Search found 124 matches

by Petari
Wed Jan 03, 2018 3:32 pm
Forum: SOFTWARE PROGRAMMING & DISCUSSION
Topic: Sideways updated
Replies: 0
Views: 49

Sideways updated

http://atari.8bitchip.info/SCRSH/sideways.html There is YT video and DL on page. Unfinished game from about 1991. But pretty well coded - 50 fps constant screen refresh. Based on Jamie Woodhouse development version. Added changes to make it playable as usual games - limited life count, losing life w...
by Petari
Wed Jan 03, 2018 1:23 pm
Forum: STF REMAKE PROJECT
Topic: Video output considerations
Replies: 23
Views: 426

Re: Video output considerations

Wouldn't it be easier to offload all this to a dedicated video chip? http://www.chrontel.com/product/detail/54# Certainly would be easier. And even more easy would be usage of mentioned Philips TV :D But then, where is the fun, where is learning of some things ? As usual, it can be solved in many w...
by Petari
Wed Jan 03, 2018 8:52 am
Forum: HARDWARE DISCUSSIONS
Topic: Project: HDMI/DVI out for STFM
Replies: 85
Views: 2471

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
Wed Jan 03, 2018 8:22 am
Forum: STF REMAKE PROJECT
Topic: Video output considerations
Replies: 23
Views: 426

Re: Video output considerations

Probably one method is to copy the video data from shifter (binary outputs) and use a PLD (assuming enough RAM) for frame buffer. Then the frame/ram buffer would be dual channel, so any refresh rate could be used, and is read from the buffer. Buffer could output at 100hz then for example. Yep. that...
by Petari
Tue Jan 02, 2018 3:00 pm
Forum: STF REMAKE PROJECT
Topic: Video output considerations
Replies: 23
Views: 426

Re: Video output considerations

I looked what TVs with Scart input are available at moment in EU. Here is what is not expensive: Philips 22PFS4031/12 FHD - it has Scart input + HDMI, DVI, all new DVB standards supported ... About 110-120 Euros . Of course, can serve as PC monitor too. USB connector for media playback, speakers. So...
by Petari
Tue Jan 02, 2018 12:58 pm
Forum: EVERYTHING ELSE
Topic: VHDL CACHE ?
Replies: 21
Views: 387

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: 387

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: 387

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
Mon Jan 01, 2018 11:42 am
Forum: SOFTWARE PROGRAMMING & DISCUSSION
Topic: Test/Demo SW for 50-60 Hz framerate conversion
Replies: 4
Views: 139

Re: Test/Demo SW for 50-60 Hz framerate conversion

Hi Simonson, and Happy New Year :D I seen that thread and practically same one at AF. As said here already, I don't think that I invented hot water. It is just that I like to go in some design with mine ideas, based on my long (30 years with ST) experience. And I think that exxos-s new ST motherboar...
by Petari
Sat Dec 30, 2017 8:41 pm
Forum: DISPLAYS & CONVERTERS
Topic: Atari ST Display Basics
Replies: 16
Views: 969

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...