Sinclair ZX80 / ZX81 / Z88 Forums

Are you going to use Z80 I/O addressing or are you going to use memory mapped addressing (so that PEEK and POKE can be used)? One of the annoying things about computers and hex is that different systems use different symbols to represent hex :evil: When I first saw things like 0x56 I was confused :?...

Interesting :D I'm not that surprised that a ZX81 running in FAST mode just beats a 48K ZX Spectrum. The BASIC in the Spectrum is a development and extension of the ZX81 BASIC and on a real machine the first 16k of RAM on the Spectrum is affected by the ULA "pausing" the Z80 MPU so that the display ...

Can you say $77 another way? Is there a decimal equivalent? In my world there is a binary address. I set my decoder to enable a chip at a certain address in binary and then a write signal pops out the data that a Poke made. I think there is another GAP in my understanding! 77 hex = 119 dec = 011101...

I repaired one of my ZX81's several years ago, and it is still working perfectly, despite having been taken apart many times. The keyboard had stopped working due to a cracked connector cable. Here is how I repaired it... http://zx80.netai.net/zx81/ZX81KBRepair.htm Regards. Grant. :idea: Now where ...

Of the eBay bought 8 bit machines (not just ZX81's) that I have obtained I have noticed the following as common problems: Keyboard problems - membrane broken or non-functional keys :( , Tarnished connectors (e.g. expansion edge connector) - cleaning normally fixes this :D , Intermittent faults with ...

One thing I learned about computers way back when, is to always have at least one back-up copy... Of course despite knowing this, I still sometimes end up losing items that are a work in progress :cry: (a lot of the time as I am thinking, I'll just make this change then save a copy, then crash :o :s...

PokeMon wrote:Because I can produce in a smaller series I can offer a 3-package.
Maybe I can offer a 5-package as well for about 16 GBP.
But to do I want to collect some orders first.

One pack of five please. Please consider this a firm order.
Mark

Now I ordered only Prototype version with 5 pieces, resulting price will be GBP 7,00 plus GBP 2,00 postage for an envelope. FIFO order service - first in, first out. Should be delivered this month as promised. Now I found a producer in China for smaller series and I could do a smaller series which ...

Selling like hotcakes...
Three ZXpands sold today
Mark

Great pictures Andy
It looks so much better in its home environment next to a Z80 on a Zeddy PCB
Mark