OricExos - making the impossible

Want to discuss about Demos on the Oric, here you are !
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Chema
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Re: OricExos - making the impossible

Post by Chema » Mon Apr 15, 2019 5:06 pm

Amazing indeed! And totally crazy :)

Well done!

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Dbug
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Re: OricExos - making the impossible

Post by Dbug » Mon Apr 15, 2019 6:05 pm

11KB/s with full broadcast mode, that's kind of cool :)

I guess I will have to come up with some additional PictConv modes optimized to support split rendering or multi-color.

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Re: OricExos - making the impossible

Post by Symoon » Mon Apr 15, 2019 6:23 pm

This greyscale demo is amazing. Very smart example of a new usage!

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iss
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Re: OricExos - making the impossible

Post by iss » Thu Apr 18, 2019 9:47 pm

Annoying RAM Overlay (MAP signal) failure - interesting moments to watch are 00:02:50 and 00:04:40:


While Oric #3 is rock solid, after some time Oric #1 and #2 start to give errors when accessing addresses in the enabled RAM Overlay.
The explanation is clear - things get hot and this changes the timing of the MAP signal. I will add trimmers for easy adjusting so all work properly in (at-least) 24h burn test :).

One conclusion here:
Any device which need to work with the RAM Overlay with any Oric should allow adjustment of the MAP signal (period).

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Dbug
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Re: OricExos - making the impossible

Post by Dbug » Fri Apr 19, 2019 8:20 am

iss wrote:
Thu Apr 18, 2019 9:47 pm
One conclusion here:
Any device which need to work with the RAM Overlay with any Oric should allow adjustment of the MAP signal (period).
Is that maybe what the Microdisc RV1 is for?

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iss
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Re: OricExos - making the impossible

Post by iss » Fri Apr 19, 2019 9:52 am

Dbug wrote:
Fri Apr 19, 2019 8:20 am
Is that maybe what the Microdisc RV1 is for?
Yes, exactly in Microdisc RV1 does the job.

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Re: OricExos - making the impossible

Post by Godzil » Fri Apr 19, 2019 8:27 pm

If it is linked with the system warming, I would look for capacitors which could start to fail, or simply it is one of the RAM chip which is starting to fail.

You should test these ORICes independently with a long memory test to check if there is no chip that is on the verge of failing

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iss
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Re: OricExos - making the impossible

Post by iss » Fri Apr 19, 2019 8:57 pm

Wow, @Godzil welcome back!

It's not the RAM - the same test runs for hours without errors when accessing low addresses (i.e. 0000-C000), only if MAP is active then after some period of time fails start to happen. I'm using 74LS123 and the Cext are new and stable tantalum capacitors.
But as I said - adding trimmers solved the problem. Interesting is also that changing randomly CPU, RAM, ULA one can achieve working configuration, but this is just 'private case' solution - that's why I said in my previous post - for universal solution there should be a trimmer (or something with the same functionality ... more in my next HW project ;)).

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Re: OricExos - making the impossible

Post by Dbug » Sat Apr 20, 2019 8:25 am

Could you briefly explain what a "trimmer" is in this context? I assume it's not related to cutting branches on trees or making one's facial hair looking nice :D

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iss
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Re: OricExos - making the impossible

Post by iss » Sat Apr 20, 2019 9:05 am

:) It's trimpot or trimmer potentiometer
trimmer-pot.jpg
trimmer-pot.jpg (4.96 KiB) Viewed 256 times

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