STM Mini Development Board – Unboxed!

STM8-1 No doubt,the STM8S-DISCOVERY is a quick start evaluation board which helps us to discover the STM8 features, and to develop and share your own application.

It is based on an STM8S105 and includes an embedded debugger, ST-LINK, and a touch sensing button. Also, numerous applications are available from the STM8S-Discovery web page.

Recently, I came across an ebay seller’s page and found an exceedingly cheap STM mini development board (definitely not an alternative to the discovery) for one of the 8 bit‐microcontrollers. The little board (based on STM 8S003F3P6) is pretty good, and includes an integrated usb port. I really wasn’t expecting much for the price, but am very impressed with the hardware art.

(STM mini development board)

(STM mini development board)

Unfortunately, what appears to be lacking is the product documentation to guide absolute tyros with ST microcontrollers (I’m not an expert with ST microcontrollers, but have at least pulled off to stick something running well on the microcontroller after a few days spent with some great online tutorials). With a powerful magnifier glass in hand, I sacrificed one of the boards from my collection to recreate the schematic as best I could. Fortunately, the chinese manufacturer (and the reseller) did not scratch off the markings so the schematic can be traced out well.


This minimum system development board is fabricated using smd components, and some of the components are located at the bottom-side of the circuit board. D1 is the ‘power’ LED and D2 works as the ‘user’ LED. Swicth S1 is the ‘reset’ switch. The optional external crystal (Y1/8MHz), however, was not populated on the boards…


The Dark Side

The renowned STM8S Discovery board is pretty feature packed, and includes an integrated ST‐LINK for programming and debugging over USB. The circuit board has been designed so that we can simply snap off the ST LINK part if we like to use the microcontroller on its own. All we need to do is provide a USB A to USB B cable and download the various development tools, datasheets and libraries. The STM8S-DISCOVERY ST-LINK is realized using STM32F103C8T6, portion of the schematic of which (lifted from the original ST document: Doc ID 16361 Rev 3 11 ), is shown here for your quick reference.

But, here in this minimum system development board, it was observed that the on-board usb port is only for the power supply input. So programming can be done through the Single Wire Interface (SWIM) with the help of something like the popular STLinkV2. If you are looking for a small STM8 board for your little project – demands a minuscule board (with built in power supply circuit) to control a few GPIOs – this mini development board is a wise choice. Otherwise, you are moving towards an expensive mistake, I think.



Any Hacking? Not learned about it till date. But may be tomorrow I will revert with some findings if I am lucky enough!


Yes, it possible to implement a software USB microcontroller STM8. I just noticed a very useful article “Software USB port on the STM8”. Here is the link of the 2-part article:

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