Strange problem...same program on 3 different 18m2's...only works on 1?

[juve021]

Just as the title says it, I have a fairly long interrupted program downloaded to 3 different 18m2 chips. When I insert each chip 1 by 1 into my circuit, only chip A seems to function correctly. I have re-downloaded the program numerous times to all 3 chips and its always that only chip A only works correctly. Chips B & C start and then both restart at the same point (a return from a gosub command?). The program does not use any sleep only pauses however I have not tied all unused inputs to ground via 10k resistors. Could this be the problem? If so then why is it only a problem on Chips B & C? Anyone else have this issue or have any input? Thanks, cheers!

 

[premelec]

No clue - however DO earth all inputs not used and DO use bypass capacitor ON the PICAXE V+ & V- AT the socket. Every chip has some slight differences and these things are meant to minimize their unwanted effects... Little glitches in the power supply line can cause you troubles...

 

[westaust55]

Please post your program and the schematic diagram.
There is insufficient information in your description. Is your circuit borderline in terms of operation/tolerances? We do not know without a schematic.
There can be minor variances between the same chips even when they meet the datasheet specs.
Do you have decoupling capacitors (100nF) to filter out the switching noise from within the IC’s and “bulk” capacitor around 47 to 100 uF electro/tantalum to help maintain the power supply if there are momentary surges in current demand.
All tell us then exactly where in your program (by label name) you believe the problem occurs.

 

[hippy]

Also are all the chips of the same firmware version ? There shouldn't be any difference to how the program behaves but it's one of those things which needs to be crossed off the list of possibilities.