UCMOD on JKTDEV.CO.UK

Refining the UCMOD Architecture

Sat, 19 Sep 2026 21:30:57 +0100

It has been a busy few days. I’ve been attending a number of trade and technology events, dealing with some of the less interesting parts of running a business, and preparing for a few more events during Belfast Tech Week next week.

Doing business in the UK at the moment is not particularly easy, although one of the advantages of being a very small business is that I can remain relatively compact and adapt quickly when necessary.

PICkit 5, GCBASIC and a Logic Green Rabbit Hole

Fri, 28 Aug 2026 23:18:53 +0100

Today I managed to get a little time to test my PICkit 5 programmer with the UCMOD-0 module, mainly by porting the example code I had previously created using Arduino over to plain C using MPLAB in Visual Studio Code.

It isn’t quite working yet.

I can see the TX line flickering on the oscilloscope, and I already know that the receiver code works correctly from my previous test setup using a Raspberry Pi Pico 2 W. That narrows the problem down considerably.

Pruning the Pipeline, Renaming UCMOD and Building an Authentication API

Tue, 25 Aug 2026 23:57:48 +0100

Today was a fairly mixed day, split between rearranging some upcoming development work, tidying up the electronics development pipeline, and starting work on a small authentication API that I expect to reuse across several future projects.

One consequence of reviewing the hardware pipeline was deciding to halt development of the USB-C Shield.

Pruning the Development Pipeline

The USB-C Shield was originally developed largely as a test case while I was exploring EasyEDA rather than KiCad. It served that purpose well, but looking at it again as a potential Protoworks product, it doesn’t really make much sense to continue developing it at the moment.

Defining the Small and Large UCMOD Form Factors

Mon, 24 Aug 2026 23:57:00 +0100

Today was mostly an admin day: accounts, emails, taxes and all the fun stuff that comes with running a business. I could go on a rant, but that’s probably best avoided.

I did, however, manage to improve the Protoworks website slightly. I’ve added Slack integration so that anyone with questions about my products or projects can chat with me directly. I’ll trial it for a few weeks and see whether it improves the customer experience.

Defining the UCMOD Auxiliary Connector

Fri, 21 Aug 2026 20:39:04 +0100

Today I decided to define the UCMOD Auxiliary Connector layout.

UCMOD Connector

As a prelude to designing the UCMOD Auxiliary Connector, here is the current pinout definition for the existing main UCMOD connector.

Pin	Function	Pin	Function
1	GND	2	3V3
3	GND	4	RESERVED
5	I2C_SCL / GPIO0	6	I2C_SDA / GPIO1
7	UART_TX / GPIO2	8	UART_RX / GPIO3
9	SPI_MOSI / GPIO4	10	SPI_MISO / GPIO5
11	SPI_SCK / GPIO6	12	SPI_CS / GPIO7
13	AN0 / GPIO8	14	AN1 / GPIO9
15	AN2 / GPIO10	16	AN3 / GPIO11
17	RESERVED	18	GND
19	3V3	20	GND

There are 12 GPIO pins available through the standard UCMOD connector, with a defined primary function assigned to each where appropriate. These include I2C, UART, SPI and four analogue-capable pins.

Software Testing the UCMOD-0 over RS485

Thu, 20 Aug 2026 23:06:06 +0100

Today’s focus was on the software side of the UCMOD-0 ATtiny1614 module and the Isolated RS485 Building Block Board, creating a basic “Hello World” test program, configuring the ATtiny1614’s clock and brown-out settings, and testing communication over the RS485 bus.

Things went well overall. There was an issue with a jumper wire not being fully seated, which caused instability on the power rail and in turn caused the ATtiny to halt intermittently. Once that was fixed everything looked good.

Programming and Testing the UCMOD-0 with Arduino and UPDI

Wed, 19 Aug 2026 20:27:25 +0100

Today I finally got a chance to do some initial software testing with the UCMOD-0 and the Isolated RS485 Carrier Board.

Things went surprisingly well, all things considered, other than a ten-minute diversion trying to figure out why the obligatory “Hello World” LED blink sketch was failing to blink the LED on the carrier board.

Thankfully, the problem existed between the chair and keyboard — me — rather than with the hardware.

Maker Night and Designing the UCMOD-1

Wed, 19 Aug 2026 00:04:20 +0100

Today I attended a Maker Night at Farset Labs in Belfast. It was a great chance to chat with other makers, shoot the breeze, see what people were working on, and learn a little more about the facilities available at the makerspace.

There appears to be plenty going on, particularly around laser cutting, 3D printing and CNC machining. My own work is somewhat adjacent to much of that these days, being mostly focused on electronics design and coding, but it’s always interesting to see what other people are building and what can be produced with the various tools available at the makerspace.

First Hardware Tests of the UCMOD-0 and RS485 Rev C

Mon, 17 Aug 2026 22:22:44 +0100

Today I received the latest revision of the Isolated RS485 Building Block Board and the first version of the ATtiny1614-based UCMOD-0 microcontroller module.

This was a particularly interesting batch because it gave me the opportunity to test not only the changes made to the RS485 board, but also the basic UCMOD concept in physical hardware for the first time.

RS485 Isolated Board Rev C

Rev C Isolated RS485 Building Block Board

Revision C of the Isolated RS485 board adds a UCMOD connector, an improved input protection circuit based around the TPS259474LRPWR eFuse, and a new DC-to-DC converter.

Tweaking the UCMOD-0 Microcontroller Module

Fri, 14 Aug 2026 22:47:45 +0100

It’s a short update today.

Today I tweaked the ATtiny1614 UCMOD design slightly. The main change was adding a jumper that allows the UPDI programmer’s power line to supply only the microcontroller, rather than powering the entire module and potentially any attached carrier board or other circuitry.

I also adjusted the three-pin UPDI socket to match the header layout used by the Adafruit UPDI Friend. The previous arrangement worked electrically, but hadn’t been laid out with the UPDI Friend’s physical header pin arrangement in mind.

Two Simple Boards for the Just Boards Range

Thu, 13 Aug 2026 23:03:50 +0100

Today I decided to design two simple PCBs for my ‘Just Boards’ range. Unlike most of my other boards, these are intended primarily for user assembly rather than PCB assembly services. They’re deliberately simple, use common components wherever possible, and should require little more than a decent soldering iron to assemble.

The bare PCBs can be ordered from manufacturers such as JLCPCB or PCBWay, while the components themselves are standard parts that can be sourced from Amazon or other electronics suppliers. The aim is to keep these boards inexpensive, accessible and easy to build without requiring solder paste, stencils, hot-air rework equipment or other specialist tools. In most cases, a soldering iron — and perhaps a little Blu Tack to hold components in place while the board is turned over — should be enough.

Expanding the Building Block Ecosystem

Tue, 11 Aug 2026 22:06:44 +0100

Today I sent the following Building Block Boards off to the fab for manufacture:

Rev A of the UCMOD-0 Microcontroller Module, an ATtiny1614-based plug-in module that can be fitted to compatible Building Block Boards to provide them with processing capability.
Rev C of the Isolated RS485 Building Block Board, which includes the revised input protection circuit as well as support for the new UCMOD interface.

I actually skipped manufacturing Rev B of the Isolated RS485 board. That revision had already been designed, but before sending it to manufacture I decided to add the UCMOD header and its associated circuitry, so the design moved directly on to Rev C.

Designing a Modular ATtiny Microcontroller Board

Tue, 04 Aug 2026 00:00:21 +0100

Today I started designing a microcontroller module as part of a larger project that I have been working on.

The first version is based on the Microchip ATtiny1614. The board should also be compatible with the ATtiny1624 and ATtiny3224 in their equivalent 14-pin packages, although there are naturally some differences in the peripherals and capabilities provided by each device.

The module connects to its carrier board through a simple 20-pin, 2 × 10, 0.1-inch socket. This plugs into a corresponding 2 × 10 pin header on the carrier board.