gerard – Geronimo/370

Retro Z80 computer (9) – BLINKENLIGHTS

Posted on2022-01-212022-01-21Leave a comment

A small project today. I added ‘BLINKENLIGHTS’ to my Z80. This term stems from an old sign that used to hang in computer rooms: ACHTUNG!ALLES TURISTEN UND NONTEKNISCHEN LOOKENSPEEPERS!DAS KOMPUTERMASCHINE IST NICHT FÜR DER GEFINGERPOKEN UND MITTENGRABEN! ODERWISE IST EASY TO SCHNAPPEN DER SPRINGENWERK, BLOWENFUSEN UND POPPENCORKEN MIT SPITZENSPARKEN.IST NICHT… Read the rest

Retro Z80 computer (8) – IDE disk

Posted on2022-01-162022-01-19Leave a comment

Where I originally thought that I could connect a floppy to my IDE card (silly me) I seem to have forgotten that IDE is a Hard Disk connection… Oh well, my brother still had an old Hard Disk laying around that he was prepared to part with. Got it today… Read the rest

Origin of radio numeric codes

Posted on2021-12-272021-12-27

Searching for the origin of the ‘73’ code at the end of a message, meaning something like ‘kind regards’, I found the following. Glen Zook, K9STH, posted this to the Heathkit mailing list: Many amateurs already know that “73” is from what is known as the “Phillips Code”, a series… Read the rest

Christmas in the shack

Posted on2021-12-272021-12-27

Do you guys also get the Christmas feeling and make it visible in your shack / workshop? What do you think, is an image like this recognizable? I do… Xmas shack… Read the rest

Retro Z80 computer (7) – Almost complete

Posted on2021-12-212021-12-22

Here’s a picture of the progress so far. It now also includes a RTC (Real Time Clock) module. What you might also notice is the flat cable I attached between the serial card and the serial to USB connector. That connector, as you can see in previous posts, was attached… Read the rest

Retro Z80 computer (6) – It works!

Posted on2021-12-16

I am one happy maker, I got my Z80 computer working right after building. All went well! The first lines of output are the boot screen: CP/M And of course I wanted to see CP/M running: Z80 Basic And after that, on to Z80 Basic version4.7b:… Read the rest

Retro Z80 computer (5) – Dual Clock Module

Posted on2021-12-162021-12-16

Without an internal clock nothing happens inside a computer. It’s the clock that makes the computer ‘tick’, chew away instructions that is. Last I assembled this module; it contains two clocks. Both clock signals are being put on the bus on the Backplane board. It’s starting to look like something…… Read the rest

Retro Z80 computer (4) – Dual Serial Module

Posted on2021-12-15

And another one bites the dust… The Dual Serial SIO/2 module has been assembled and soldered. With this one I had to search for the value of the resistors, because the info was not in the documentation. Eventually I ended up looking at the pictures of an assembled one online… Read the rest

Retro Z80 computer (3) – Memory module

Posted on2021-12-152021-12-15

And the memory module for my Z80 computer is finished. It contains 512K of ROM and 512K of RAM memory.… Read the rest

Retro Z80 computer (2) – backplane and CPU board

Posted on2021-12-152021-12-15

Yesterday evening I assembled and soldered the backplane board and the CPU board. Around 600 solder joints…… Read the rest

Retro Z80 computer (1) – plans

Posted on2021-12-112021-12-15

This holiday season I’m going retro, and build my own Z80 computer from a kit. The kit offers all the separate parts and one has to assemble the whole thing… All the parts Modular design The design of this computer is totally modular. Because it has been thought out very… Read the rest

Resonance measurements / filters

Posted on2021-12-052021-12-05

Yesterday I started with Capacitors / capacity and coils / inductance. Today I did some extensive measuring, first on a C and L in a series tuned circuit, then on a parallel tuned circuit. See schematics here below: For these measurements I used the same setup as yesterday. But this… Read the rest

Resonance frequencies

Posted on2021-12-042021-12-041 Comment

In the HAM course I am following to become a licensed radio amateur, the topic of resonance frequencies came along. To wrap my head around it I did some experimenting. You can find the result below. I have an assortment of capacitors and coils that I can use for these… Read the rest

HAM-gadget (6) – adjustment & enclosure

Posted on2021-11-132021-11-13

In this version I built in the possibility to adjust the summer and wintertime offset from UTC. It’s a very crude offset, I just add or subtract the offset from the UTC hour. Have to think of a better way to do this… Enclosure I built in the gadget in… Read the rest

HAM-gadget (5) – menu structure

Posted on2021-11-072021-11-08

This weekend I built in a menu structure into the HAM-gadget. Also I created a possibility to store and retrieve settings to the ATMEGA328P’s EEPROM, so they are saved for the next time you switch on the device. For now, you have to retrieve them manually, but that’s quicker then… Read the rest