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.
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.
It’s been a while since we published any thing new for the RC2014 architecture.
This is a simple combined ROM and RAM card designed to work with the RC2014 bus. This is an experimenters board. There is no fancy memory paging etc., it’s simple memory architecture was designed to be flexible and allow the user to experiment with other CPU architectures on the RC2014 bus. It was originally designed to work with our 8052 CPU.
enhanced RC2014 bus
Selectable memory* options 8K, 16K or 32K
Board can be used as RAM only or ROM only or both.
Options for nMRD/nMWR or nRD/nWR signals
Option for 27C512 with Hi/Lo ROM (A15) select
IC Decoder 74xx138 using A15/A14/A13 (with extra options for A13 & A14)
8 or 16-bit wide data bus**
moveable memory positions (i.e. ROM can be at top or bottom memory space)
A couple of important notes:
* Both ROM and RAM memories must be the same size.
** see explanation below
The option for either nMRD and nMWR (nRD and nWR or’ed with nMREQ) signals or nRD and nWR only signals when IC3 (74xx32) is fitted or not fitted allows for experimenting with other CPU Read/Write architectures.
Notably, the enhanced RC2014 bus features a 16-bit data bus. The card can use this enhancement by allowing the selection of the high or low 8-bit portion of 16-bit data bus. This allows the user to experiment with 16-bit CPU’s such as 68000 or 8086 when two cards are used together.
I’ve always found application notes to be great places to expand your knowledge and understanding. Microchip have released or rather re-released a handful of power electronics related notes this month:
It’s not very often that I comment on current events but the Coronavirus or COVID-19 or SARS-Cor-19 is too big a world event not to have some views about. As a maker and also a professional (cough) engineer I’ve been intrigued by the maker community’s response to these events. We’ve seen makers use their faculties to make face masks and face shields using 3D printers, sewing machines etc. not for themselves but for their wider local community and their local health professionals to help protect others against the spread of the virus.
There are many makers and maker companies that have been very proactive in this, just naming a few, companies like Adafruit have lead the way and their blog has many posts. Other useful sites I found are:
Maker communities such as Hackaday and Instructables also have many useful posts. As well as the blog entries themselves, the various comment section are full of very interesting points made by reverent professionals, as well as interesting details and suggestions by other interested parties. Below is a short list of some of the other links found:
And finally, its also the call to arms by many governments to their countries biggest or best industrial companies to help eleaviate their medical equipment shortages. The mainstream media have been quick to jump on these stories of Formula 1 teams, big defence and big consumer companies banding together to rapidily design and manufacture the much needed medical equipments. Others have asked why their countries are not doing the same or enacting war time or emergency powers to allow manufactures to quickly add their manufacturing might to the effort.
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.
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.
When the ZX Spectrum came out in 1982 the options for data storage on home computers were very limited. You usually had the choice of audio cassette tape or floppy disk. The ZX Spectrum initially came with audio cassette storage via an external cassette player/recorder. Sinclair Research would develop a variation of tape storage in their microdrive system via their Interface 1 add-on and it was only very much later that floppy disk storage would appear as a add-on option (i.e. DISCiPLE drive) or as a official computer model (the ZX Spectrum +3)
Now, lets fast forward to the present. Audio tape cassettes and floppy disks are very much a thing of the past and getting new blank tapes or disks is difficult to almost impossible.
However all is not lost as the retro community has been very busy in the intervening years and has come up with many alternatives to tape and disk storage. These alternatives are usually based on either Compact Flash or SD-Card. Below is a short list of some DIY projects: