Search found 20 matches

by Jpg3D
Sun Oct 29, 2017 6:45 pm
Forum: Video Display Processor
Topic: 16 colors 1 hscan
Replies: 8
Views: 10765

Re: 16 colors 1 hscan

If you are developing a game, what are you going to do: use the 100% of the cpu just to wait for the correct scanline? A smart solution, proposed by other members, is to use the h exception of the previous line and then check for the wanted line on the counter. Dont worry, this is just a timing tes...
by Jpg3D
Sun Oct 29, 2017 4:07 pm
Forum: Video Display Processor
Topic: 16 colors 1 hscan
Replies: 8
Views: 10765

Re: 16 colors 1 hscan

after polling the hv counter i achieved to dma 16 colors on only 1 hscan removing the garbage. it's basically the same code. Im trying to do some improvements because the synchronization does not work if the console is overclocked. You can test the rom here. I would apreciate if someone test this ro...
by Jpg3D
Sun Oct 29, 2017 1:23 pm
Forum: Video Display Processor
Topic: 16 colors 1 hscan
Replies: 8
Views: 10765

16 colors 1 hscan

Hi again spritesmind users. After watching this video and seeing this can be achieved, https://www.youtube.com/watch?v=nt-AxAqlrOo i was trying to replicate the scrolling floor effect. So i decided to debug that level in regen emulator. After a few minutes i discovered that the game does not use int...
by Jpg3D
Mon Jul 17, 2017 4:41 pm
Forum: Megadrive/Genesis
Topic: Console freezes when reset
Replies: 8
Views: 6124

Re: Console freezes when reset

Thank you for your answers!
by Jpg3D
Sun Jul 16, 2017 6:39 pm
Forum: Megadrive/Genesis
Topic: Console freezes when reset
Replies: 8
Views: 6124

Re: Console freezes when reset

This is talked about in the Software Guidelines, section 3. The first thing is to always wait on the BUSY bit for the DMA after a reset. Even that isn't guaranteed to solve the issue if the reset occurred at a specific point in the bus grant handshake while starting a DMA. To solve that case, you s...
by Jpg3D
Sun Jul 16, 2017 7:54 am
Forum: Megadrive/Genesis
Topic: Console freezes when reset
Replies: 8
Views: 6124

Re: Console freezes when reset

Also something that is at the very least possible, is trying to wait for Z80 to stop when its not in a correct state, I remember getting this issue frequently when ROMs do not properly reset/initialize Actually i do not initialize z80 in any of my roms. And only this one has this effect. A random i...
by Jpg3D
Sat Jul 15, 2017 5:56 pm
Forum: Megadrive/Genesis
Topic: Console freezes when reset
Replies: 8
Views: 6124

Console freezes when reset

Hi again to everyone. I know i'm not a really active member of this community. But i would like to converse about a bug that i found at one of my roms. This bug just consists that the console freezes after pressing the reset button several times very fast. Then sometimes the console completely freez...
by Jpg3D
Thu Apr 27, 2017 6:28 pm
Forum: Sound
Topic: z80 BankSwitch reset/initialize
Replies: 2
Views: 6997

Re: z80 BankSwitch reset/initialize

Really thank you for your fast and clear answer. Now i fully understand how to use that register.
by Jpg3D
Thu Apr 27, 2017 6:03 pm
Forum: Sound
Topic: z80 BankSwitch reset/initialize
Replies: 2
Views: 6997

z80 BankSwitch reset/initialize

Hi spritesmind users. i have searched for some documentation about z80 bank register. Because i'm implementing my own z80 sound driver. After reading this helpfull document https://emu-docs.org/Genesis/gen-hw.txt i found that i only have to write one by one the 9 high bits of my window direction to ...
by Jpg3D
Thu Apr 27, 2017 5:51 pm
Forum: Demos
Topic: OVERDRIVE II
Replies: 29
Views: 42768

Re: OVERDRIVE II

315-5433 in the IO+bus management chip. VDP is the other chip (315-5313 / 5313A / 5313A-01)
You'r right. Post Fixed.
by Jpg3D
Thu Apr 27, 2017 3:43 pm
Forum: Demos
Topic: OVERDRIVE II
Replies: 29
Views: 42768

Re: OVERDRIVE II

https://s4.postimg.org/7m6juaggt/photo_2017-04-27_17-37-30.jpg This is the only error i get on my megadrive. Sometimes the video looses syncs so my screen turns off and i cant see any. Sometimes the demo looks fine. But that robots seems to be corrupt on every test Tested on PAL-B(VE) nº 1061-07 se...
by Jpg3D
Fri Nov 11, 2016 6:26 pm
Forum: Video Display Processor
Topic: DMA failure on different consoles.
Replies: 12
Views: 13585

Re: DMA failure on different consoles.

Thank you all for you help. It really helped me to think back to my first code and fix it. Finally the error was fixed after rewritten A LOT of ugly n00bish code. Probably there were something wrong at my very beginning lines because i had not really good idea of how to program this machine. I fixed...
by Jpg3D
Wed Nov 02, 2016 6:51 pm
Forum: Video Display Processor
Topic: DMA failure on different consoles.
Replies: 12
Views: 13585

Re: DMA failure on different consoles.

I aligned the size to exactly 131.072 bytes (128kbs), blocked interrupts, and rewritted the DMA function so now it's much faster. It's almost a copy from the DMA function that you can find at this website. http://www.hacking-cult.org/?r/18/25 Unfortunately the problem persists. 100% the same behavio...
by Jpg3D
Tue Nov 01, 2016 12:33 pm
Forum: Video Display Processor
Topic: DMA failure on different consoles.
Replies: 12
Views: 13585

Re: DMA failure on different consoles.

Here's the rom https://ufile.io/56a7 I'm pretty sure that is my fault. Probably i'm missing something on my DMA function that causes this failure on different cartidges, because other homebrew works fine on myfriends MegaDrive. Also i tested it on another system. MegaDrive 2 -> MK-1631-50 <-- Works ...
by Jpg3D
Mon Oct 31, 2016 10:34 pm
Forum: Video Display Processor
Topic: DMA failure on different consoles.
Replies: 12
Views: 13585

Re: DMA failure on different consoles.

Mine is :Megadrive 1 PAL-B(VE) 1601-07 <-- Works fine

Friend's :Megadrive 1 PAL-G 1601-18 <-- Glitchy DMA