Search found 260 matches

by hlide
Wed Sep 18, 2019 12:12 pm
Forum: Other
Topic: Detecting VBL on 800 in 700-mode
Replies: 21
Views: 95

Re: Detecting VBL on 800 in 700-mode

Did you try with EmuZ-800?
by hlide
Wed Sep 18, 2019 12:10 pm
Forum: Other
Topic: Detecting VBL on 800 in 700-mode
Replies: 21
Views: 95

Re: Detecting VBL on 800 in 700-mode

Jo Even wrote:
Mon Sep 16, 2019 5:49 am
It doesn't work on a real 800 either.
Is that so? did you test it yourself and put the rear switch in the exact position for MZ700 mode?
by hlide
Tue Sep 17, 2019 5:39 pm
Forum: Other
Topic: Detecting VBL on 800 in 700-mode
Replies: 21
Views: 95

Re: Detecting VBL on 800 in 700-mode

Ok, it seems PIO of MZ-800 can issue an interrupt for /VBLN, I suppose when you execute the PIO interrupt, you must check PA5 to see if /VBLN is the interrupter. While in MZ700, I guess there is no such interrupt so you should rely on polling PC7 of 8255. But for an unknown reason it doesn't work...
by hlide
Mon Sep 16, 2019 12:26 pm
Forum: Other
Topic: Detecting VBL on 800 in 700-mode
Replies: 21
Views: 95

Re: Detecting VBL on 800 in 700-mode

sm800_1.png
sm800_2.png
sm800_4.png
sm800_3.png
sm800_5.png
- PIO.A5, is input, reading 1 when its source is not active.
- 8255.PC7, is input, reading 1 when its source its source is not active.
Could you post you snippet of source which doesn't work with MZ800 (I suppose you're in MZ700 mode)?
by hlide
Mon Sep 16, 2019 11:46 am
Forum: Other
Topic: Detecting VBL on 800 in 700-mode
Replies: 21
Views: 95

Re: Detecting VBL on 800 in 700-mode

Remember I told you /VBLN is connected to two pins: 8255 and PIO. I'm not sure why PIO needs it and in which direction it is (is that an input or output?).
by hlide
Sun Sep 15, 2019 5:11 pm
Forum: Emulation
Topic: STMZ800
Replies: 2
Views: 17

Re: STMZ800

It is not complete. You'll need to finish it.
by hlide
Sun Sep 15, 2019 8:43 am
Forum: Other
Topic: Detecting VBL on 800 in 700-mode
Replies: 21
Views: 95

Re: Detecting VBL on 800 in 700-mode

So basically, either your condition jump nor its inverse are taken to loop? The way you say it implies a bad instruction emulation.
by hlide
Sat Sep 14, 2019 9:43 pm
Forum: Other
Topic: Detecting VBL on 800 in 700-mode
Replies: 21
Views: 95

Re: Detecting VBL on 800 in 700-mode

Huh. VBLN means /VBL which means VBL is active when it is 0, so I supposed you were getting always 1 and never 0. Am I wrong?
by hlide
Sat Sep 14, 2019 3:25 pm
Forum: Other
Topic: Detecting VBL on 800 in 700-mode
Replies: 21
Views: 95

Re: Detecting VBL on 800 in 700-mode

Would it be an issue that you may miss the /VBL even between two polling because the emulator is not running Z80 instructions with the exact timing!? you know, some emulator may run a batch of instructions then pause then resume so the average of cycles is close to 3.5 MHz?
by hlide
Fri Sep 13, 2019 9:58 pm
Forum: Other
Topic: Detecting VBL on 800 in 700-mode
Replies: 21
Views: 95

Re: Detecting VBL on 800 in 700-mode

I have the same feeling unless the macro is really active when it gives 0. But that inversion may explain the strange behavior but that would be weird that such a bug exists.