Example Code for ESP32-E-Output Triangular Wave

Hardware Preparation

• ESP32-E (or similar) x 1
• AD9837 DDS Waveform Generator Module x1
• Jumper wires
• Oscilloscope x1

Software Preparation

• Arduino IDE
• Install SDK: click to check the SDK installtion tutorial on FireBeetle ESP32-E Wiki Page
• Download and install the DFRobot AD9837 Library. (About how to install the library?)

Wiring Diagram

Connection description

• AD9837 DAT to controller 23/MOSI
• AD9837 CLK to controller 18/SCK
• AD9837 FSC to controller 25/D2(ssPin in the code)
• AD9837 VCC to controller 3.3V
• AD9837 GND to controller GND
• AD9837 AGND to Oscilloscope GND
• AD9837 OUT to Oscilloscope Signal Input

Although AD9837 supports 3.3~5.5V, its power voltage should be consistent with the controller's level voltage. Since the level of FireBeetle ESP32-E is 3.3V, the VCC should be connected to 3V3. If connecting to maincontroller's VCC(VIN) pin, it will cause the AD9837 to misjudge the level, resulting in data error and output waveform error.`

Sample Code

/*
 * Output triangular wave signal;
 * The amplitude of triangular wave signal is about 0.645V;
 */

#include <DFRobot_AD9837.h>

uint8_t ssPin = D2;
DFRobot_AD9837 AD9837(/* fscPin= */ssPin, /* *pSpi= */&SPI);   //Init an instance. Call class interface by this instance 

void setup(void)
{
  AD9837.begin(/* frequency= */10000000);//Init SPI communication, frequency：SPI communication max frequency
  AD9837.outputTriangle(/* phase= */0, /* freq= */1000.0);//Output phase 0, frequency 1KHz
}

void loop()
{
  delay(100);
}

Result