Customer's Problems

Customers' Problems

PIC Training & Development System:-

Problem	Solution
Hello Brunning Software !.. I cannot seem to program my 16F627a PIC in the plugboard. A 16F88 has no problems in programming. The 16F627A however always fails, unless it is located in the ZIF, or has a very small separation from it. Many thanks, B (UK)	Dear B, The plugboard has a relatively high capacitance between adjacent lines so if you make too many connections on the RB6 and RB7 inputs of the PIC this can affect the programming function. What happens is that the added capacitance couples the programming data pulses into the programming clock input which can cause spurious clock pulses. Tidy up your circuit to keep the leads as short as possible and try to use just one row of connections for each of RB6 and RB7. You should find this solves the problem but if not add a small amount of extra capacitance on the programming clock line. Adding 22pF from RB6 to ground makes the PIC tolerant of quite high plugboard capacitance but up to 50pF can be added. The latest XLP PICs are even faster so the P928-X version of the Brunning Software programmer drives the programming clock with a lower source impedance. This makes the system tolerant of quite high plugboard capacitance but even so care should be taken to keep the capacitance between RB6 and RB7 to a minimum. Best wishes, Peter Brunning
I have programmed a PIC16F627 wired into the plug board. Every thing went OK until I tried to use it. It did not work.	This can happen if another PIC is plugged into one of the ZIF sockets at the same time. What happens is both PICs are programmed correctly but when you read the configuration the values displayed will be all the zeros from both PICs so you may think your PIC is properly configured when it is not. The solution is obvious you must always ensure that only one PIC is being programmed.