ZX81X2.ROM - and the big bang

Anything Sinclair ZX Basic related; history, development, tips - differences between BASIC on the ZX80 and ZX81
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1024MAK
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Re: ZX81X2.ROM - and the big bang

Post by 1024MAK »

He would most likely used either a 27128 / 27C128 (16K byte) or a 27256 / 27C256 (32K byte) EPROM.

I can't give full connection details at the moment, but will do so later/tomorrow. But basically the highest address line on the EPROM (16K type) or either of the two highest address lines on the EPROM (32K) go to the centre pin of a SPDT switch. One outer switch pin goes to 0V/GND, the other outer switch pin goes to +5V/VCC.

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