Search found 2378 matches

by TmEE co.(TM)
Mon Nov 18, 2019 9:42 pm
Forum: Megadrive/Genesis
Topic: Noob questions: DEFINITIVE info about Z80 BUSREQ, RESET?
Replies: 28
Views: 4919

Re: Noob questions: DEFINITIVE info about Z80 BUSREQ, RESET?

I haven't had any issues by doing a shorter than 192 cycle reset, but I always explicitly zero out all the YM registers and it seems internal state is also fine.
by TmEE co.(TM)
Fri Nov 15, 2019 12:53 pm
Forum: Megadrive/Genesis
Topic: DMA and FIFO
Replies: 11
Views: 2052

Re: DMA and FIFO

68K User manual suggests it is based on bus cycles rather than instruction cycles, I got the impression you can get the bus while an instruction is still halfway done. The processor asserts BG as soon as possible. Normally, this process immediately follows internal synchronization, except when the p...
by TmEE co.(TM)
Thu Nov 14, 2019 12:48 am
Forum: Video Display Processor
Topic: Upload speed on display time
Replies: 2
Views: 201

Re: Upload speed on display time

There's 16 or 18 access slots spread around one line during rendering, depending on 256 or 320 pixel mode, each capable of accepting one byte so 16 or 18 bytes are possible to transfer in best case during a line. 4x 68K cycles is 3.5 pixels, these access slots come in triplets that are 16 pixels apa...
by TmEE co.(TM)
Sun Oct 27, 2019 3:33 pm
Forum: Cartridge
Topic: Designing MD sdcard flashcart for fun, advice?
Replies: 7
Views: 839

Re: Designing MD sdcard flashcart for fun, advice?

If it is a proper NOR flash it'll take more than 100k writes before the flash fails. Overall the idea looks doable but I'm not sure if you can cleanly supply NOPs to the 68K and later get it execute something more useful. If I were you I'd pull !MRES low (this signal you can drive yourself, but only...
by TmEE co.(TM)
Thu Oct 03, 2019 7:18 pm
Forum: Controls
Topic: New device letters
Replies: 20
Views: 2186

Re: New device letters

Ok, so you support the Saturn stuff in your game ? How would the MD port pins be connected to the Saturn port ? I'm not sure any standard exists...
by TmEE co.(TM)
Sun Sep 29, 2019 11:42 am
Forum: Controls
Topic: New device letters
Replies: 20
Views: 2186

Re: New device letters

Use lowercase letters too not just uppercase ones, or perhaps just set the top bit to show it is saturn peripheral and not MD.
by TmEE co.(TM)
Mon Sep 23, 2019 5:22 pm
Forum: Demos
Topic: Hyrule in Megadrive/Genesis
Replies: 14
Views: 3337

Re: Hyrule in Megadrive/Genesis

Atmosphere of mars is just incredibly thin, roughly 100x thinner than earth. If it was 100x denser you could even breathe it for a limited amount of time, while there's possibly enough oxygen to sustain you, there's far too much carbon dioxide and you will get a CO2 poisoning from it. The thiness al...
by TmEE co.(TM)
Tue Sep 10, 2019 4:43 pm
Forum: Hardware
Topic: Making Light gun for LCD TV
Replies: 42
Views: 26186

Re: Making Light gun for LCD TV

Composhit is always available, even if one uses RGB. In a proper cable the composhit line is used for sync info for example and also acts as fallback when TV isn't supporting RGB via the SCART. It is also trivial to get luminance info out of both composhit and RGB, and sync you always have side by s...
by TmEE co.(TM)
Sun Sep 08, 2019 1:23 am
Forum: Megadrive/Genesis
Topic: Megadrive was always the answer
Replies: 22
Views: 1769

Re: Megadrive was always the answer

Faster CPUs, more RAM and just enhancing VDP and sound is far more useful and much more doable... getting the two sides share single cart is not going to happen more or less though just adding second VDP (and not doing DMA with it) can work out to some extent. It does take a significant FPGA to fit ...
by TmEE co.(TM)
Fri Sep 06, 2019 10:58 pm
Forum: Megadrive/Genesis
Topic: Megadrive was always the answer
Replies: 22
Views: 1769

Re: Megadrive was always the answer

FPGAs are the only solution, and stuff where you can fit substantial amount of things are easily 50€ a chip (but some simpler stuff can be done with the cheap 20€ chips), and you still need various other parts such as DACs, memories, connectors and also plastic, assembly and distribution. What is yo...
by TmEE co.(TM)
Fri Sep 06, 2019 1:50 pm
Forum: Megadrive/Genesis
Topic: Megadrive was always the answer
Replies: 22
Views: 1769

Re: Megadrive was always the answer

I have already explored this sort of stuff, the hardware part is actually easy and not a huge challenge, but it will be incredibly difficult to keep the costs sane even when I used cheapest parts and nobody will pay price of a modern game console for another 32X essentially, which will only ever see...
by TmEE co.(TM)
Mon Sep 02, 2019 11:31 am
Forum: Megadrive/Genesis
Topic: Sega Tech Docs archive
Replies: 26
Views: 4918

Re: Sega Tech Docs archive

Both links are same...
by TmEE co.(TM)
Fri Aug 30, 2019 10:01 am
Forum: Super 32X
Topic: IC mixing video
Replies: 3
Views: 1799

Re: IC mixing video

There is an old RGB encoder chip that's found in some Master System models that has two RGB inputs with means to select between them (I no longer remember the part number of it). I'm not aware of any other all in one things.
by TmEE co.(TM)
Tue Aug 27, 2019 3:32 pm
Forum: Megadrive/Genesis
Topic: Sega Tech Docs archive
Replies: 26
Views: 4918

Re: Sega Tech Docs archive

This is really nice, it is really nice to have everything in one nice place ~
You're free to grab any new things I have gathered up also : http://www.tmeeco.eu/SMD/ http://www.tmeeco.eu/SMS/
by TmEE co.(TM)
Sun Aug 04, 2019 1:07 pm
Forum: Sound
Topic: Looking for latest GEMS
Replies: 29
Views: 12075

Re: Looking for latest GEMS

For now I'm really busy with other things but eventually I could wire up the chips to a counter and record the outputs and give the dump of that, assuming it will be necessary. I don't think the chips do anything more than address decode stuff and their function should be easy to guess. I also tried...