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SX64 compatibility

Open Flexmaen opened this issue 1 year ago • 4 comments

The update to Version 3.10j improved the C128 compatibility signifigantly and I didnt have any issues yet. However my Ultimate 2 won't work on the SX64 from start.

Flexmaen avatar Oct 16 '23 08:10 Flexmaen

NTSC or PAL SX-64?

My 1541 Ultimate II (non plus) works fine with my PAL SX-64. Both 3.10j and the new 3.11 firmware. You might want to try carefully cleaning the edge connector of both the U1541 and the cartridge slot using de-oxit or similar. Good electrical contact is needed, especially because the SX-64 has a longer internal extender ribbon cable between the mainboard / daughter board and the cart slot.

Also, you could try changing the timing settings in the U1541 using 'Shift+F2' menu -> 'C64 and Cartridge Settings' -> 'CPU Addr valid after PHI2' and 'CPU Addr valid after PHI1'. My SX-64 works well with both of these values set to '200ns'.

You'll probably need to change these values using a C64 or C128 if the U1541 doesn't work at all on the SX-64, then move the cart over once you have saved these settings to flash using 'Shift+Run/Stop'.

If this doesn't help, you may want to investigate the condition of the cartridge port edge connector as well as the internal ribbon cable and the connection header on the mainboard / daughter board.

cybern0id avatar Jan 11 '24 02:01 cybern0id

@Flexmaen : Issue reports like: "It doesn't work" are not too useful. The issue should at least have a description of the observed behavior. What happens, when does it happen, what should happen instead; etc. Also what machine type you are using, indeed: Is it PAL or NTSC?

@cybern0id : This issue is probably related to garbled characters in the menu. It is a common misunderstanding that the PHI2/PHI1 settings have anything to do with this. The PHI2/PHI1 settings determine the timing for serving cartridges. The garbled menu characters are related to the cartridge master timing, thus when the Ultimate is acting like the CPU on the address/data bus. The only parameter that has influence on this is the 'PHI2 edge recovery', which is a more general setting.

GideonZ avatar Jan 11 '24 07:01 GideonZ

@GideonZ Ah, wow, thanks, I completely misunderstood. So these timings are for emulated cartridges in the U1541? I assumed the change in timings affected the menu when pressing the U1541 menu button because in my own experience, changing the PHI timings to slower speeds fixed the garbled screen when pressing the menu button. But this must have been coincidence due to my troubleshooting also involving cleaning the cartridge connectors at the same time. Sorry for the noise and bad advice!

cybern0id avatar Jan 11 '24 07:01 cybern0id

@GideonZ Hi Gideon! Sorry for the inaccurate error description. The problem (on my PAL SX-64) was that moving through the menu regularly crashed if it worked at all. And also starting programs did not work a single time. Thanks to your comment I tried setting PHI2 edge recovery to "enabled" and now it seems to work!

The thing with the firmware updates is: If you have "only" a C128 or SX64 I wouldn't recommend trying to change the firmware. It happened to me more than once that I needed a "regular" C64 in order to get the 1541-U2 working on the other devices again. Be it some settings or the version in general...

That said, it is still is so great to get a new firmware with even new functions after all that time! Finally also working on all my devices! I cannot judge if it is a big deal or just a minor thing to make firmware changes more relialble on non-standard-C64s, but if I can help with testing, just let me know.

Flexmaen avatar Jan 11 '24 12:01 Flexmaen