Search found 2615 matches

by Chilly Willy
Thu Nov 29, 2018 7:33 pm
Forum: Megadrive/Genesis
Topic: Looping access from 68K and Z80
Replies: 25
Views: 980

Re: Looping access from 68K and Z80

Thanks for the link. Their search really sucks. I couldn't get a single hit from any form of the part number.
by Chilly Willy
Tue Nov 27, 2018 1:34 pm
Forum: Megadrive/Genesis
Topic: Looping access from 68K and Z80
Replies: 25
Views: 980

Re: Looping access from 68K and Z80

How long ago was that? Can't seem to find any at Quest at all.
by Chilly Willy
Tue Nov 20, 2018 3:05 pm
Forum: SGDK
Topic: XGM Driver issue
Replies: 21
Views: 546

Re: XGM Driver issue

It was easier on old compilers because said compilers didn't try things like reordering execution of code trying to get that extra 1% speed up... which is hilarious considering modern gcc for 68000 tends to be SLOWER than those old compilers.
:lol:
by Chilly Willy
Tue Nov 20, 2018 3:01 pm
Forum: Megadrive/Genesis
Topic: Looping access from 68K and Z80
Replies: 25
Views: 980

Re: Looping access from 68K and Z80

Who do you buy you Genesis chips from? I'd love to get a few for my own purposes.
by Chilly Willy
Tue Nov 20, 2018 2:50 am
Forum: SGDK
Topic: XGM Driver issue
Replies: 21
Views: 546

Re: XGM Driver issue

Any code that deals with hardware must use volatile pointers AND have memory barriers protecting it or you'll have issues depending on the optimization level. I ran into that early on with the 32X. In general, memory barriers aren't discussed on the net except for x86. So it can be difficult finding...
by Chilly Willy
Mon Nov 19, 2018 2:26 pm
Forum: SGDK
Topic: XGM Driver issue
Replies: 21
Views: 546

Re: XGM Driver issue

Code: Select all

while(!Z80_isDriverReady())
	while(Z80_isBusTaken());
You DO realize that Z80_isBusTaken() merely checks if the 68k has halted the Z80? That "while(Z80_isBusTaken());" either does nothing, or it hangs forever, depending on if the Z80 has been halted.
by Chilly Willy
Sun Nov 18, 2018 1:51 pm
Forum: Megadrive/Genesis
Topic: Looping access from 68K and Z80
Replies: 25
Views: 980

Re: Looping access from 68K and Z80

Well, it does sound like A0xxxx does just address the z80 decoder then. Mostly. As said earlier, the z80 rom bank is apparently not part of that. I wonder if that's because it's handled separately on the z80 side, or if one less address line from the 68000 feeds the decoder. That would prevent recur...
by Chilly Willy
Sat Nov 17, 2018 5:01 pm
Forum: Hardware
Topic: Controllers and wrong I/O pin directions
Replies: 9
Views: 624

Re: Controllers and wrong I/O pin directions

I mean, most games only support controllers and misbehave the moment you connect anything else, so not checking for anything not explicitly supported isn't unusual. Yeah, loads of games that hang if you have a mouse plugged in, for example. I tend to leave my mouse unplugged unless I plan to use it...
by Chilly Willy
Sat Nov 17, 2018 4:31 pm
Forum: Megadrive/Genesis
Topic: Looping access from 68K and Z80
Replies: 25
Views: 980

Re: Looping access from 68K and Z80

You can find some answers in Charles MacDonald's hardware notes: https://github.com/Emu-Docs/Emu-Docs/blob/master/Genesis/gen-hw.txt 3. Addresses A08000-A0FFFFh mirror A00000-A07FFFh, so the 68000 cannot access it's own banked memory. All addresses are valid except for the VDP which is at A07F00-A0...
by Chilly Willy
Fri Nov 16, 2018 2:42 pm
Forum: Hardware
Topic: Controllers and wrong I/O pin directions
Replies: 9
Views: 624

Re: Controllers and wrong I/O pin directions

They only unique IDs I've found are #define PORT_TYPE_MENACER 0x00 #define PORT_TYPE_JUSTIFIER 0x01 #define PORT_TYPE_MOUSE 0x03 #define PORT_TYPE_TEAMPLAYER 0x07 #define PORT_TYPE_PAD 0x0D #define PORT_TYPE_UNKNOWN 0x0F The keyboard is missing from that since there's no keyboard support in SGDK as ...
by Chilly Willy
Fri Nov 16, 2018 2:27 pm
Forum: Megadrive/Genesis
Topic: Looping access from 68K and Z80
Replies: 25
Views: 980

Re: Looping access from 68K and Z80

Having a consistent mapping is not the same thing as using the same mapping circuitry. Since the only thing the 68000 can access in "z80 space" is the ram and FM, I'd be more inclined to believe it's not using the same mapping. They simply made the ram and FM map in a similar place to make it easier...
by Chilly Willy
Thu Nov 15, 2018 1:03 am
Forum: Hardware
Topic: Controllers and wrong I/O pin directions
Replies: 9
Views: 624

Re: Controllers and wrong I/O pin directions

You should always try to ID the peripherals before changing lines. The controllers that need TR reversed: the mouse, the keyboard (rare), and the multitap. All can be IDed before changing the direction of TR. SGDK does so. You can force support for controllers, but that's all on the programmer at th...
by Chilly Willy
Thu Nov 15, 2018 12:58 am
Forum: Megadrive/Genesis
Topic: Looping access from 68K and Z80
Replies: 25
Views: 980

Re: Looping access from 68K and Z80

The Z80 map doesn't apply to the 68000 side at all. The 68000 has it's own map, and doesn't use the Z80 map.
by Chilly Willy
Sun Nov 11, 2018 1:27 pm
Forum: Blabla
Topic: aliexpress genesis with same logo as spritesmind
Replies: 5
Views: 548

Re: aliexpress genesis with same logo as spritesmind

Very weird... the controllers have that on them, too. It's clearly the SpritesMind logo.

I put three of the pic here to make it easier to view: https://imgur.com/a/YBeNKqQ

Note the box - MindKids?
by Chilly Willy
Fri Nov 09, 2018 11:57 pm
Forum: SGDK
Topic: An error check in the 3 line handshake
Replies: 12
Views: 622

Re: An error check in the 3 line handshake

Yeah, didn't think about hot plugging... they'd have to try to set the support any time they looked for hot plugged controllers.

So, early out it is! Well, unless you make an official interface for handling hot plugging. Maybe a callback the user registers for when controllers change.