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GPIO Functions on STM8S using Cosmic C and SPL – Blinking and Controlling LED with Push Button

Intermediate

OTHER CONTROLLER

₹500 – ₹1,500

3 – 6 Hours

Partial Kit

GPIO Functions on STM8S using Cosmic C and SPL – Blinking and Controlling LED with Push Button

Learn how to perform general GPIO functions on the STM8S microcontroller using Cosmic C and the Standard Peripheral Library (SPL) by blinking an onboard LED and controlling an external LED with a push-button.

Originally published on CircuitDigest

View original tutorial

Parts You'll Need

This project is sourced from another site, not written by us — this list is our best match of their components against what we stock, not a verified bill of materials. Always check the original blog (linked above) for the actual parts list before buying.

2-Slot 18650 Holder with Protective Cover and On/Off Switch – Case Rs. 109.00
10pcs 5mm RED Diffused Light Emitting Diodes - LEDs Set Rs. 39.00
Jumper Wire 10 Pin Male To Male 20cm Rs. 45.00
400 Points Mini Solderless Prototype PCB Breadboard High Quality Rs. 89.00
MB102 Adjustable Breadboard Power Supply Module (3.3V & 5V) for Arduino & Raspberry Pi Rs. 139.00
Jumper Wire 10 Pin Male To Female 20cm Rs. 45.00

Selected: Rs. 0.00

We don't carry yet: Other Dev Board (Indusboard / Maixduino / misc)
USB Host / Programmer (ISP/USBasp)

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How It Works

This project centers on the STM8S103F3 microcontroller, which interfaces with external hardware using General-Purpose Input/Output (GPIO) pins. At its core, the system operates by configuring specific microcontroller pins as either digital outputs or digital inputs through software routines built with the STM8S Standard Peripheral Library (SPL) and compiled using Cosmic C in an IDE like ST Visual Develop (STVD). When configured as an output, the microcontroller drives voltage high or low to switch an external LED on and off, creating a blinking pattern. When configured as an input, a GPIO pin monitors the state of a connected push-button switch. Using a pull resistor configuration, the input pin detects whether the button is pressed (completing a circuit to change the logic level) or released. The microcontroller reads this input state in real time and uses conditional logic to control the output state of the LED, allowing the push-button to directly toggle the LED's illumination. The ST-Link programmer facilitates uploading this compiled firmware from the development PC directly onto the STM8S103F3 flash memory over the SWIM interface. Connecting wires tie the STM8S development board, ST-Link, LEDs, and push-button switch together into a cohesive working prototype.

Why Build This

Master foundational microcontroller register configurations and GPIO pin management required for advanced embedded systems coursework.

Gain practical experience utilizing industry-standard toolchains like Cosmic C and the STM8S Standard Peripheral Library for hardware control.

Develop reliable embedded logic for reading digital inputs from mechanical switches and driving digital outputs like status LEDs.

Real-World Application

Understanding GPIO configuration, input reading, and output driving is foundational for all embedded systems, serving as the basis for reading sensors, driving indicators, and interfacing with external peripherals in industrial and consumer electronics.

Skills You'll Learn

GPIO configuration

digital input reading

digital output driving

peripheral library utilization

firmware compilation and flashing

switch debouncing logic

Safety Precautions

No specific precautions noted for this build — always follow general electronics safety practices.

Frequently Asked Questions

What is the role of the ST-Link programmer in this setup?

The ST-Link programmer connects your development PC to the STM8S103F3 board, allowing you to transfer the compiled Cosmic C firmware code into the microcontroller's memory.

Why use the Standard Peripheral Library (SPL) instead of raw register manipulation?

The SPL provides a set of pre-written functions that abstract complex register configurations, making it easier and faster to initialize and control GPIO pins without looking up every memory address manually.

Do I need an external power supply for the push-button and LEDs?

No, the components can be powered directly from the voltage supply pins of the STM8S development board, provided current-limiting resistors are used to protect the LEDs.

Gallery

This page is part of Kitkraft's Project Hub — a curated collection of electronics & robotics projects gathered from the maker community to help students and hobbyists discover and learn to build. Kitkraft does not claim authorship of the original project, and makes no representation as to the accuracy, completeness or safety of third-party source material. The summary and "How It Works" explanation above are AI-generated, rewritten with reference to the original tutorial — not a reproduction of it. Full credit and a direct link to the original source are provided above. If you're the original creator and have a concern about how your work is represented here, please contact us and we'll address it promptly.

Kitkraft Project Hub — curated from the maker community, credited at the source.

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