SpritesMind.Net

FWIW, BlastEm nightly builds also have Mode 1 support these days and might run on a slightly less beefy machine. My CD compatibility is currently a fair bit worse at the moment, though I do much better on mcd-verficator. I think Genesis Plus GX also supports Mode 1 boot these days, but I've ...

- Is the problem I see just something that is related to the Exodus emulator? I didn't encounter it yet on my Mega Drive model 2, or with other emulators. But maybe it does happen on other mega drive or genesis models and Exodus is just a better emulator than others?
In general, if something ...

I have already corrected the code (disabling VBL IRQ was unnecessary), but I wonder why it works on emulators (fusion, exodus, kgen) and not on the console.

EDIT...
Eh ... I already know what is wrong, instead of writing $ 8114 under mode set register #2 I wrote $ 8120 ... :(

So you ...

The only real restriction is that setting VDP registers also messes with the configured address/destination for writes/reads/DMA. The other thing to keep in mind is that disabling vertical interrupts this way is that it doesn't clear the interrupt pending state. So let's say you had vertical ...

Yeah, TI_ has been posting results periodically in the BlastEm discord, but I've been slacking on fixing issues

But before I hit the buy it now button on the 16 channel one, I just wanted to check, if this logic analyser can only sample at 16MHz for 16 channels at once, would that be fast enough for analysing the Mega Drive cartridge bus?
In general, you need your sample rate to be at least twice as fast as ...

What is interesting is that if I involve the CE0 signal at all in my CPLD code, the retail reader fails to get any correct data off my cart.
It only works if I only use CAS0. With CE0, the reader says it is an unknown cartridge with no name, 0MB of size and 0KB of SRAM size.
I'm not sure why your ...

I guess MOVEM.W is just such a rare instruction that most games run fine even when its totally broken?

So I think it's not so much that it's a super rare instruction, but that it's not very typical to do movem.w and then depend on the full longword value.

There's that strange text crawl in ...

I don't know how "c00000" addresses palette 0, color 0
So the VDP contains an internal address pointer and a separate register called CD which stores which type of RAM you want to access and whether you want to read or write it. The 32-bit command word you write to the control port sets both of ...

The Mega Everdrive supports 10MB flat carts so it's definitely been tried (and I can confirm DMA does not work in the >8MB region, though I suppose it's possible there's something specific to the MED implementation). Pretty sure this is the first discrete logic implementation though

One little caveat here is that the way the Mega Everdrive handles SRAM with its extended "SSF2" mapper is not the same as the way the standard Sega mapper does. On the MED, one of the banks you can select is mapped to SRAM (except on the v1 which has no dedicated SRAM, though one of the banks is ...

I read about /DTACK (data transfer acknowledge), it needs to be assert for $80 0000 - $9F FFFF.
I need to pull it low when accessing this area.

I planned to assert it when /AS is low and the address lines match $80 0000 - $9F FFFF, meaning A23 high, A22 low and A21 low. Would using a 139 decoder ...

This seems to indicate there are actually 32 registers in CDC chip, not 16 as described in LC591x manual, and that AR register (register index) does not reset to 0x00 when register 0xF is read but when register 0x1F is read, which again contradicts LC591x manual and is kinda unexpected.

Did you ...

Both horizontal and vertical interrupts have an interrupt pending flag. This flag gets set if the necessary condition (hint counter expiring/end of frame) is hit even if the corresponding interrupt is disabled. If the interrupt is enabled when the pending flag is already set, it will fire almost ...

BlastEm is the only emulator to (partially ?) emulate it so be sure to use this emulator which is the most accurate by far when you are testing obscures things like that :)

Yeah, my support is fairly minimal at the moment. I emulate 128KB mode's impact on the FIFO, but I don't support actually ...