Search found 90 matches

by ijor
Sat Dec 01, 2018 12:31 pm
Forum: HARDWARE DISCUSSIONS
Topic: Project: HDMI/DVI out for STFM
Replies: 526
Views: 64151

Re: Project: HDMI/DVI out for STFM

I have just captured a video of running this. Also wanted to show you the warts and all process of getting to run this with the resetting and sometimes out of phase TOS message screens. Just uploading video so will post shortly. Icky, which chipset version you have on that machine? If you don't kno...
by ijor
Sat Dec 01, 2018 12:27 pm
Forum: HARDWARE DISCUSSIONS
Topic: Project: HDMI/DVI out for STFM
Replies: 526
Views: 64151

Re: Project: HDMI/DVI out for STFM

Thanks Icky. That odd boot screen is probably due to the shifter being in one resolution and TOS in another. I'm sure it will go away when the read issue is resolved. It might be better to run the program from the boot sector instead of from the AUTO folder. Much less chances that it would trigger ...
by ijor
Sat Dec 01, 2018 9:48 am
Forum: SOFTWARE PROGRAMMING & DISCUSSION
Topic: Exception vector oddity
Replies: 8
Views: 1736

Re: Exception vector oddity

... You can't reliably return from a bus or address error. The value of the PC pushed on the exception frame is not exact. This is also described on the 68000 manual. Sorry, but that's not correct. Me, as TOS expert, and who disassembled complete TOS 1.04 , 1.62 and 2.06 know that reliable return h...
by ijor
Sat Dec 01, 2018 9:34 am
Forum: HARDWARE DISCUSSIONS
Topic: Project: HDMI/DVI out for STFM
Replies: 526
Views: 64151

Re: Project: HDMI/DVI out for STFM

I guess the next most logical failure mode for this scenario is that R/W is not being driven high enough to be buffered by the '245s on the FPGA board (we have seen Icky's CS and it looks good to me). Not so sure this is very likely. If you would get a low RW, you would interpret it as a write cycl...
by ijor
Sat Dec 01, 2018 8:44 am
Forum: ALPHA DEVELOPMENT INFO
Topic: Cycle exact FPGA recreation
Replies: 13
Views: 2043

Re: Cycle exact FPGA recreation

I'm very curious what this could mean to the future of the STF Remake Project. I'm not really sure, because the suska ones were direct replacements for chips, MiST doesn't have a lot of signals as its all internal, so you can't really use these cores (AFAIK) with the stuff I am doing. The cores wer...
by ijor
Sat Dec 01, 2018 8:25 am
Forum: HARDWARE DISCUSSIONS
Topic: Project: HDMI/DVI out for STFM
Replies: 526
Views: 64151

Re: Project: HDMI/DVI out for STFM

I too have a LA not as many channels as troed. However I just need pointing in the right direction to help. So just point and click and I’ll see how I can help as with troed I can reproduce the problem. I would trace these signals: CLK_16MHZ CLK_8MHZ SHIFTER_CS LS373_LATCH DIR (at the 74ALVC164245 ...
by ijor
Sat Dec 01, 2018 8:14 am
Forum: HARDWARE DISCUSSIONS
Topic: Project: HDMI/DVI out for STFM
Replies: 526
Views: 64151

Re: Project: HDMI/DVI out for STFM

assign oe = (!cs) && rw; Are all these 3 signals directly connected to the FPGA external pins? These are the two D8 diagrams overlaid, in which you can see the real shifter begins to drive later and continue to drive later, a delay of about 12nS: This is expected, but shouldn't be relevant. What re...
by ijor
Fri Nov 30, 2018 11:48 pm
Forum: HARDWARE DISCUSSIONS
Topic: Project: HDMI/DVI out for STFM
Replies: 526
Views: 64151

Re: Project: HDMI/DVI out for STFM

This is amazing, thanks Ijor! I'm sure this is a smoking gun that will unravel the whole thing, although I don't yet understand how the shifter's bus driving behaviour can be influenced by a RAM read that comes *after* the shifter read cycle should have finished... I look forward to investigating. ...
by ijor
Fri Nov 30, 2018 9:20 pm
Forum: SOFTWARE PROGRAMMING & DISCUSSION
Topic: Exception vector oddity
Replies: 8
Views: 1736

Re: Exception vector oddity

I'm putting the finishing touches to a version of FORTH. It's rather easy to generate bus and address errors in bugged FORTH so I'm currently writing the code to intercept the exceptions. I have the exception handling working but there is an oddity. The M68K documentation I have states that excepti...
by ijor
Fri Nov 30, 2018 8:59 pm
Forum: HARDWARE DISCUSSIONS
Topic: Project: HDMI/DVI out for STFM
Replies: 526
Views: 64151

Re: Project: HDMI/DVI out for STFM

Hi, Smonson pointed me to this thread asking me if I could help with the problem ... Icky has generously donated his time to investigate the weird register reading behaviour with his oscilloscope. This image collects the most important signals into one graphic. I cannot, for the life of me, see wher...

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