New RC2014 boards: RS232 and 8052

April 24, 2018

I got a bumper box of PCB’s in the post today, just in time for Maker Faire UK 2018 this weekend (29th/30t April 2018).

Inside the box were some new RC2014 boards. The first two new PCB’s were my respins of a Z80 SIO/2 serial board and a Raspberry Pi Zero terminal board, as well as two brand new designs.

The first brand new board was a RC2014 RS232 breakout board allowing TxD1/RxD1 and/or TxD2/RxD2 serial signals from the RC2014 bus to be driven at RS232 levels.

The second brand new PCB was a new 8052 CPU board. This is a bit of an experimenters board as the 8052 bus architecture doesn’t directly map onto the Z80 bus architecture. When using the 8052 CPU some of the Z80 control bus signals (!M1, !MREQ, !IORQ etc.) will need pulling low via jumpers when attempting to make use of other cards. So why all the fuss. Well, the 8052 CPU does have the excellent the 8052-BASIC available which does make it a fun and a powerful (in 1980/1990 micro terms 🙂 ) system.

Advertisements

RC2014 Prototype Board

February 23, 2018

The Prototype card is one of the very first cards I designed for the RC2014 system.

It’s larger than a normal RC2014 card but that is intentional so you have as much prototyping area as possible for building a circuit.

It features both the classic single row pin-header for the original RC2014 pin-out and also a double row pin-header for the newer enhanced RC2014 bus pin-out.

 

 

You can find them on my Tindie store


RC2014 Z80 System with enhanced bus

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:


Z80 Card

Memory Card

 

ACIA UART Card

 


Big Box of PCB’s

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.


Retro Computing with the RC2014 Bus

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:

https://rc2014.co.uk/
https://github.com/semachthemonkey/RC2014
https://github.com/RC2014Z80
http://www.sowen.com/tag/retro-challenge/
https://github.com/RFC2795

http://www.smbaker.com/
https://github.com/sbelectronics/rc2014

http://ancientcomputing.blogspot.co.uk/
https://github.com/ancientcomputing/rc2014

https://github.com/electrified/rc2014-ym2149

https://github.com/mattybigback/RC2014

https://github.com/anachrocomputer/RC2014tester
https://github.com/mooped/rc2014_bank_switcher
https://github.com/mooped/rc2014_tools
https://github.com/trcwm/rocket2014

Other Platforms
http://www.ndr-nkc.de/compo/index.htm //very similar system from 1980’s
http://hschuetz.selfhost.eu/ndr/doku/buch/index.html
https://www.retrobrewcomputers.org/forum/index.php?t=msg&goto=2148&
https://www.funkenzupfer.de/CMSimple_4-7-2/?NDR-Klein-Computer