Re: joystick ports

From: Harvey Muzina <>
Date: Sun, 8 Sep 2013 19:52:46 -0700 (PDT)
Message-ID: <>
>> BTW, speaking of the keyboard scan schema of the early  "TED" series,
>> IMHO it's interesting that both the Sinclair ZX80 and  ZX81, and AFAIR
>> even the Spectrum did make it into production with this  "address lines
>> directly used in the keyboard scan process" method |-)
> Yes, but they used the address lines in the ZX, not, as in
> the early 264 models, the data lines. This way the row
> scanned was determined by the address you used to poll the
> single ULA register of the spectrum. Not a bad idea, but it
> meant that you had the keyboard matrix hooked up to the
> address lines. I doubt you would be able to pass FCC
> certification nowadays with a design like this.

The ZX Spectrum versus modern legislation:

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Received on 2013-09-09 03:01:24

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