MZ 700 - detect PAL/NTSC

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Jo Even
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MZ 700 - detect PAL/NTSC

Post by Jo Even » Tue Oct 01, 2019 6:50 pm

Is there a way to detect video mode (PAL/NTSC) in software? Except for counting cycles between frames of course.

hlide
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Re: MZ 700 - detect PAL/NTSC

Post by hlide » Tue Oct 01, 2019 7:04 pm

Detect which monitor ROM? well, not very standard as well...

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mz-80a
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Re: MZ 700 - detect PAL/NTSC

Post by mz-80a » Wed Oct 02, 2019 11:29 am

Interesting! Presumably just for the MZ-700 / 800 ?
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hlide
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Re: MZ 700 - detect PAL/NTSC

Post by hlide » Wed Oct 02, 2019 1:39 pm

Hardware: get the pin 41 of M60719 (N/P): L = PAL / H = NTSC. But you need to make a circuit to let teh CPU to capture this signal.

Software: 8253.CLK1 = /BLNK. Between two fall-edge /VSYNC count how many /BLNK occurs (reading CNT1 before and after and compute delta for instance). It should give the number of lines which should reflect a PAL or NTSC number of lines.

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