MCU Interfaces Introduction

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Introduction to MCU interfaces.

MCU Interfaces introduction

GPIO (General Purpose I/O)

Each IO pad drive/sink ~25mA, Entire Chip drive/sink ~200mA

ADC (Analog Digital Converter)

Vin is input voltage for ADC to sample

Vref is reference voltage for ADC to compare with Vin

2-bit ADC

12-bit ADC : output is a 12-bit binary code, so its value = 0 ~ 4095

Direct-Conversion ADC

Successive-Approximation ADC

Sigma-Delta ADC

DAC (Digital to Analog Converter)

Introduction to Digital-Analog Conversion

Binary-Weighted Resistor DAC

PWM (Pulse Width Modulation)

CMR >= CNR: PWM output high
CMR < CNR: PWM output low

PWM Frequency = PWM_Clock/(prescale)*(clock divider)/ CNR

Duty ratio = CMR /CNR

I2C (Inter-Integrated Circuit bus)

I2C bus 簡介

SPI (Serial peripheral interface)

Introduction to SPI Interface
4-wire SPI devices have four signals:

  • CS : Chip select
  • SCLK: SPI Clock
  • MOSI: Master out, slave in
  • MISO: Master in, slave out

Main and a Subnode:

Multi-Subnodes:

Daisy-Chain Method:

SPI Mode 0, CPOL = 0, CPHA = 0: CLK idle state = low, data sampled on rising edge and shifted on falling edge.

I2S (Inter-IC Sound bus)

Introduction to the I2S Interface

UART（Universal Asynchronous Receiver/Transmitter）序列埠

BASICS OF UART COMMUNICATION

Protocol 通訊協定

  • Standard Packet : 8 data bits, even parity, 1 stop bit
    • If the parity bit is a 0 (even parity), the 1 bits in the data frame should total to an even number.
    • If the parity bit is a 1 (odd parity), the 1 bits in the data frame should total to an odd number. RS232 的Vpp電壓較高，有 6V~30V；UART 則是較低的 3.3V 或 5V
      RS232 為負邏輯， UART 為正邏輯，因此兩者波形是反相的
      Baud Rate



This site was last updated October 07, 2024.