TI Analogue Engineers Pocket reference Book
TTL Logic Level, Fan In and Fan Out
Button - Pull Up and Pull Down Resistor and Tri-State Logic Concept
LED - Notes
Serial Communication - RS 232
Fundamentals of I2C
DC Motor Interface
Servo Motor
I2C RTC DS3231 datasheet Link for Code : https://github.com/eepj/stm32-ds3231