17 Jul
2023
17 Jul
'23
5:24 a.m.
Common DSO trigger problems experienced by a novice are:
1) Trigger position is off the screen. The trigger position relative to the
current visible capture is typically shown somewhere on the screen - often
at the top of the screen. Reduce the horizontal resolution to something
like 10 ms/division and then scroll the trigger position to be in the exact
centre of the screen and then increase the horizontal resolution to
something suitable e.g 500 ns/division. Typically the DSO will keep the
trigger position centred if you had it close enough to the centre position
before increasing the horizontal resolution.
2) The horizontal resolution is set so that the pulse is invisible. For
example 1 ms/division for a 10 ns pulse.
3) Triggering on the wrong channel.
4) Trigger level above or below the signal.
5) Trigger mode set to "Auto" as opposed to "Normal" or
"Single" causing a
momentary display of the triggered signal which is immediately overwritten
by the current signal.
Tom Hunter
On Mon, Jul 17, 2023 at 1:14 AM Rob Jarratt via cctalk <
cctalk(a)classiccmp.org> wrote:
I used a logic analyser to check the 8228 and it does
appear to be working
as expected as can be seen here
https://rjarratt.files.wordpress.com/2023/07/8228-operation.jpg. The
labels are not very clear, but the 3rd from top is the WR input and the 4th
from top is the I/O W output. So it does look like it is working.
The odd thing is that I can't pick this up with my DSO. I have tried
messing with the trigger, but I just can't pick up anything that shows I/O
W going low. I am using -ve edge triggers. I have tried a pulse trigger
with a width >20ns and I have tried nth edge trigger, neither of the latter
two ever trigger. Obviously it is my method that is wrong, but I really
don't know what it is about my method that is wrong. Are there any common
mistakes that novices make?
Thanks
