Re: [CAD_CAM_EDM_DRO] Re: Pulse Gen

Jon,

I sent Mariss a message off list in which I tried to explain this same
issue. I suspect he is a bit naive when it comes to PC interfacing. The
sad truth is that the PC interrupt system is very flaky, even with
Linux.

Jeff

On Thu, 07 Dec 2000 14:34:26 -0600, you wrote:

>
>
>Mariss Freimanis wrote:
>
>> Hi,
>>
>> Jon, I respectfully disagree for two reasons:
>
>OK, in the specific sense that you were using this on an embedded system,
>where you decided how to set up the interrupt response, etc. then I agree,
>there is no problem. A lot of the people here are talking about using this
>on a PC, under Windows 95 or thereabouts, with little or no Real Time
>support. That is a definite problem, as interrupt service is really
>unpredictable in that environment.
>
>> 1) This is based on an idustrial product I originally designed about
>> 10 years ago. It was a dual axis pulse gen integrated with a Z80
>> computer on the same board to do the math. It was way too expensive
>> ($750) but several hundred were sold. It worked perfectly.
>>
>> 2) It doesn't matter when precisely you output the velocity update,
>> only that you update every interrupt. The data is "clocked" in on the
>> interrupt edge. You have the entire subsequent interrupt period to
>> present the next update.
>
>Jon
>