Search found 293 matches
- Sat Oct 31, 2015 9:35 pm
- Forum: Megadrive/Genesis
- Topic: M68K Interrupt Processing
- Replies: 7
- Views: 7893
Re: M68K Interrupt Processing
I had a similar problem in a non-Genesis related system. I posted on the Freescale forums a while back and learned that the autovectored interrupts are acknowledged synchronously to the E clock (as a remnant of using VPA for 6800-type synchronous bus cycles), and as the E clock can't be reset to any...
- Fri Oct 30, 2015 7:26 am
- Forum: Hardware
- Topic: Game Toshokan
- Replies: 10
- Views: 12429
Re: Decapping more Genesis chips
Isn't the RAM for the games you download through the modem? Or is there something else weird about how the cart works?Sik wrote:(what does Game Toshokan do, anyway? the only custom hardware in it is 128KB of RAM as far as I know)
- Sun Oct 25, 2015 9:09 pm
- Forum: Hardware
- Topic: Decapping more Genesis chips
- Replies: 17
- Views: 62437
Re: Decapping more Genesis chips
For what matters, register $A11000 (the one that makes the console output a refresh signal on the cartridge slot) only works on early revisions, being a no-op on later versions. Aha, I never knew that and was wondering why my second-revision Megadrive was doing nothing special when using $A11000. :...
- Tue Sep 29, 2015 5:49 am
- Forum: Megadrive/Genesis
- Topic: Charles McDonald's 32X and Sega CD Documents
- Replies: 2
- Views: 3221
Re: Charles McDonald's 32X and Sega CD Documents
I didn't, sorry to say.
- Mon Aug 17, 2015 1:41 am
- Forum: Megadrive/Genesis
- Topic: Using an Atari 2600 paddle controller in a genesis homebrew
- Replies: 3
- Views: 4119
Re: Using an Atari 2600 paddle controller in a genesis homeb
Does that mean a Genesis couldn't make use of the paddle controller no matter how it was programmed? That's right. The Atari systems that used the paddle had dedicated hardware for converting the the two analog inputs on the connector to a digital value for the CPU to read. For that reason it's not...
- Wed Aug 12, 2015 5:23 am
- Forum: Megadrive/Genesis
- Topic: Sprite Isn't Showing Up
- Replies: 35
- Views: 21521
- Wed Aug 12, 2015 12:06 am
- Forum: Megadrive/Genesis
- Topic: Sprite Isn't Showing Up
- Replies: 35
- Views: 21521
- Mon Aug 10, 2015 1:04 am
- Forum: Hardware
- Topic: FPGA version
- Replies: 26
- Views: 65977
- Fri Aug 07, 2015 4:09 pm
- Forum: Hardware
- Topic: FPGA version
- Replies: 26
- Views: 65977
This thread makes perfect sense. Especially when you see Analogue Interactive releasing a $500 - gorgeous - NES. The FAQ mentions that these systems are built up from old consoles using the original CPU and PPU chips that they cannibalized. I'm sure the HDMI video processing and such is nice, but i...
- Thu Aug 06, 2015 4:34 am
- Forum: Hardware
- Topic: FPGA version
- Replies: 26
- Views: 65977
Re: FPGA version
While they all claim their versions aren't finished, i'll like to know if a FPGA (or a SoC) version of Genny is possible ? The SoC versions are just emulation running on an embedded platform, so it can be as good as the emulation they use (or steal :)) A FPGA version that is close to perfect is def...
- Tue Jul 28, 2015 1:14 am
- Forum: Megadrive/Genesis
- Topic: DMA from ROM to CRAM, results are garbage
- Replies: 15
- Views: 12153
Re: DMA from ROM to CRAM, results are garbage
The source data in ROM can't cross a 128K boundary too, so maybe confirm the data is within a 128K block.
E.g. if the palette data starts at $05FFF0, the DMA will wrap to $040000 past $05FFFF instead of continuing from $060000 like you think it should.
E.g. if the palette data starts at $05FFF0, the DMA will wrap to $040000 past $05FFFF instead of continuing from $060000 like you think it should.
- Thu May 07, 2015 5:45 pm
- Forum: Controls
- Topic: Saturn = Genny ?
- Replies: 3
- Views: 8806
Re: Saturn = Genny ?
Yep, they are the same. Other than the connectors being physically different, the Saturn and Genesis controller ports are electrically identical. The polling is more involved for some of the Saturn peripherals, but it's no worse than accessing the Mega Mouse I suppose. With the right adapter you cou...
- Sun Apr 26, 2015 4:03 am
- Forum: Blabla
- Topic: best emulator on android?
- Replies: 7
- Views: 11215
Ah yeah, of course i was using the free version... did not know it was based on Genesis Plus GX, i know it was also using some part of Gens code for the Sega CD emulation. I have the feeling he asked for permission to use parts of Gens Sega CD emulation as a cover for continuing to misuse Genesis P...
- Sat Mar 28, 2015 12:52 am
- Forum: Hardware
- Topic: MOVEM quirk
- Replies: 2
- Views: 7960
That's right, it happened when the source was (An), (An+), ($nnnn).w, etc. I tried all of the ones I could think of.Stef wrote:Interesting, does the extra cycle happen also with (An) indexing ?, i guess so ! That also explains why MOVEM.w Mem-->Reg is 12+4n cycles
when MOVEM.w Reg --> Mem is 8+4n cycles.
- Thu Mar 26, 2015 6:09 pm
- Forum: Hardware
- Topic: MOVEM quirk
- Replies: 2
- Views: 7960
MOVEM quirk
I ran into an interesting problem when debugging software on a 68K SBC. When doing a memory-to-register transfer using MOVEM of any size (word,long) with any EA mode, it will read one extra address past the last legitimate location. This read is word sized even if transferring words or longwords. Fo...