WAVEGO-GPIO Control

GPIO Control

Introduction

• GPIO: General-Purpose Input/Output Port (General-purpose input/output).
• In this chapter, you can learn the basic GPIO control on the WAVEGO ESP32.

WAVEGO Driver Board Basic Paramenters

• Main controller: ESP32

  IO high-level voltage	3.3V
  IO output current	12mA
  Processor	Xtensa LX6
  Dual-core Processor	@240MHzSRAM520KB+8MB
  Memory	448KB+4MB

Onboard Device & Interface

IO

• Can be used for simple high and low-level control, but also can be used to read high and low levels, PWM outputs, analog signal inputs, UART communication, IIC communication, and so on.

Multi-fuction Expand Interfaces

• Since ESP32 features better computing power and integrates WIFI Bluetooth and other communication methods, and supports the use of ArduinoIDE for development, we chose ESP32 as the main control chip of WAVEGO, and we lead out the spare IOs on the ESP32 as well as other commonly used IOs to form a multifunctional expansion interface as shown in the figure below.

• LED: There are two RGB LEDs on top of the driver board, numbered 0 and 1 on the demo. If more RGB-LEDs (WS2812) need to be connected, they can be extended from this interface, and accordingly, the numbering starts from 2.
• The control function is shown below:
• LED_NUM: the number of the lamp bead, for example, if you control two of them on the board, then LED_NUM is 0 or 1, if you control the first lamp bead extended on the LED-OUT port, LED_NUM=2.

setSingleLED(LED_NUM, matrix.Color(R, G, B));

LED-OUT(G26)	There are two onboard RGB LEDs on the driver board, which are controlled by the G26 pin, and two WS2812 LEDs are connected in series with this LED-OUT, if you need to connect more RGB LEDs, you can expand them on this interface.
G15	This IO port is for connecting to other modules
G12	Assembly mode is set by default, and the device enters into assembly mode after connecting G12 and 3V3 with DuPont cable.
RX,TX	Corresponding to the UART_0 of ESP32, it can be used to communicate with other devices, for example, it can be connected with TX and RX of Raspberry Pi, and can communicate with each other after connecting to the ground.
TX,RX,GND,5V,5V	It can be used to connect to Raspberry Pi, 5V and GND can be used to supply power to Raspberry Pi, TX, RX can be used to communicate with Raspberry Pi.

Note: When RX, TX is connected to Raspberry Pi TX, RX, the automatic download function can not be activated, if you need to upload a new demo to ESP32, you need to disconnect RX and TX from Raspberry Pi.

IIC

• IIC is a simple, bi-directional two-wire synchronous serial bus developed by Philips that requires only two wires to transfer information between devices connected to the bus.
• The WAVEGO driver board integrates a variety of devices, most of which are controlled using IICs for communicating with other devices, including the ICM20948 Attitude Sensor (0x68), the PCA9685 Servo Control Chip (0x42), the INA219 Voltage Detection (0x40), and the OLED Screen (0x3C).
• Many of the ESP32's GPIOs can be set up as IIC interfaces. The IIC interfaces on the WAVEGO driver board are as follows:

G33	SCL
G32	SDA

• If you want to use other pins while using the wire library, you just need to call:

  Wire.begin(SDA, SCL);

Others

• The information here is only necessary to know if you are doing ESP32-based project development, you don't need to know this if you are only learning about WAVEGO-based features.
• Not all IO interfaces are full-featured, there are also pins with specific functions that are not applicable to specific projects.

GPIO	Input	Output	Notes
0	Pull-up power on	OK	Output PWM signal when powering on, if you pull down when booting up, the ESP32 enters the download mode
1	Connect to TX	OK	Debug the output when guiding
3	OK	Connect to RX	high at power-on
6	x	x	Connect to integrated SPI flash memory
7	x	x	Connect to integrated SPI flash memory
8	x	x	Connect to integrated SPI flash memory
9	x	x	Connect to integrated SPI flash memory
10	x	x	Connect to integrated SPI flash memory
11	x	x	Connect to integrated SPI flash memory
12	OK	OK	If pulled high it fails to start (this is why WAVEGO unplugs the jumper wire used to set the servo assembly center position before powering up)
14	OK	OK	Output the PWM signal when booting up
15	OK	OK	Output the PWM signal when booting up
34	OK	NO	Input only
35	OK	NO	Input only
36	OK	NO	Input only
39	OK	NO	Input only

Buzzer Control

• From the figure, the buzzer is connected to pin 21.
• When BUZ input is high, Buzzer.Q1 does not conduct, no current passes through the buzzer and no sound is emitted;
• When BUZ input is low, Buzzer.Q1 conducts, the buzzer has current through it and emits sound.

New Project

• Open the Arduino IDE, copy the demo for the buzzer into it, and hold down Ctrl+Shift+S on the keyboard to save it:

• Save the newly created project with the filename BUZZER (you can create a new folder to store project files for the Arduino IDE):

• You can find your project in the path folder after you save it successfully. When you save the project, it will automatically create a new folder with the project name, and the .ino file with the same name as the project will be placed in this folder.

Full Demo Codes

#define BUZZER_PIN 21

void setup()
{
  pinMode(BUZZER_PIN,OUTPUT);
}

void loop()
{
  digitalWrite(BUZZER_PIN,LOW);
  delay(500);
  digitalWrite(BUZZER_PIN,HIGH);
  delay(1000);
}

Demo Analysis

• Defines the use of GPIO21 to control the buzzer. GPIO21 is also the pin that controls the onboard buzzer.
  1. define is a macro definition command in C used to define an identifier as a string, where the identifier is called the macro name and the string is the replacement text.
• Usage: #define < macro name/identifier> <string>

#define BUZZER_PIN 21

• Arduino IDE basic framework:

void setup()
{
    
}

void loop()
{
    
}

After running the program, the setup function is run once, and then the loop function is run in a non-stop loop.

Initializes the pin and sets the pin to output.

pinMonde(BUZZER_PIN,OUTPUT);

digitalWrite(), is used to control the high and low level state of the pin, when using GPIO21 to control the buzzer, the buzzer sounds when inputting a low level, and stops when inputting a high level.

digitalWrite(BUZZER_PIN,LOW);
digitalWrite(BUZZER_PIN,HIGH);

Upload Demo

• Open the BUZZER.ino file with Arduino IDE, copy and paste the code into the project, connect the device to the computer with USB, select the development board and port, and click Upload the demo.

Demo Running Effect

• The buzzer sounds for 0.5 seconds after power-up and then stops for 1 second, after which it keeps cycling.