Search found 685 matches
- Tue Mar 29, 2022 9:06 am
- Forum: Off-topic
- Topic: a short self-introduction
- Replies: 4
- Views: 4168
Re: a short self-introduction
Welcome aboard! look for SP-5025. That's the basic which was delivered with the MZ-80 K. They are a lot of variants but that one is the original sold with MZ-80 K.
- Sun Mar 06, 2022 10:04 pm
- Forum: Assembly
- Topic: HBLANK (MZ-80A)
- Replies: 25
- Views: 13340
Re: HBLANK (MZ-80A)
Let us see later, my actual situation is not propice for doing so.
- Fri Mar 04, 2022 11:02 pm
- Forum: Assembly
- Topic: HBLANK (MZ-80A)
- Replies: 25
- Views: 13340
Re: HBLANK (MZ-80A)
And yes, on MZ-80 K schematics, Z80 /WAIT is directly connected to 5V through a pullup. At least, it is clear. For MZ-80 A, just a label /WAIT. It cannot be floating so it lacks at least a circuit mixing /EXWAIT to connect Z80 /WAIT.
- Fri Mar 04, 2022 10:38 pm
- Forum: Assembly
- Topic: HBLANK (MZ-80A)
- Replies: 25
- Views: 13340
Re: HBLANK (MZ-80A)
Usually it is up to the peripheral card to set the /EXWAIT pin, not the GAL. MZ-700 LSI outputs /WAIT but not for $F000-$FFFF so I don't think it is the case for MZ-80A too. The /EXWAIT and /WAIT should have a circuit so it can feed the Z80. But the actual schematics show nothing about the circuit a...
- Fri Mar 04, 2022 8:10 am
- Forum: Assembly
- Topic: HBLANK (MZ-80A)
- Replies: 25
- Views: 13340
Re: HBLANK (MZ-80A)
And how does MZ-80 A handle the VRAM conflict?
- Fri Mar 04, 2022 8:09 am
- Forum: Assembly
- Topic: HBLANK (MZ-80A)
- Replies: 25
- Views: 13340
Re: HBLANK (MZ-80A)
So you means when GAL decodes $F000-$F3FF, it generates one cycle /EXWAIT? That's so weird.
- Fri Mar 04, 2022 8:07 am
- Forum: Assembly
- Topic: HBLANK (MZ-80A)
- Replies: 25
- Views: 13340
Re: HBLANK (MZ-80A)
20µs is indeed very short. I'm not sure why the GAL is connected to /EXWAIT as an input or as an output especially for $F000-$F3FF. It remains a mystery for me.
- Thu Mar 03, 2022 10:56 pm
- Forum: Assembly
- Topic: HBLANK (MZ-80A)
- Replies: 25
- Views: 13340
Re: HBLANK (MZ-80A)
Yes but sampling should be done upon $E008.D7 (BLNK pulse) and not upon $E008.D0 (TEMPO pulse) as you seem to suggest to Ben.
- Thu Mar 03, 2022 3:59 pm
- Forum: Assembly
- Topic: HBLANK (MZ-80A)
- Replies: 25
- Views: 13340
Re: HBLANK (MZ-80A)
And I cannot find the link between /WAIT (connected to Z80) and /EXWAIT (connected to GAL) in the MZ-80 A schematics. /WAIT is just connected to Z80 with no pull in sight and I cannot spot /WAIT somewhere else. I suspect the schematics missing that part.
- Thu Mar 03, 2022 3:45 pm
- Forum: Assembly
- Topic: HBLANK (MZ-80A)
- Replies: 25
- Views: 13340
Re: HBLANK (MZ-80A)
MZ-80 K:
MZ-700: