January 28, 2018
I’ve been busy with my big box of PCBs and I here’s my first Z80 system design and build. It comprises of the following:
– Z80 CPU card
– 8K ROM & 8K SRAM card
– 68B50 ACIA card
– 5-slot enhanced+ backplane
It’s pretty much a standard Z80 layout but I’ve expanded the bus to the latest Enhanced Bus definition for all the cards. The 5-slot backplane uses double row (2×39) female pin headers to include the RC2014 enhanced bus and in addition I’ve added an extra set of address lines (A16 to A23) for the possibility of using 16-bit CPU’s (8086/68000) and memory options (upto 1MB) in the future.
Here’s some pics of the various cards:
ACIA UART Card
December 27, 2017
Christmas came slightly early this year when a big box of PCB’s arrived.
Inside the box where a bunch of PCB’s for making guitar effects boards.
As well as a bunch of PCB’s for my take on a RC2014 Z80 based retro computing system.
More pics to follow when I’ve built them up.
November 29, 2017
I have very fond memories of using and building 8-bit computers during the 1980’s, so I’ve been following Spencer Owen’s RC2014 modular 8-bit computer project with some interest. For those interest the RC2104 is a simple but very modular 8-bit microcomputer based around the Z80 microprocessor.
In its most basic form it uses a number of single row 40-pin headers (or sometimes a 39-pin header) to make a computer backplane and which takes various “computer” and add-on cards to build a system. The add-on cards currently have a choice from various Z80 CPU cards, a 6502 CPU, various sizes of RAM and ROM memory cards, serial I/O and digital I/O cards.
I was fortunate to meet Spencer at Maker Faire UK back in April 2017 and chat with him first hand about the RC2014 project and he was very open and enthusiastic about sharing all aspects of his project. So much so, a small community of fellow builders has popped up and added to the project with their own add-on cards.
I’ve put together a short list of RX2014 related web-sites:
http://www.ndr-nkc.de/compo/index.htm //very similar system from 1980’s
October 18, 2017
A few weeks back we were in eDay6 at Gateshead Central Library. This is the 6th year we’ve been at this great event.
For those who don’t know what eDay is: eDay is a local digital skills day where various digital technologies are demonstrated to an enquiring general public. A sort-of geeky show and tell where local groups and individuals meet at Gateshead Central Library and show off their projects or what interests them.
Maker Space has played a mayor role since it first started 6-years ago with demonstrations on 3D Printers, CNC machines, Arduino’s and Raspberry Pi. Other were there with Quad Copter racing, Ham Radio and retro.
September 27, 2017
Way back in 2015 I started making guitar effect pedals for my own education and amusement. I built a couple of classic pedals in the familiar 1590B enclosure where I hardwired input / output jacks and foot switches to the effects circuitry. From this experience one of the things I went on to design was a breakout board for the 3PDT foot switch. This is it here:
August 31, 2017
Members of ESP32.com forum will recognise Neil Kolban as one of its more prolific commentator and posters. As well as his great contributions to the forum he has also put together a great book on the ESP32 hardware and software. He constantly reviews and keeps it up to date so its a bastion of ESP32 knowledge. You can find a copy here:
July 27, 2017
In a previous post on setting MIDI baud-rates on the RPi I used a slight of hand (i.e. init_uart_clock etc.) to trick the RPi in setting the UART to a 31250 baud needed for MIDI. While browsing the Raspberry Pi forum I spotted this nugget of information from PhilE:
in config.txt add:
This combination does three things:
1) Enables the UART. It isn’t strictly necessary when combined with pi3-miniuart-bt
2) Reassigns the weaker UART (ttyS0) for Bluetooth and frees ttyAMA0 for our MIDI interface
3) Using an DT overlay to achieve the same UART clock settings as our init_uart_clock etc. trick
It makes things a lot simpler 🙂