Example Code for Arduino-Output a Triangle Wave

Hardware Preparation

• DFRduino UNO R3 + Gravity IO Expansion Shield * 1
• Gravity: MCP4725 12-Bit I2C DAC Module * 1
• Gravity 4P sensor wire (comes with Gravity 12-bit DAC Module) * 1
• Digital multimeter (optional) * 1
• Oscilloscope (optional) * 1

Software Preparation

• Arduino IDE: Click to Download Arduino IDE
• Search and install the 'DFRobot_MCP4725' library in the library manager of Arduino IDE.
• Or download the .zip library in via Github and install the .zip library in Arduino IDE. How to install .zip library?

Wiring Diagram

Other Preparation Work

• Set the I2C address to 0x60 with the ADDR switch. For I2C address 0x61, you need to modify the first parameter of the DAC.init () function in the code below.
• Open Arduino IDE, upload the following sample code to the Arduino UNO, and use a oscilloscope to measure the output voltage of VOUT.
• The user can modify the parameter in DAC.outputTriangle () to change the amplitude, frequency, DC offset and duty cycle of the triangular wave.

Sample Code

/*
 * file OutputVoltage.ino
 *
 * @ https://github.com/DFRobot/DFRobot_MCP4725
 *
 * connect MCP4725 I2C interface with your board (please reference board compatibility)
 *
 * Output a constant voltage value and print through the serial port.
 *
 * Copyright   [DFRobot](https://www.dfrobot.com), 2016
 * Copyright   GNU Lesser General Public License
 *
 * version  V1.0
 * date  2018-1-25
 */
#include "DFRobot_MCP4725.h"
#define  REF_VOLTAGE    5000

DFRobot_MCP4725 DAC;

void setup(void) {
  Serial.begin(115200);
  /* MCP4725A0_address is 0x60 or 0x61
   * MCP4725A0_IIC_Address0 -->0x60
   * MCP4725A0_IIC_Address1 -->0x61
   */
  DAC.init(MCP4725A0_IIC_Address0, REF_VOLTAGE);
}

void loop(void) {
  /*Output amplitude 5000mv, frequency 10HZ,
   *the rise of the entire cycle accounted for 50% of the DC offset 0mv triangular wave.
   */
  DAC.outputTriangle(5000,10,0,50);
}

Result

• A full triangular wave of 5V (peak-to-peak), 10Hz, duty cycle of 50% without DC bias can be observed

Additional Information

/**
   * @fn outputTriangle
   * @brief  Output a sine wave.    
   * @param  amp amp value, output triangular wave amplitude range 0-5000mv
   * @param  freq freq value, output the triangle wave frequency
   * @param  offset offset value, output the DC offset of the triangle wave
   * @param  dutyCycle dutyCycle value, set the rising percentage of the triangle wave as a percentage of the entire cycle.
   * @n      Value range 0-100 (0 for only the decline of 100, only the rise of paragraph)
   * @return None
   */
  void outputTriangle(uint16_t amp, uint16_t freq, uint16_t offset, uint8_t dutyCycle);

• Change the dutyCycle to 0 while the other parameters remain the same. That is "DAC.outputTriangle (5000,10,0,0)", which can generate a 10Hz sawtooth wave of 5V in amplitude.