leshy – Less Expensive STM32F0-Hosting Prototypes

Description

This little board is designed to speed up the prototyping process of applications driven by a STM32F030F4P6. The latter is a low-end Cortex M0 controller, really cheap, but more than powerful enough for a whole range of applications.

Its usefulness comes from the general-purpose prototyping area and its carefully aligned and connected on-board peripherals. Source code examples, which work as starting points for various use cases are included in the GitHub repository.

Details

A while ago, I discovered the STM32F020F4P6. It is the lowest-end Cortex-M0 microcontroller ST offers and it is happily supplied by various Chinese stores for 30 to 80 cents per piece. Albeit being very cheap, it offers quite a lot of functionality! It runs at 32 MHz, has 16K of flash and 4K of RAM, an 12 bit ADC, SPI, I2C, a bunch of timers, …

It is a tiny controller, but for most of my applications it's more than enough. Read in some sensors, control some outputs via a state machine, datalog something to a SD card – why should I use a giant controller when I can have a cheap, small and simple solution?

This project started because I wanted to have a nice prototyping platform for that particular controller, just to test some things before I design a real PCB for the project. Yes, Chinese-made boards exist. Yes, I could just step up to F1s and use a cheap “Blue Pill” board like everyone else. But all those readily available boards have, in my opinion, one major flaw. Read more »

Components

1 × STM32F030F4P6 The controller it's all about

2 × Pushbuttons One for reset, one for all the other purposes

6 × LEDs 1 as a power indicator, 5 freely controllable

1 × Micro-SD card holder (type TFP-09)

1 × MCP1700-3302 or compatible (SOT-23) Small 3.3 V LDO

Project Logs

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New revision: a complete overhaul
fruchti • 02/04/2020 at 16:49 • 0 comments

About two years after revision 2, I decided to do a complete redesign of the board. The general form factor stayed the same, but many of the original design's issues could be addressed. Most importantly, revision 3.0 features an optimised prototyping area. Here's what it looks like:

Schematics, layout and code examples can be found on GitHub.

There also is a blog post with details about the whole development process, including a list of all the changes.
New demo project: Soldering iron controller
fruchti • 05/21/2018 at 19:30 • 0 comments

So far this has only been a page for a prototyping board with nothing about actual prototypes. This isn't necessarily a bad thing, but there's no harm in some inspiration for possible uses for the board.That's why I decided to add a small weekend project here: A simple controller for a Hakko-907-style soldering iron (because Chinese fakes of these and the appropriate tips are widely and cheaply available).
For this application, the STM32F030F4P6 has the perfect size with just the right number of pins and absolutely sufficient capabilities. The leshy has just enough prototyping area for the display and the few extra components the controller needs. To be fair, the encoder and jack for the soldering iron wouldn't fit on the PCB, but those look well in their panel-mount configuration here.

Being built over the last weekend, it of course isn't perfect, but I think it has some reusable components for accelerating development. Well, apart as being useful as a soldering iron for me. Code, schematic and documentation are on GitHub.
The second board revision is finished!
fruchti • 11/27/2017 at 18:51 • 0 comments
As my boards start to run out, I had to order new ones. On this occasion, I made some changes to the boards, mainly:
- The SD card can now be switched off via a small MOSFET. An SD card can draw a lot of power for battery-powered applications, so having the option to turn it off is nice. The MOSFET is connected to PA1 and is shorted via J5 per default, so the MOSFET isn't required.
- There's way more silkscreen text. The backside had free room which I used for some helpful labeling.
- Minor improvements of the layout, of course.
The overall look hasn't changed much from
to