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32.084988MHz oscillator
Posted: 03 Nov 2019 21:28
by kodak80
On the Alpha we used a 32MHZ oscillator and though not ideal, it worked but ran a bit slower.
Just wondering if this will be the same on the H4 board? Could we use a 32MHZ OSC or does it have to be the Atari specific one? I have some 32.0MHZ OSC and need to know if I can use these or need to purchase from your store.
Re: 32.084988MHz oscillator
Posted: 03 Nov 2019 21:34
by exxos
You can use other oscs like 32MHz, but things will run slower like you say. Likely some demos may not work etc either. The 32.084988Mhz is 8.021247Mhz which I think Troed said was the best value to use.
Re: 32.084988MHz oscillator
Posted: 03 Nov 2019 21:37
by kodak80
So for the initial build and testing, I could get away with a 32.0MHZ one and it would show slower performance like the Alpha. Thanks for confirming. Will get the 32.084988MHz oscillator later once I have a working board or two. :D
Re: 32.084988MHz oscillator
Posted: 28 Nov 2019 02:12
by chue
The 32.08s are not exactly easy to find so I was wondering if there was a way to change the frequency somehow. I did a little googling and found this:
https://www.eham.net/community/smf/inde ... #msg977819
In the Ham Radio world, they do what is called "pulling" a crystal to tweak the frequency. From the above post, it looks like a small capacitor placed in series should "pull" the crystal frequency up.
I'm unsure if what they are doing can be applied here. Perhaps someone with a scope is willing to put a 32 MHZ crystal and a cap in series and see if they can come up with 32.08xxx?
Re: 32.084988MHz oscillator
Posted: 28 Nov 2019 02:31
by PaulJ
chue wrote: 28 Nov 2019 02:12
The 32.08s are not exactly easy to find so I was wondering if there was a way to change the frequency somehow. I did a little googling and found this:
https://www.eham.net/community/smf/inde ... #msg977819
In the Ham Radio world, they do what is called "pulling" a crystal to tweak the frequency. From the above post, it looks like a small capacitor placed in series should "pull" the crystal frequency up.
I'm unsure if what they are doing can be applied here. Perhaps someone with a scope is willing to put a 32 MHZ crystal and a cap in series and see if they can come up with 32.08xxx?
I don't believe you would be able to pull it near enough not to mention its an osc so you have no access to the xtal.
Re: 32.084988MHz oscillator
Posted: 28 Nov 2019 03:49
by exxos
They not easy to find, its why I stock them in my store, and also why they expensive, because they cost a lot to obtain.
Re: 32.084988MHz oscillator
Posted: 28 Nov 2019 07:47
by rubber_jonnie
Just ordered mine from your new store 😁
32.215905 MHz oscillator
Posted: 02 Jan 2020 08:30
by Tomswork
Looking for advise for use on 60hz us tos versions. Can someone tell me does US tos set up the timing differently than the 50hz ones and if so does the clock need to be higher 32.215905 MHz for this arrangement
Tom
Happy new year
Re: 32.215905 MHz oscillator
Posted: 02 Jan 2020 15:01
by PaulJ
Tomswork wrote: 02 Jan 2020 08:30
Looking for advise for use on 60hz us tos versions. Can someone tell me does US tos set up the timing differently than the 50hz ones and if so does the clock need to be higher 32.215905 MHz for this arrangement
Tom
Happy new year
Nope, its a lower freq. It's 32.0424 mhz. Best Electronics sells the osc or xtal. Just google "atari best", there pretty extensive for most of their items and have limited hrs. Something like 1-5pm. :)
Re: 32.084988MHz oscillator
Posted: 02 Jan 2020 16:36
by czietz
Note that you can buy custom oscillators set to any frequency of your choice from Digikey for like 3-4 US dollars (+ shipping, obviously). Never tried it myself, though.