November 2011 Doc ID 022506 Rev 1 1/10

AN4014

Application Note

Adjustable LED blinking frequency

using a potentiometer and STM8SVLDISCOVERY

Application overview

This document introduces a very simple application example which is ideal for beginners to

learn about the STM8SVLDISCOVERY and its programming environment.

This application adjusts the blinking frequency of a string of 4 LEDs using a potentiometer.

The ADC measures the analog voltage present at the potentiometer bridge, and the blinking

frequency of the LEDs is adjusted accordingly.

This application automatically starts as soon as the STM8SVLDISCOVERY is powered-up

through a standard USB cable connected to the host PC, and the LEDs start blinking at a

speed dependant on the potentiometer position.

Note: Additional hardware is required to run this application.

Built around the STM8S003K3T6, the STM8SVLDISCOVERY allows evaluation of the main

features of all the STM8S Value line MCUs.

Reference documents

■ STM8SVLDISCOVERY user manual (UM1482)

■ STM8SVLDISCOVERY getting started (UM1480)

■ Developing and debugging your STM8S application code user manual (UM0834)

■ STM8S003 datasheet

■ STM8S reference manual (RM0016)

www.st.com

Contents AN4014

2/10 Doc ID 022506 Rev 1

Contents

1 Application description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

1.1 Hardware required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

1.2 Application schematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

1.3 Application principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2 Software description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.1 Touch sensing library configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.2 Standard STM8S standard firmware library configuration . . . . . . . . . . . . . 8

2.3 Application software flowcharts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.3.1 Main loop flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.3.2 ExtraCode_StateMachine flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

3 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12