ADS 1015 Sampling Rate

Question

I recently got an ADS 1015 (in order to make high frequency measurement of a voltage accros a capacitor). The datasheet specified 3.3 kSPS (Sample per seconds). However I only get around 500SPS maximum. And after looking all around, I've found several ressources which talked about a register override... However, I'm not an expert in this field and need your help!

Here is the code I use to test the sampling rate (using an Arduino nano, arduino code is a C++ variant):

  #include <Wire.h>
  #include <Adafruit_ADS1015.h>
  #include <SPI.h>
  
  
  
   
  Adafruit_ADS1015 ADS_0(0x48);
  
  int i = 0;
  long results = 0;
   
  void setup(void)
  {
    Serial.begin(9600);
  
  
  
    
          // CODE FOUND ON THE INTERNET BUT REJECT ERROR BC OF readRegister function not defined... However, I haven't found any library missing... Strange ---------------
           const uint8_t adcAddress = 0x48;
           const uint8_t configRegister = 0x01;
           uint16_t configValue = readRegister( adcAddress, configRegister );
           
           Serial.print( "read config value 0x" );
           Serial.println( configValue, HEX );
           
           configValue = ( configValue & !ADS1015_REG_CONFIG_DR_MASK) | ADS1015_REG_CONFIG_DR_3300SPS;
           writeRegister( adcAddress, configRegister, configValue );
        
           Serial.print( "sent config value 0x" );
           Serial.println( configValue, HEX );
        
           configValue = readRegister( adcAddress, configRegister );
        
           Serial.print( "verifying by rereading config value 0x" );
           Serial.println( configValue, HEX );
           // -------------------------------------------------------------
  
  
    ads1015.begin();
  }
  
  
   
  void loop(void)
  {
    int i=0;
    long depart = micros();
    while(i != 1000) {
        i++;
        results = ads1015.readADC_SingleEnded(0);
    }
    Serial.println(micros() - depart); 
  }

This code return about 2,000,000 which correspond to 2 sec or 500 Hz sampling rate...

Thanks in advance, ~TBD

Answer 1

According to the datasheet I think you have to first set MODE to 0 (Continuous-conversion mode) and DR to 0b111 in the Config Register (pg 24).

Then you can probably use an ISR on ALERT/RDY pin (after proper configuration - pg 15) and read the data each time the interrupt is triggered.

Page 15:

The ALERT/RDY pin can also be configured as a conversion ready pin. Set the most-significant bit of the Hi_thresh register to 1 and the most-significant bit of Lo_thresh register to 0 to enable the pin as a conversion ready pin.