Bad pic chips or ?

[MrDEB]

I have a 18f43k22 mounted and I programed it with a short bit of code.
I then finished soldering the switches in the board.
Go to program the chip and keep getting an error in memory.
Did this about 6 times and still won't accept the code.
Using a Hakio temp controlled iron
Maybe something I am missing? or maybe just a bad chip?

 

[tumbleweed]

or maybe just a bad chip?

That's very rare. It's usually the circuit that's to blame.

Exactly what error message are you getting?

This is the board with the software controlled on/off circuitry?
If so, you would have to keep the button depressed the whole time you tried to program it, which could be tricky.
Are you trying to power the board from the pickit2?
What does the board VDD measure?
You have switches on RB7 and RB6... are they loading the lines somehow? Did it work before you installed those?

Can the LCD be removed or is it soldered onto the pcb?

 

[MrDEB]

It is just the board and tactile switches. nothing else.
I programmed the chip at 5:30a but at 5:45 it would not work.
It says succesfully loaded but ?
Will get back to you but something about memory 00480

 

[MrDEB]

for some unknown reason it now works?
maybe it was too early in the morning---lol

 

[Dr_Doggy]

rooks like us always get the blown ones, check for solder short circuits and double clean the flux between cracks.

based on your last post you may find a bad connection on the header

 

[Visitor]

Imagine that.

 

[tumbleweed]

mrdeb-

Your board has two voltage nets... "VCC" which powers the pickit ICSP connector, MCLR, and the momentary pushbutton,
and "Power" which is the pic VDD (and output of the programmable turn on circuit).

You may have issues with this arrangement since you can have voltage on MCLR but no VDD, which is a no-no.
In order to enter ICSP programming mode, VDD must be present at least 100ns before the MCLR voltage.
Note that the pickit is always going to think that the chip is powered, even if it is not.

You'll have to take a jumper lead and connect the output of the ON/OFF slide/toggle switch ("VCC") to "Power" in order to program the chip.


(mrdeb was kind enough to share his schematic with me)

 

[Nigel Goodwin]

I have a 18f43k22 mounted and I programed it with a short bit of code.
I then finished soldering the switches in the board.
Go to program the chip and keep getting an error in memory.
Did this about 6 times and still won't accept the code.
Using a Hakio temp controlled iron
Maybe something I am missing? or maybe just a bad chip?

Bad PIC chips are pretty well unknown - it's almost certainly a hardware error, a software error, or both.

 

[Visitor]

I had an interesting problem a while back where I used a 5 position sip resistor for pull-ups on switches, configuration jumpers and /MCLR.

I had the boards assembled as part of test run for the viability of off-shore assembly. It was a proven design that had been thoroughly tested in the past, so my testing was limited. Tested the switches for operation (separately and both pressed at once), found everything to be working as expected, then installed the two option jumpers, and shipped the product.

The customer said that when they tried one of the the units, when both switches were pressed, it locked up, and pressing reset wouldn't clear the problem. They repeated the test on a second unit with the same result. What the heck. Proven design with a number of them working every day in the field.

After a lot of cruse words, head scratching and careful inspection, I found that the sip resistor packs were installed backwards.* The common terminal, instead of going to +5V, went to /MCLR, and one of the resistor terminals went to +5. Everything was OK with the two switches pressed, but the combination of the two jumpers shorted & two switches pressed brought /MCLR into the dis-allowed zone between HIGH and LOW, locking up the micro but good. Installing the sip In the right orientation solved the problem.


*Lesson learned: When having boards assembled, don't make any assumptions about what will be understood. The arrow indicating the sip common terminal on the board would seem to be a good indication to match up with the common terminal marking on the sip package, but it didn't work out that way. Every sip in the lot of boards was reversed.

 

[MrDEB]

I just discovered the ICSP pins from the pickit2 are really loose.
By pushing on one side of the icsp header it has no issues.
DUH!

 

[Dr_Doggy]

lol ask how i kno!