1. Microcontroller basics
Embedded systems for mortals

2. Lesson 4 Wired communication Parallel vs. Serial Parallel LCD
Serial I2C and SPI

3. Parallel vs. Serial Parallel Serial
Conveying multiple binary digits (bits) simultaneously
Conveys only a single bit at a time
Many wires/traces
(number of electrical conductors)
Typically 1 wire/bit
Less wires/traces
Communication is based on rising and falling edges of a square wave
Examples: ISA, ATA, SCSI, PCI
Examples: UART, I2C, SPI

4. Parallel LCD (4-bit data bus)
Hitachi HD44780
LCD RS pin to digital pin 12
LCD Enable pin to digital pin 11
LCD D4 pin to digital pin 5
LCD D5 pin to digital pin 4
LCD D6 pin to digital pin 3
LCD D7 pin to digital pin 2

5. Parallel LCD (4-bit data bus)
Hitachi HD44780

6. Serial: I2C & SPI I2C (TWI) SPI Pins: SDA (A4), SCL (A5)
Pins: MISO (11), MOSI (12), SCK (13), SS (10/any)
Up to 127 devices. Devices have an address (0x00 to 0x7F) which determines where data is sent/received from. SDA for both sending and receiving
Devices are chosen based on SS (slave select pin). One line for sending (MOSI, master out, slave in) and one for receiving (MISO, master in, slave out). Data can go both ways at the same time
Wire.h
SPI.h
Easier to daisy-chain
Faster

7. I2C/SPI modules
A wide variety of sensors, drivers and modules use serial data to communicate with microcontrollers
PCD8544, Nokia LCD (SPI)
Adafruit library with graphics
Smaller footprint library
MiniOLED display (I2C)
Adafruit library (SSD1306) 128x64 i2c
Wii Nunchuck (I2C)
Library
Example with Processing visualisation
VL53L0X Time-of-Flight Distance Sensor (I2C)
Description