Part 8 of a microcontroller tutorial series moves beyond blinking LEDs by introducing real-world hardware peripherals. The author describes a custom docking board featuring a 4x20 HD44780 LCD, 4x4 button matrix, LEDs, DIP switches, and an ADC potentiometer for AVR and STM32 experiments. The main focus is driving the HD44780 LCD in 4-bit mode: wiring, initialization sequence, calibrating microsecond and millisecond software delays, and using the busy flag to speed up display writes by ~33%. Complete AVR C code is provided for lcd_init, lcd_display, lcd_putc, and delay functions, along with oscilloscope signal analysis and notes on GPIO data corruption risks for both AVR and STM32.
Table of contents
When 2 LEDs Just Don't Cut It Anymore4 x 20 LCD Character Display4 x 4 Button MatrixLEDsConfiguration SwitchesADC (Analog to Digital Converter) PotentiometerFirst Step - Adding An LCD DisplayTangent: Software Delays - MillisecondsTangent: Software Delays - MicrosecondsBut What About The Included Delay Functions?Back To Our LCD DisplayLCD InitializationLCD Put StringLCD Clear DisplayThe LCD Source Code - AVR VersionBut Wait, There's More!A Little Trick For Waiting EfficientlyLCD-SpeakSome Details As Seen On The ScopeDo We Have Any Potential Data Corruption Issues - AVR Version?The LCD Source Code - STM32 VersionDo We Have Any Potential Data Corruption Issues - STM32 Version?Next1 Impression