Alright, here's a cleaned up (TOS 3.x/4.x/STBOOK stuff etc removed - I hope I got the sections right) startup.S from the TOS source code package: _main: /* disable the interrupts */ /* this is useless on cold boot, */ /* but it matters for software reset */ move #$2700,sr reset /* reset all hardware...

exxos wrote: ↑Tue Sep 18, 2018 6:32 pm

troed wrote: ↑Tue Sep 18, 2018 6:29 pm I'm confused by this being connected to BR.

Its a missing pull up resistor on BR & BGACK.

Yes. But both the pullup fixes are connected to BR, none of them to BGACK

exxos wrote: ↑Tue Sep 18, 2018 6:23 pm Bodge resistor 1..... 2.2K between the 2 circled points on back of CPU socket...

I'm confused by this being connected to BR.

Forgottenmyname wrote: ↑Tue Sep 18, 2018 5:11 pm I might make a new cable with hsync and hsync. Would everything else be the same minus the comp sync obviously

Measure them at the monitor port first But yeah, if they're ok there then you should have a stable image and maybe csync for some reason is off.

As of today I still get the rolling screen after applying the sync mod on U51. The Glue is still sending out 15khz on 37 and 60hz on 38. What do you have on the monitor port then? If HSYNC and VSYNC are steady at 15kHz and 60Hz you should not have a rolling screen ... unless your TV cannot handle 6...

exxos wrote: ↑Tue Sep 18, 2018 1:37 pm Can someone post the source file here ? Would be even better if someone could maybe label up exactly what is going on in the startup code step by step.

Yeah I had that thought yesterday when looking through it, just need to manually remove all ifdef:ed code only valid for TT/Falcon.

Forgottenmyname wrote: ↑Tue Sep 18, 2018 11:08 am BOMBS, we have bombs!

Alright! We're done. That's the most common ST screen anyway

That's pretty much what needs to be known.

startup.S in the re-created TOS 2.06/3.06 source code package is where this can be read in assembly code.

Icky wrote: ↑Mon Sep 17, 2018 8:26 pm I am getting 15.6kHz and 50Hz out of the Glue. It initially is 60Hz then immediately goes to 50Hz as mentioned by Troed.

That means ... *drumroll* ... that you have TOS execution. Lots and lots of instructions have done what they're supposed to

Forgottenmyname wrote: ↑Mon Sep 17, 2018 6:55 pm I did see 15Khz and 60Khz out of the Glue.

Assuming you have a PAL TOS, that means TOS didn't execute and/or the machine is being kept in RESET. One of the first things it does is to set 50Hz.

It does mean GLUE is working as it should