Questions tagged [zx80]

The Sinclair ZX80 was a low cost home computer introduced in 1980.

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Did the ZX80 RAM pack pass the expansion bus through?

The ZX80 only came with 1K of RAM, which had to be shared between program and screen memory, so many customers bought the Sinclair 16K RAM pack, which plugged into the expansion bus (the edge ...
29
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3answers
5k views

Why did the ZX80 CPU run at only 3.25 MHz?

The Sinclair ZX80 used a Z80A running at 3.25 MHz. But this chip was rated for 4 MHz. Why was it run below rated speed? Apparently the master clock in the machine ran at 6.5 MHz, so the CPU clock ran ...
6
votes
1answer
477 views

How did the ZX80 RAM pack use DRAM?

The Sinclair ZX80 was the most popular personal computer in Britain at the beginning of the 1980s, due to its low price which was enabled by extreme minimalism; it consisted of not much more than a ...
7
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1answer
461 views

Why is ZX80 much faster than Spectrum on Rugg/Feldman benchmarks?

If you look at the results of the Rugg/Feldman benchmarks, shown in this Wiki entry, you'll see that Sinclair ZX80 is much faster than Sinclair Spectrum on all tests despite the fact that both ...
19
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2answers
3k views

How did the ZX80 store both a useful program and screen memory?

I have a vague recollection from my earliest days that the ZX80 only shipped with 1K of RAM. If this RAM was used to store both the program and the contents of the 32x24 screen, wouldn't that mean ...
12
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2answers
1k views

Why does the ZX80 not produce a steady display signal?

As Tommy pointed out in my question about BASIC tokens on the ZX Spectrum, the ZX80 is a computer which does not produce a signal which is displayed steadily on the TV. It looks to me as if the CRT is ...
10
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3answers
432 views

ZX80 BASIC checking free memory

Did ZX80 BASIC have a way to check how much memory you were using and how much was left? Or otherwise: if you were writing a program on a machine with the RAM expansion, was there a way to tell ...