September 30, 2020
Following on from the Feather prototyping board I showed last time, I’ve finished a few more Feather module designs.
In the picture above, on the right, we have a Raspberry Pi adapter that allows two Feather modules to be used with the RPi. The RPi’s UART, I2C and SPI are available to be used with the Feather modules. You can mixed things around if you want and have a Feather controller and Feather I/O module setup to offload real-time I/O from the RPi or just have two Feather I/O modules to expand the RPis I/O capability.
Next to the RPi adapter, with have an analogue input module using the popular 8-channel MCP3008 ADC (SPI) chip.
Next to that, we have a couple of 16-channel digital port expanders, based on the MCP23017 (I2C) and MCP23S17 (SPI) chips respectively.
As always, I’ll put them up to my Tindie shop
August 30, 2020
I’ve been a long time fan of the Arduino Nano and before those the Arduino Mini boards. I really like the compact Nano footprint and prefer it to the standard Arduino Due style. When I ran of computing processing power I would swap the Nano’s for the STM32 blue pill boards. So I thought I had a good choice of modules to choose from. But this has changed recently and another module footprint has entered my projects orbit.
The Adafruit Feather modules have been around for a few years and a recent project requirement saw me using their nRF52840 Express module for a Bluetooth Low Energy (BLE) based design. I liked what I saw but couldn’t find a decent prototyping solution, so I designed this prototyping / breadboard to help with getting my Feather module projects started.
The FeatherWing prototyping / breadboard has headers for a Feather module, as well as space for a 400-hole breadboard. Additionally it has PCB positions for 3x tactile switches, 3x LED’s and a FTDI style serial pin-header. Finally, all the Feather module signals are broken out to a double row header located next to the breadboard.
As always, I’ll put them up to my Tindie shop
February 26, 2020
Last year Parallax released their latest multicore processor, the Propeller2 or P2X8C4M64P to give it, its full name. It’s been a very long time coming and after a few setbacks it is finally here. It’s specs are very good, featuring 8x 32-bit cores (or cogs as Parallax likes to call them), 512K RAM and 64 GPIO with SmartPin features.
I got my P2 evaluation system (ES) board a few weeks back and designed a couple of P2 ES prototyping wings to go with it.
The first prototyping wing (on the right) is a classic proto board with I/O from two GPIO ports. The other prototyping wing is a breadboard design for faster circuit build and test and features a 3x LED’s and 2x switches
I’ve got a few spare PCB’s which I’ll put on my Tindie store.
January 30, 2020
This week saw the arrival of another big box of PCB’s. A lot of PCB’s. Some old but many new.
Arriving where some new stock of RC2014 prototype board, prototype plus boards and extender boards which I sell on Tindie.
Also in the box where some new board designs. No new RC2014 PCB’s this time but some boards for the ZX Spectrum and Commodore 64 computers. I’ll share more details of these in the coming days and weeks.
Time to break out the soldering iron 🙂
Here’s my Tindies store.
July 19, 2019
I’m please to announce that the enhanced prototype board/PCB for the RC2014 Bus I blogged about back in May is now on Tindie.
Also it’s schematic is here.
May 30, 2019
If you’re into making I/O cards for the RC2014 than this enhanced prototype board might be of interest to you.
It features circuitry (see schematic) to for selectable decoding the I/O address and also gates to generate !IORD and !IOWR signals, as well as two spare OR gates.
The IC’s used are:
74LS32 Quad OR gate
74LS688 Octal (8-bit) magnitude comparator
June 29, 2018
I recently came into possession of a Apple IIe (an enhanced Apple II from the early 80’s) and decided to build a few PCB’s to help get this old warhorse back up in running. The first board designed was an extender card for the Apples expansion card to make testing and fault finding them a little easier. The second PCB was a prototyping board to allow me to build up various test circuits.
Both will be available on Tindie soon
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.
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
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