Introduction to Lichuang EDA

** If there is a mistake , Thank you for correcting **

If there is a mistake , Thank you for correcting , Please send a private message to the blogger , There is a red envelope for hard work , Worship “ one-word teacher ”.

Please find the paragraphs you need according to the table of contents

Introduction ： This blog is organized for individuals EDA Learning notes , If there is a mistake , Thank you for correcting . System learning , Welcome to continue to pay attention , Follow up updates ~
Java communication qq Group 383245788. There are some resources and leaders in the group , Welcome to exchange .

This article aims to learn and communicate , Personal learning experience of basic circuit design

Reference video Lichuang B Stand by the official
https://www.bilibili.com/video/BV1WJ411W7j1

The article may be a little watery , Self use ！！！

EDA course

Core board “ Small and fine ”, Although the circuit is not complicated , But it basically covers all kinds of commonly used circuits
STM32 Abundant resources , There's a lot of information , High cost performance
STM32F103RCT6 stay STM32 The series is a single chip microcomputer with a small number of pins but complete functions
STM32 The core board can be directly used to learn MCU program design
STM32 The core board can complete the entry-level experiment / Intermediate experiment / Complex experiments, etc., at least 20 Species experiment

Traditional circuit design

This process

stm32 Core board

Learning goals

• Understand what is STM32 chip
• understand STM32 Each circuit module of the core board

stm32 Introduce

STM32 Chip introduction
ST The company is based on ARM company 2006 , launched in Cortex-M3 kernel , On 2007 Introduced in the STM32 Series MCU .Cortex-M3 The computing power of the kernel is 1.25DMIPS/MHz, and ARM7TDMI Only 0.95DMIPS/MHz. This tutorial uses STM32 Have 1us The double 12 position ADC,4MBit/S Of UART,18MBit/S Of SPI,18MHz Of I/O Flipping speed , what's more STM32 stay 72MHz When working, the power consumption is only 36mA( All peripherals are working ), While the power consumption during standby is only 2uA.
And because of STM32 Rich peripherals 、 Powerful development tools 、 A simple firmware library , stay 32 Bit micro control selection ,STM32 It has become the first choice of engineers . According to statistics , from 2007 Year to 2016 year ,STM32 Cumulative shipment 20 Million star , Ten years ST The market share in China has increased from 2% Growth to 14%.isuppli Of 2016 The market report in the second half of the year shows , China's Cortex-M market ,STM32 Market share 45.8%

Communication download circuit

Communications - In addition to the program download function, the download module , He also served as “ correspondent ” Role , That is, through communication - Download module to realize computer and STM32 Communication between . in addition , Communications - The download module is also STM32 The core board provides 5V Power supply , It should be noted that , Communications - The download module can output 5V voltage , You can also output 3.3V voltage , therefore , Using communication - Download the module and STM32 When the connection , Need to communicate - Turn the power output switch of the download module to 5V gear .

Power conversion circuit

The power conversion circuit will 5V The input voltage is converted to 3.3V Output voltage . Communications - Download module 5V And STM32 Core board circuit 5V Network connection , diode D1 (SS210) The function of is to prevent STM32 Core board communication - Download module reverse power supply , About... Will be generated on the diode 0.4V Forward voltage difference , Therefore, low voltage differential linear regulated power supply U2(AMS1117-3.3 Of ) Input end (Vin) The voltage of is not 5V, It is 4.6V about . Through the step-down of low-voltage differential linear regulated power supply , Will be in U2 The output of the (Vout) Produce a 3.3V The voltage of . For debugging convenience , Power conversion circuit is designed 3 A test point , Namely 5V、3V3 and GND.

JTAG/SWD Debug the interface circuit

JTAG/SWD The debugging interface circuit adopts standard JTAG Connection method , This connection is compatible SWD Interface , because SWD Just four wires (SWCLK、SWDIO、VCC and GND). It should be noted that , The interface circuit is INK or ST-Link Provide 3.3V The power supply , therefore , Can't pass LINK or ST-Link Yes STM32 The core board is used for power supply , It is STM32 The core board is LINK or ST-Link Power supply .JLINK and ST-Link Not only can you download programs , You can also be right about STM32 On line debugging of microcontroller .

Independent key circuit
STM32 There are three independent buttons on the core board , Namely KEY1、KEY2 and KEY3, Each button is connected in parallel with a capacitor , And through a 10K The resistance is connected to 3.3V Power network . therefore , When the key is not pressed , Input to STM32 The voltage of micro control is high , When the key is pressed , Input to STM32 The voltage of micro control is low .KEY1、KEY2 and KEY3 Connected separately at STM32F103RCT6 Of PC1、PC2 and PAO On the pin .

OLED Display interface circuit
STM32 The core board can communicate - The download module displays data on the computer , It can also be carried on board OLED The interface circuit of the display screen is externally connected with a OLED The display screen displays data , The interface circuit is OLED The display provides 3.3V The power supply .

Crystal oscillator circuit

STM32 The microcontroller has a very powerful clock system , In addition to the built-in high-precision and low precision clock system , Readers can also connect the crystal oscillator , by STM32 Microcontroller provides high precision and low precision clock system .
The figure below shows the external crystal oscillator circuit , among Y1 by 8MHz Crystal oscillator , Connected to the clock system HSE( External high-speed clock ),Y2 by 32.768MHz Crystal oscillator , Connected to the clock system LSE( External low speed clock ).

LED circuit
Except that it is marked PWR Power indication of the LED Outside ,STM32 There are two more on the core board LED,LD1 For blue ,LD2 It's green , Every LED Separate with a 330Q Connect the resistor in series to STM32F103RCT6 On the pin of the chip , stay LED In circuit , Resistance plays the role of partial voltage and current limiting .LD1 and LD2 Connected separately at STM32F103RCT6 Of PC5 and PC4 On the pin .

STM32 Microcontroller circuit

STM32 The microcontroller circuit is STM32 The core part of the core board , from STM32 Filter circuit 、STM32 Micro controller 、 Reset circuit 、 The starting mode selection circuit consists of .

External expansion pin

STM32 On the core board STM32F103RCT6 All in all 51 General purpose IO, Namely PAO_15、PBO15、PCO_15、PD02, among PC14、PC15 Connecting external 32.768KHz Crystal oscillator ,PDO、PD1 Connecting external 8MHz Crystal oscillator , In addition to this 4 One pin ,STM32 Core board pass J1、J2、J3 Three sets of needles lead out the rest 47 General purpose IO.

stm32 The development board can be used for experiments

STM32 Core board program download and verification

• Master communication - Download module pair STM32 The method of downloading programs from the core board
• Master through ST-Link Yes STM32 The method of downloading programs from the core board
• understand STM32 Working principle of core board

preparation

Will communicate - The download module is connected to STM32 Core board
install CH340 drive
adopt MCUISP Download program
View the received data through the serial port assistant
see STM32 Core board working state
adopt ST-Link Download program

Software, etc. then sort out the network disk , Post here . Which steps are not familiar with ,B Station many video tutorials .