Thanks for nothing Bart T!
It's not a homework question, unless you think someone who's 32 years old still has homework to do! Maybe I need to post a copy of my driver's license and passport to get a question answered!?
It's quite a sorry situation when that's the first and only response to someone asking for help! I've seen it before in forums all over, and sometimes it is obvious that a student is trolling to get free homework done, but I still think people should be given the benefit of the doubt.
Sorry if I sound pissed, but I am quite insulted by your response. I only wish I *did* get an education in any of this stuff when I was in school, then I wouldn't need to be asking for help.
FWIW - I'm not a newbie to emulation, digital circuits, or hardware.. (see www.pinmame.com for the majority of my work, plus some drivers for mame & fixing up a cpu core for mess(tms7000)) but the problem is it was all *self taught* in my limited spare time, and as such, there are glaring gaps in my understanding of certain things.
The question comes from sound board hardware for an Alvin G & Co. pinball machine which I am trying to improve the existing emulation I did. The current music plays too slowly, yet the samples play too fast. I've mucked around with guessing a combination of CPU Freq & FIRQ rate, and can't seem to get something quite right..
Having recently gotten access to a manual, I thought I'd try and figure it out from the schems. So I grabbed hold of the 6809 datasheet and did some reading, but I just don't understand the very brief explanation. That's where the question comes from...
I would very much appreciate some kind of help!
> > Was wondering if someone could help me understand how to calculate the timing
> > these 2 signals from the 6809.
> > Assuming the external crystal is set to drive the 6809 @ 8Mhz (which i believe
> > is the top speed the chip can go - on the 68B09), what would the frequency of
> > the E & Q lines be?
> > The hardware i'm looking at uses E to pulse a 4020 counter which eventually
> > toggles the FIRQ of the 6809, and obviously I'm trying to calculate the
> > freq. to generate the firq.
> > I've looked over the 6809 datasheet and just don't really follow it. I've
> > been good with timing in general, and those datasheets are not written to be
> > easily understandable unless you already get the concept! :)
> > So if someone could explain, not only the answer, but how I could have derived
> > the answer from looking at the datasheet, it would be greatly appreciated..
> > Thanks
> > -Steve