Project: HDMI/DVI out for STFM

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Icky
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Re: Project: HDMI/DVI out for STFM

Post by Icky » Wed Dec 05, 2018 11:37 pm

exxos wrote:
Wed Dec 05, 2018 11:35 pm
Icky, did you try a 4700uF across the shifter power rails ?
Currently have a 1000uF across the rails.

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Icky
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Re: Project: HDMI/DVI out for STFM

Post by Icky » Wed Dec 05, 2018 11:43 pm

So any voltage for me above 4.3V up to 5V and the board resets. I didn’t go any higher.

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Re: Project: HDMI/DVI out for STFM

Post by exxos » Wed Dec 05, 2018 11:44 pm

Icky wrote:
Wed Dec 05, 2018 11:37 pm
exxos wrote:
Wed Dec 05, 2018 11:35 pm
Icky, did you try a 4700uF across the shifter power rails ?
Currently have a 1000uF across the rails.
Staring to sound like ringing or noise on a signal somewhere. Or indeed gnd bound across the FPGA board s even,
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
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Smonson
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Re: Project: HDMI/DVI out for STFM

Post by Smonson » Wed Dec 05, 2018 11:55 pm

This gives me hope that I might be able to reproduce the issue here, by using a different power supply. Excellent!

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Icky
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Re: Project: HDMI/DVI out for STFM

Post by Icky » Thu Dec 06, 2018 12:00 am

Would be interesting to see how troed’s behaves at different voltages. See if he can replicate the same behaviour I am experiencing.

Still at 4.3V and on 5th loop now in GEMBench and no resets.

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Re: Project: HDMI/DVI out for STFM

Post by exxos » Thu Dec 06, 2018 12:19 am

Can you measure the voltage from the PSU 0v to 0v on the HDMI connector ( or somewhere as far up the board as possible) ?
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxoshost.co.uk/atari/last/storenew/ - All my hardware mods for sale - Please help support by making a purchase.

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Re: Project: HDMI/DVI out for STFM

Post by Icky » Thu Dec 06, 2018 7:41 am

exxos wrote:
Thu Dec 06, 2018 12:19 am
Can you measure the voltage from the PSU 0v to 0v on the HDMI connector ( or somewhere as far up the board as possible) ?
I did not get to this last night. CPU failed on my PC. Am not doing well with several PSU issues last month and now CPU failure this month.

I should get time to look at this tonight.

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Smonson
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Re: Project: HDMI/DVI out for STFM

Post by Smonson » Thu Dec 06, 2018 9:14 am

Sorry to hear about your CPU Icky. That really sucks.

Also I ran my machine on an ATX PSU at 5.06v for over fifteen minutes, but unfortunately didn't experience a single bad read. Ah, well.

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Re: Project: HDMI/DVI out for STFM

Post by tuxie » Thu Dec 06, 2018 9:49 am

Did someone check the ground ? Check how stable the ground against the ground on the PSU directly is ? We found very often a lot of mistakes with the ground. For example when the ground is not stable enough then the logic pulls the ground high and when the level of the ground signal goes over a specific value then the logic cant recognize a Zero Value anymore.

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Re: Project: HDMI/DVI out for STFM

Post by Smonson » Thu Dec 06, 2018 10:00 am

I measured a differential of around -4 millivolts between the FPGA board to the chassis ground (measured off the big electrolytic near the power supply). Not too bad considering the whole mod draws a lot of current (over 300mA).

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