Problem with PIC16F87

[aratti]

TRISB=%00000100

From your code you have portB.2 set as an input but it seems not used. Is this input pin floating?

Al.

[The Master]

Acetronics: The fuses are set in micropro (the software that programs the chip). I will try adding all of the other lines to the code though.

aratti: portB.2 is used as a serial input. Its not used in this test code but it will be eventually

[Acetronics2]

The fuses are set in micropro (the software that programs the chip)

Ayayaye ... Quel Malheur !!!

. I will try adding all of the other lines to the code though.

I do recommend you to succed adding those lines ... humour !

Alain

[The Master]

Ive tried adding those lines. It wouldnt compile with the first 3 so i commented those out. Its still not working properly. It does seem like its trying to work now and for a few seconds the lights flash at the right speed then they will start to hang in 1 state or flash rapidly.

I think ive seen a chip do this before when the supply cable is faulty but ive replaced that. The PSU is one i always use for things like this and is working properly, there are capacitors on the board and ive even tried adding an extra external capacitor

Im going to breadboard the circuit up with only an LED connected to see if i can get it working. Is there anything else i can check?

[The Master]

Ive found the problem. I thought a bit more about the faulty supply thing. Ive got a 555 on the same board. I tried removing it and the PIC seems to be working fine now.

Ive uploaded the schematic of the 555 part of the circuit. I know that works because ive checked it with the breadboarded version that i still have. The question is how can that affect the PIC part of the circuit?

[Acetronics2]

Hi,

I thought it was a 16F88 ... sorry !

Did you install the 0.1µF close to the '87 supply Pins ( between pins is best ! ) ... and a 10µF+ Tantalum as close as possible ???

Some decoupling might be also necessary for the 555 : there are well known current spikes while the output stage toggles ... or try a CMOS 555 !

Alain

[The Master]

I think i have a 10nF cap right at the side of the chip. Its as close as i can get it. There is also a 100uF cap right after the regulator. Theres also an audio circuit that connects to it which has a pair of 1000uF caps on i think (they are at least 100uF). It doesnt make any difference wether or not that circuit is attached.

I didnt use a CMOS 555 because i read somewhere that they wouldnt be suitable for this circuit.