My chip is ignoring my PC

[The Master]

Hi. Sorry to bother you all once again but im having more trouble with my circuit. Im using a MAX232 chip to connect a PC serial port to a PIC16F627. The data isnt getting to my PIC. Ive checked all the connections and they are all ok. Ive checked the pinouts and they are all correct. My PIC chip does work. It runs a startup sequence then waits for a serial input but it doesnt get there.

This all worked perfect on a breadboard the other day but now its the real PCB. Can anyone think of any common problems in this kind of setup that i might not have checked? Is there anything can give you to help you help me? (Schematic not available but i do have the PCB layout)

[mister_e]

better than nothing i guess.. post it and also post your code and .HEX file

[The Master]

Ok. The PCB looks a bit crowded so it might be hard to look at. Some components are under the PCB thats why they seem to overlap.

The code isnt the final version but it worked perfect on the breadboard tests

[mister_e]

Your .HEX says that you're using a XT osc... but your code says... DEFINE OSC 16... it has to be HS

MCLR is enable.. not sure you handle it on your PCB or if you're using it as i/o in your program.. not seen in your program 'till now...

Now you see some advantage to set the fuses in your code?

[The Master]

I have to set the fuses in my programmer. I do set them to what you said.

Anywho. I found the problem. I tried linking the serial output directly into the serial input (NO circuits at all) and it didnt work. Aparently ive blown my USB<>Serial adapter up earlier when my circuit started smoking. Ive tested it in a standard serial port and its working

Sorry to have bothered you but thanx for the output>input idea. Cant believe i didnt think of that before

[The Master]

Ive just done some checks and yesterday i successfully blew up:-

1 X MAX232 chip
2 X 1K Resistors (violently)
2 X PIC chips
1 X Tri-color LED
2 X Diodes
1 X USB<>Serial adapter

Not a bad day!

Im making 2 circuits and the other one is now working perfectly. Nothing has blown up yet. I did happen to order spare PIC chips, LEDs etc and i got boxes of 1000 resistors so that all ok but the Maplin store near me only stocks 2 of the MAX232 chips at a time and wont get anymore in till Jan

Does anyone have any interesting ways of removing a chip from a PCB? Unfortunately i didnt have any DIL sockets that fit the MAX232 so now i have to remove it. Anyone have a good way of getting chips out?

[Norbac]

Hi, the easiest way to verify to circuit (at least the max232 part) is to put a jumper between tx and rx pins (ttl section), so everything you write down to the PIC will be send it back to the computer, remember this is just to verify the max232 part. For the PIC section you must write a little code to turn on and off a pin every time the PIC receive a message from PC. At least this is what I do every time I want to be sure my hardware works correctly.

Regards