Transistortester not working

[panoss]

I 've built the well known transistor tester but it 's not working.
With this firmware (I 'm using an ATMega8).



This is what it displays when I have nothing connected on the test points and press the button:


And this with a resistor connected (at the test points):


As you can see it does not really measure anything.

I have checked for cracks on tracks, shorts, cold solderings, anything. But haven't found any fault.
Any help is welcome.

(I 'm using a 4MHz crystal instead of 8MHz as per the original design. I 've added the frequency in the code)

[CDaniel]

You should try to find an 8MHz quartz and use the original code ...
And I don't see how option bits should be set , Atmega8 has CKDIV8 , clock divided by 8 or not

[panoss]

But this is the original code, I just added the frequency:

Code: [Select]

#define F_CPU 4000000UL

[CDaniel]

I mean the original hex provided . I don't use that system but after a change the program is recompiled and a different hex should result ... The compiler has to know what timings to change for the new frequency , pretty much everything

[panoss]

The result was the same with the original hex file (and other hex files I tried, e.g. this one).

[panoss]

Finally...it was a bad soldering...