WD1772 Programming

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npomarede
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Re: WD1772 Programming

Postby npomarede » Tue Jul 28, 2015 5:48 pm

Hi
very nice demo, especially the whole source release as well as the demo toolchain :)

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DrCoolZic
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Re: WD1772 Programming

Postby DrCoolZic » Tue Jul 28, 2015 7:23 pm

and music is super cool :mrgreen:
I love it

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metalages
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Re: WD1772 Programming

Postby metalages » Mon Aug 17, 2015 8:03 am

Thanks :)

For the soundtrack, I kinda "reversed" and re-sequence this track https://www.youtube.com/watch?v=vTEgF49Vxew which I appreciate a lot.

I am happy to share the code.
About the FDC routine, it does not manage read errors (like re-step the track, shoe cleanning, things I understood Atari routine does...)
It perfectly works on my STe but it seems some people have troubles with it.
I am curious if it comes from the FDC routine in itself (that does not perform retry steps ?),
or if it comes from the main demo sequencing as I have interlaced sync effects with parts where loading are performed (and timing is quite tight).

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DrCoolZic
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Re: WD1772 Programming

Postby DrCoolZic » Mon Aug 17, 2015 8:47 pm

metalages wrote:Thanks :)

For the soundtrack, I kinda "reversed" and re-sequence this track https://www.youtube.com/watch?v=vTEgF49Vxew which I appreciate a lot.

I am happy to share the code.
About the FDC routine, it does not manage read errors (like re-step the track, shoe cleanning, things I understood Atari routine does...)
It perfectly works on my STe but it seems some people have troubles with it.
I am curious if it comes from the FDC routine in itself (that does not perform retry steps ?),
or if it comes from the main demo sequencing as I have interlaced sync effects with parts where loading are performed (and timing is quite tight).

Not mandatory retry on errors help a lot. From what I have seen error happen more often than we think.
In my FDC lib i retry 5 times total. If after 3 retry still not good I move the head to help pushing dust ...

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metalages
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Re: WD1772 Programming

Postby metalages » Wed Aug 26, 2015 6:58 am

Do you mean on CRC error ? => retry read sector command 3 times and if it does not work, clean the head by stepping the head and then retry 2 more times ?
About RNF error, if I well understand, FDC has ever tried 5 times (5 revolutions) => do you step the head in this case ?
To clean the head, do you perform something like step track -1, +2, -1 ? or -1, +1 ?

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DrCoolZic
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Re: WD1772 Programming

Postby DrCoolZic » Wed Aug 26, 2015 7:22 pm

metalages wrote:Do you mean on CRC error ? => retry read sector command 3 times and if it does not work, clean the head by stepping the head and then retry 2 more times ?

Yes exactly

About RNF error, if I well understand, FDC has ever tried 5 times (5 revolutions) => do you step the head in this case ?
To clean the head, do you perform something like step track -1, +2, -1 ? or -1, +1 ?

CRC error is when you do not read data block correctly
RNF error is when you do not read the header/id block correctly.
So you can probably do same action in both cases. But as you mention probability is lower on RNF
for cleaning I usually change head position by 5 steps in one operation so hopefully dust do not follow head and put it back to wanted position.

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metalages
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Re: WD1772 Programming

Postby metalages » Wed Aug 26, 2015 8:47 pm

Thank you for the details.
I'll have to try this strategy (just have to find time to implement it ;))


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