I will have to call CCS and see what the scoop is.

Thanks to all for the comments.

Russ

[pebbert9]

I had a programming problem which cropped up about 2 months ago after an update.

I had erase EEPROM disabled in ccsload and it refused to program my chip.

Once I enabled erase EEPROM my problem went away.

I am currently programming the PIC18F14K50 without a problem using the latest version of the software.

[temtronic]

Russ, you shouldn't assume anything...'CCSload' to me just meant CCS's version of using ICSP to access a PIC. I've never read anything about it, so I wouldn't know it was specific to the U64 programmer.
Hay, when I started using PICs 25 years ago(sigh)..I cobbled a handful of parts to make programmers...finally bought a real one(18 years ago ?)a PicstartPlus ,now have two.
I also never use 'debuggers'...the real world is my test jig !

[russk2txb]

Pebbert9, thanks for the advice. But Erase EEPROM was already enabled. I did click the 'set to defaults' button and it enabled 'erase as little memory as necessary', but it makes no difference.

I did finally realize that MCLR being low is not the probem. If the programmer is not connected, or if it is and 'Run Program' has been clicked, then MCLR goes high.

But I finally was able to read the device ID. According to the data sheet:

[Douglas Kennedy]

I'm no longer sure as to what the MCLR pull up resistor value should be. I use 4.7k on the newer chips but used to use 47k years ago on the old chips that programmed much slower.