Search found 2374 matches

by TmEE co.(TM)
Thu May 02, 2019 6:24 am
Forum: Mega/SegaCD
Topic: Questions on writing a new Mega CD emulator
Replies: 114
Views: 11506

Re: Questions on writing a new Mega CD emulator

Top address byte of DMA transfer is a page register so to say, only the lower two bytes actually increment with each transfer, thus the 128KB pages where transfers take place.
by TmEE co.(TM)
Thu May 02, 2019 6:21 am
Forum: Super 32X
Topic: Using 32x as a 3rd plane, possible?
Replies: 28
Views: 5525

Re: Using 32x as a 3rd plane, possible?

68K can certainly draw into the framebuffers but it is probably tens of times slower that SH2 and you can probably forget about things like scrolling etc. since they'll use up a lot of 68K time, every single pixel needs to be manually written to the framebuffers by CPU, there's no hardware blitter. ...
by TmEE co.(TM)
Wed May 01, 2019 8:46 am
Forum: Sound
Topic: Some beginner questions concerning YM2612
Replies: 24
Views: 3462

Re: Some beginner questions concerning YM2612

There is no initialization, the attack begins wherever last state left off. Only way to get maximum attenuation is to wait out the envelope, using fastest release to reduce the time needed. Only on chip reset the internal attenuation is at max attenuation, once first note begins all bets are off.
by TmEE co.(TM)
Wed May 01, 2019 3:36 am
Forum: Super 32X
Topic: Using 32x as a 3rd plane, possible?
Replies: 28
Views: 5525

Re: Using 32x as a 3rd plane, possible?

Motorola couldn't up the clocks and their chips started to lag behind others (intel, IBM etc.) who were getting faster and faster, their big flagship chips weren't competitive anymore and customers moved to new things. In the end they dropped 68k line and started doing PowerPC instead...
by TmEE co.(TM)
Tue Apr 30, 2019 2:18 pm
Forum: Super 32X
Topic: Using 32x as a 3rd plane, possible?
Replies: 28
Views: 5525

Re: Using 32x as a 3rd plane, possible?

68040 and 68060 are the pipelined 68k series CPUs.
by TmEE co.(TM)
Mon Apr 29, 2019 2:15 am
Forum: Sound
Topic: Some beginner questions concerning YM2612
Replies: 24
Views: 3462

Re: Some beginner questions concerning YM2612

Most of the info is found in this post and this thread in general : viewtopic.php?p=5716#p5716
by TmEE co.(TM)
Sat Apr 27, 2019 11:13 pm
Forum: Sound
Topic: Some beginner questions concerning YM2612
Replies: 24
Views: 3462

Re: Some beginner questions concerning YM2612

Attack is done with reverse logarithmic slope while other things are done with normal logarithmic slopes. The way envelopes progress is tied to couple LUTs, after every certain amount of samples according to one LUT and ADSR settings, a value from another LUT is added to the attenuation value. Attac...
by TmEE co.(TM)
Sat Apr 27, 2019 11:01 pm
Forum: Mega/SegaCD
Topic: Questions on writing a new Mega CD emulator
Replies: 114
Views: 11506

Re: Questions on writing a new Mega CD emulator

The CD section clock is 44100 * 384 = 16934400Hz
by TmEE co.(TM)
Wed Apr 24, 2019 10:40 pm
Forum: Demos
Topic: MD-NICCC - a 3D Mega Drive experience by TiTAN
Replies: 56
Views: 6979

Re: MD-NICCC - a 3D Mega Drive experience by TiTAN

MD and SNES VRAM bandwidths are very similar in H256, though in H320 MD will pull ahead a bit and on DMA bandwidth alone both should be fairly similar, within 10% probably, be them both in 50 or in 60Hz. But here we see more than twice speed difference.
by TmEE co.(TM)
Wed Apr 24, 2019 3:31 am
Forum: Demos
Topic: MD-NICCC - a 3D Mega Drive experience by TiTAN
Replies: 56
Views: 6979

Re: MD-NICCC - a 3D Mega Drive experience by TiTAN

I cannot understand how SNES version that uses SuperFX still runs muuuuuuuch slower....
by TmEE co.(TM)
Wed Apr 24, 2019 3:29 am
Forum: Super 32X
Topic: Using 32x as a 3rd plane, possible?
Replies: 28
Views: 5525

Re: Using 32x as a 3rd plane, possible?

When 32X is enabled the ROM is only in $880000 to $9FFFFF, the first 4MB no longer has ROM in it. See page 15 for more info : http://www.tmeeco.eu/SMD/32x_hardware_manual.pdf
by TmEE co.(TM)
Sat Apr 20, 2019 1:53 pm
Forum: Video Display Processor
Topic: Help scale and rotation sega genesis
Replies: 33
Views: 4840

Re: Help scale and rotation sega genesis

I don't actually know if there's one or few ideal moments in the sync period to do the switch since I haven't actually experimented with it. There will not be a moment that will produce exact line length so you will only get to choose between very off and little bit off. Real world tests are needed ...
by TmEE co.(TM)
Fri Apr 19, 2019 8:22 pm
Forum: Video Display Processor
Topic: Help scale and rotation sega genesis
Replies: 33
Views: 4840

Re: Help scale and rotation sega genesis

Even then, a line is still a line regardless of where it is in the frame. There's 262 lines in 60Hz and 313 lines in 50Hz, rest are border, blanking and sync. Lines themselves all consist of border, active part, blanking and sync aswell, and switch can happen in the sync portion. Composition of one ...
by TmEE co.(TM)
Fri Apr 19, 2019 7:45 pm
Forum: Video Display Processor
Topic: Help scale and rotation sega genesis
Replies: 33
Views: 4840

Re: Help scale and rotation sega genesis

Switch must happen not just in horizontal blank, it must be in horizontal sync position of the line. You do your switch at any line you desire during the frame, but the switch itself must happen in sync portion of the line you do it on.
by TmEE co.(TM)
Thu Apr 18, 2019 10:28 am
Forum: Video Display Processor
Topic: Help scale and rotation sega genesis
Replies: 33
Views: 4840

Re: Help scale and rotation sega genesis

Enabling/disabling display isn't gonna do anything with that, video line generation is an autonomous process that runs always and depends on if internal dot clock or EDCLK is used (bit7 or VDP register $07). in H256 (256 pixels + internal dot clock) all pixels are 10 MCLKs long, while in H320 (320 p...