sporniket wrote: ↑Tue Jan 11, 2022 10:07 am
(EDIT : yes, shameless self quoting of my work )
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
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 (429.68 KiB) Viewed 1866 times
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PXL_20220111_112742693.MP.jpg (329.3 KiB) Viewed 1866 times
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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.
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.
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.
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)
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.
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.