STE video chip

Problems with your machine in general.
User avatar
Badwolf
Posts: 2231
Joined: Tue Nov 19, 2019 12:09 pm

Re: STE video chip

Post by Badwolf »

sporniket wrote: Tue Jan 11, 2022 10:07 am (EDIT : yes, shameless self quoting of my work :D )
No, thank you for doing that, as I had completely forgotten I had a copy of your repo here! :-)

BW
DFB1 Open source 50MHz 030 and TT-RAM accelerator for the Falcon
DSTB1 Open source 16Mhz 68k and AltRAM accelerator for the ST
Smalliermouse ST-optimised USB mouse adapter based on SmallyMouse2
FrontBench The Frontier: Elite 2 intro as a benchmark
Steve
Posts: 2570
Joined: Fri Sep 15, 2017 11:49 am

Re: STE video chip

Post by Steve »

Just testing an STe with the C301712-001 shifter and has a SN74F257 for 32mhz. This Machine was too unstable to run the 32mhz exxos booster. HC CPU installed.

Ch1 is on 32Mhz Ch2 was on 8Mhz CPU clock. Photos of how I wired it up too.

The 32mhz looks terrible doesn't it?

PXL_20220111_105516032.jpg
PXL_20220111_105516032.jpg (429.68 KiB) Viewed 1792 times
PXL_20220111_110024530.jpg
PXL_20220111_110024530.jpg (408.33 KiB) Viewed 1792 times
PXL_20220111_112742693.MP.jpg
PXL_20220111_112742693.MP.jpg (329.3 KiB) Viewed 1792 times
PXL_20220111_112137236.jpg
PXL_20220111_112137236.jpg (345.14 KiB) Viewed 1792 times
User avatar
exxos
Site Admin
Site Admin
Posts: 23497
Joined: Wed Aug 16, 2017 11:19 pm
Location: UK
Contact:

Re: STE video chip

Post by exxos »

Are you using x10 probe ?

EDIT:

Eitherway it looks out of sync with the C301712, which is what I documented. So you need the other chip most likely.
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
Steve
Posts: 2570
Joined: Fri Sep 15, 2017 11:49 am

Re: STE video chip

Post by Steve »

Yes,

Here is one in 1X:

PXL_20220111_113526809.MP.jpg
PXL_20220111_113526809.MP.jpg (341.3 KiB) Viewed 1781 times
Steve
Posts: 2570
Joined: Fri Sep 15, 2017 11:49 am

Re: STE video chip

Post by Steve »

@exxos The SN74F257 only outputs 2.5v clock, is that correct? Would it be better if it outputted 5v?
User avatar
exxos
Site Admin
Site Admin
Posts: 23497
Joined: Wed Aug 16, 2017 11:19 pm
Location: UK
Contact:

Re: STE video chip

Post by exxos »

Use the cartridge port metalwork for the ground and see if that helps, that is what I used.
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
User avatar
exxos
Site Admin
Site Admin
Posts: 23497
Joined: Wed Aug 16, 2017 11:19 pm
Location: UK
Contact:

Re: STE video chip

Post by exxos »

Steve wrote: Tue Jan 11, 2022 1:13 pm @exxos The SN74F257 only outputs 2.5v clock, is that correct? Would it be better if it outputted 5v?
Yes, but in the MHz range the voltage drops anyway. The buffered clock on the CPU goes from like 1-2V, its a wonder it even works at that. But the loading of the probes taints results because of all the loading. It could be the probes you are using causing the issue. It is a bit of a minefield unfortunately.
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
User avatar
sporniket
Posts: 956
Joined: Sat Sep 26, 2020 9:12 pm
Location: France
Contact:

Re: STE video chip

Post by sporniket »

Steve wrote: Tue Jan 11, 2022 12:47 pm Just testing an STe with the C301712-001 shifter and has a SN74F257 for 32mhz. This Machine was too unstable to run the 32mhz exxos booster. HC CPU installed.

Ch1 is on 32Mhz Ch2 was on 8Mhz CPU clock. Photos of how I wired it up too.

The 32mhz looks terrible doesn't it?
The SN74F257 select the clock source (for the genlock), your motherboard seems to be a PAL system as I don't see U402. So for a starter the 32Mhz clock is not a signal straight from an oscillator, which may not help for a booster ?
sporniket wrote: Tue Jan 11, 2022 10:07 am The "MC" is proxyed by the selector U405(p 21 of my schematics), that select between a "32MHz" clock, either by a simple 32MHz oscillator on non-PAL systems (the exact frequency depends whether the it is for NTSC or not), or a 32 MHz oscillateur modulated by a line phase generated by a sub-carrier clock for PAL systems (see p.8), either by external clock (genlock) from the video port (see p. 21)

(EDIT : yes, shameless self quoting of my work :D )
User avatar
exxos
Site Admin
Site Admin
Posts: 23497
Joined: Wed Aug 16, 2017 11:19 pm
Location: UK
Contact:

Re: STE video chip

Post by exxos »

sporniket wrote: Tue Jan 11, 2022 1:20 pm The SN74F257 select the clock source (for the genlock), your motherboard seems to be a PAL system as I don't see U402. So for a starter the 32Mhz clock is not a signal straight from an oscillator, which may not help for a booster ?
The 32Mhz clock is buffered via the F257 which is what the booster has always used. Using direct from the osc probably won't work.

Steve has the "buggy" shifter which causes problems on my machine. So there is nothing else to investigate other than swapping it.
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
User avatar
sporniket
Posts: 956
Joined: Sat Sep 26, 2020 9:12 pm
Location: France
Contact:

Re: STE video chip

Post by sporniket »

exxos wrote: Tue Jan 11, 2022 1:28 pm
sporniket wrote: Tue Jan 11, 2022 1:20 pm The SN74F257 select the clock source (for the genlock), your motherboard seems to be a PAL system as I don't see U402. So for a starter the 32Mhz clock is not a signal straight from an oscillator, which may not help for a booster ?
The 32Mhz clock is buffered via the F257 which is what the booster has always used. Using direct from the osc probably won't work.

Steve has the "buggy" shifter which causes problems on my machine. So there is nothing else to investigate other than swapping it.
Thanks for the answers
Post Reply

Return to “HARDWARE ISSUES”