Re: Historical Analog Scope Triggering Techniques


Tom Gardner
 

Consider buying one of the £20 logic analysers that use a USB
interface and the PC's screen. That (8 bits, 24MS/s) should be more
than enough to debug that kind of logic.

Key advantages of an LA are complex triggering and filtering, so you
only see the interesting information, not all the clutter.

On 04/12/2020, Jeff Dutky <jeff.dutky@gmail.com> wrote:
Okay, this is all in line with what I've been thinking about: building a
little box that can raise a TTL output on various conditions like a specific
counter bit, or having a 16 bit input value between two selected values, or
when certain bits are set or cleared, etc. It seems like this would make all
kinds of things visible on a simple analog scope at relatively little cost
(assuming that you don't want to do the triggering at clock rates much above
a few tens of MHz, of course).

One of the things that I was trying to do with these scopes, before I got
side tracked having to fix them, was to reverse engineer the digital
interface to a gas plasma display in an old laptop. Getting anything more
than a very general look at the display signals was very challenging,
especially since I didn't understand most of the scope's features very well,
but also because I just wasn't thinking clearly about how to trigger the
scope and one what. After working on these scopes for the past month I think
I'm beginning to get a better feel for what they can do and how they should
be used.

-- Jeff Dutky





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