• Please review our updated Terms and Rules here

Old eprom programmer help.

samib71

Experienced Member
Joined
Jan 20, 2024
Messages
106
The blue arrow i can move it right or left hand side, were it should be on the middle?
 

daver2

10k Member
Joined
Jun 19, 2012
Messages
14,334
Location
UK - Worcester
Now, put the oscilloscope probe tip ON THE GROUND CLIP and post a photograph of the oscilloscope screen.

Dave
 

samib71

Experienced Member
Joined
Jan 20, 2024
Messages
106
Blye arrow on top of the screen.
 

Attachments

  • 17075828337416801514682589931554.jpg
    17075828337416801514682589931554.jpg
    862.1 KB · Views: 3

samib71

Experienced Member
Joined
Jan 20, 2024
Messages
106
Pin 20 z80 after playing with setings.
 

Attachments

  • 17075834589318355742314398959171.jpg
    17075834589318355742314398959171.jpg
    1.5 MB · Views: 3

daver2

10k Member
Joined
Jun 19, 2012
Messages
14,334
Location
UK - Worcester
Which is why I suggested connecting the tip of the oscilloscope probe to the ground clip in the first place.

Irrespective of what your oscilloscope has or has not, this will ALWAYS work...

I have just read the manual myself. Your oscilloscope only has AC or DC coupling. No ground setting.

Also, the specifications for the probes are pretty abysmal in X1 mode. Perhaps we ought to have them in X10 mode - providing the oscilloscope is smart enough to adjust the display for us...

Have a good evening.

Dave
 

samib71

Experienced Member
Joined
Jan 20, 2024
Messages
106
Hi dave i m back , how would you like me to the scope, i put V on 1v time(s ns) ?
I made a lots of tests yesterday and i confirm that there is a signal which is present on pin20 of z80, it can be visible if i put for exemple settings 500ns 100mv if i put 1v the signal becomes a straigt line.
 

Attachments

  • 17076439488298671651497460363348.jpg
    17076439488298671651497460363348.jpg
    1.5 MB · Views: 4

daver2

10k Member
Joined
Jun 19, 2012
Messages
14,334
Location
UK - Worcester
>>> I made a lots of tests yesterday and i confirm that there is a signal which is present on pin20 of z80, it can be visible if i put for exemple settings 500ns 100mv if i put 1v the signal becomes a straigt line.

What you are telling me is (effectively) that there is NO 'signal' on pin 20 of the Z80 apart from random noise...

This is why I suggested setting the Y sensitivity to 1 V/div and adjusting the 0V level to a sensible place so I can work out what the actual voltage is (I don't trust the numbers that are presented and I like to know where 0V actually is).

So, can you go back and do what I asked you to do in post #163 please?

Let us align the oscilloscope trace up so I know where 0V is - with some sensible reference (i.e. one major division up from the bottom of the screen with the sensitivity set to 1 V/div).

Dave
 
Top