Search found 311 matches

by Petari
Wed Jan 03, 2018 8:52 am
Forum: HARDWARE DISCUSSIONS
Topic: Project: HDMI/DVI out for STFM
Replies: 507
Views: 53572

Re: Project: HDMI/DVI out for STFM

Hi-color displaying, so Spectrum 512, Photochrome and similar, then overscan are very timing sensitive. My simple vertical overscan with res. 320x273 needs testing of CPU speed for correct work on NTSC machines - because on them CPU clock is little different. Spectrum 512 normally shows same border ...
by Petari
Tue Jan 02, 2018 12:58 pm
Forum: EVERYTHING ELSE
Topic: VHDL CACHE ?
Replies: 21
Views: 4521

Re: VHDL CACHE ?

Well, I let that overclocking to you and troed. Same as with overclocking FDC chip for HD floppies - some can work fine at 16 MHz, some not. With aged machines it will be just worse. Time too look after that Altera Cyclone ...
by Petari
Tue Jan 02, 2018 12:39 pm
Forum: EVERYTHING ELSE
Topic: VHDL CACHE ?
Replies: 21
Views: 4521

Re: VHDL CACHE ?

I looked about SRAM prices. 4MB, 16 bit (so, good for some ST clone as main RAM) 55nS is about 20 Euros. 10nS v. is about 80 Euros, what is too much indeed. Overclocking MMU - but then it will break whole video generation - it will increase horizontal freq. of video and all other. And of course, it ...
by Petari
Tue Jan 02, 2018 8:31 am
Forum: EVERYTHING ELSE
Topic: VHDL CACHE ?
Replies: 21
Views: 4521

Re: VHDL CACHE ?

I think that clearing cache tag can be done smarter: when reset signal happens, you just set cache off global HW register - 1 bit . That will result in not accessing cache at all, so CPU works slower. In same moment start to delete tag cache, and when it is finished, you can set cache on. So, no nee...
by Petari
Sat Dec 30, 2017 8:41 pm
Forum: DISPLAYS & CONVERTERS
Topic: Atari ST Display Basics
Replies: 31
Views: 11567

Re: Atari ST Display Basics

This discussion about lack of modulator - actually, lack of color encoder circuit reminded me about what I seen in my time of servicing old computers, around 1983-95 . Secam was in use in practically whole Eastern block, so in Hungary too. Not in Yugoslavia (PAL) . But I did some TV upgrades in that...
by Petari
Sat Dec 30, 2017 8:21 pm
Forum: DISPLAYS & CONVERTERS
Topic: NEC MultiSync EA190M
Replies: 2
Views: 2229

Re: NEC MultiSync EA190M

... The only downside I see is that the image is a little bit out of focus, it would have been nice if the monitor had some sort of sharpness setting, but I cannot find one. Of course, there is no focus setting on LCD monitors. To get sharp picture from analog input with low res, you need to set wi...
by Petari
Sat Dec 30, 2017 5:26 pm
Forum: SOFTWARE PROGRAMMING & DISCUSSION
Topic: HDD drivers. How does it work?
Replies: 14
Views: 1905

Re: HDD drivers. How does it work?

HDDRIVER who ? :lol: Good work :dualthumbup:
by Petari
Fri Dec 29, 2017 6:48 pm
Forum: EVERYTHING ELSE
Topic: VHDL CACHE ?
Replies: 21
Views: 4521

Re: VHDL CACHE ?

Well, some people talked about doing tests about that cache reset (invalidate) - when blitter activates. So far nothing. Similar can be done for disk DMA too. It seems that I will need to do it myself ... Fill cache by reading some area multiple times, then blit there, or load from disk there some o...
by Petari
Fri Dec 29, 2017 12:08 pm
Forum: EVERYTHING ELSE
Topic: VHDL CACHE ?
Replies: 21
Views: 4521

Re: VHDL CACHE ?

It is called tag RAM - what stores which locations are cached - therefore you see 2 SRAM chips in Mega STE. Considering blitter: (and DMA too) - there is simply no sense to cache them. Goal is not to have faster writes in cache, because that will probably be not accessed immediately, so chances that...
by Petari
Fri Dec 29, 2017 7:06 am
Forum: SOFTWARE PROGRAMMING & DISCUSSION
Topic: Problem with autoboot.
Replies: 8
Views: 1447

Re: Problem with autoboot.

... It's not clear to me where it went wrong. Do you have any idea what was not correct? As always, I want to learn. ... Use some Hex editor/viewer to see that changes are not done at proper addresses, and not even proper values written. Additionally, what is at offset $3FA00 is not IDE code, but c...