How to Use M5_ADS1100: Examples, Pinouts, and Specs

The M5_ADS1100 is a high-precision, 16-bit analog-to-digital converter (ADC) that communicates via the I2C protocol. It is designed for low-power applications, making it an excellent choice for battery-powered devices. The M5_ADS1100 is capable of converting analog signals into precise digital values, which makes it ideal for interfacing with sensors and other analog devices.

• Sensor data acquisition (e.g., temperature, pressure, light sensors)
• Battery monitoring systems
• Portable medical devices
• Industrial process control
• Data logging systems

The M5_ADS1100 offers the following key technical features:

The M5_ADS1100 is typically available in an 8-pin package. Below is the pinout and description:

1. Power Supply: Connect the VDD pin to a stable power source (2.7V to 5.5V) and the GND pin to ground.
2. I2C Communication: Connect the SCL and SDA pins to the corresponding I2C lines of your microcontroller. Use pull-up resistors (typically 4.7kΩ) on both lines.
3. Address Configuration: Use the A0 and A1 pins to set the I2C address. These pins can be connected to VDD or GND to configure the address.
4. Analog Input: Connect the analog signal to be measured to the input pin of the ADC (refer to the datasheet for specific input pin details).

• Input Voltage Range: Ensure the input signal does not exceed the supply voltage (VDD). Use a voltage divider or buffer circuit if necessary.
• I2C Pull-Up Resistors: Always include pull-up resistors on the SCL and SDA lines to ensure proper I2C communication.
• Bypass Capacitor: Place a 0.1µF ceramic capacitor close to the VDD pin to filter out noise.
• Data Rate: Choose an appropriate data rate (8 SPS to 128 SPS) based on your application's requirements for speed and resolution.

Below is an example of how to interface the M5_ADS1100 with an Arduino UNO using the Wire library:

#include <Wire.h>

#define ADS1100_ADDRESS 0x48  // Default I2C address of the M5_ADS1100

void setup() {
  Wire.begin();  // Initialize I2C communication
  Serial.begin(9600);  // Initialize serial communication for debugging

  // Configure the ADS1100 (e.g., set data rate and gain)
  Wire.beginTransmission(ADS1100_ADDRESS);
  Wire.write(0x8C);  // Configuration byte: 16-bit, 128 SPS, gain = 1
  Wire.endTransmission();
}

void loop() {
  int16_t adcValue = readADS1100();  // Read ADC value
  float voltage = (adcValue * 5.0) / 32768.0;  // Convert to voltage (assuming VDD = 5V)

  Serial.print("ADC Value: ");
  Serial.print(adcValue);
  Serial.print(" | Voltage: ");
  Serial.println(voltage, 3);  // Print voltage with 3 decimal places

  delay(1000);  // Wait 1 second before the next reading
}

int16_t readADS1100() {
  Wire.requestFrom(ADS1100_ADDRESS, 2);  // Request 2 bytes from the ADC
  while (Wire.available() < 2);  // Wait for data to be available

  uint8_t msb = Wire.read();  // Most significant byte
  uint8_t lsb = Wire.read();  // Least significant byte

  // Combine the two bytes into a 16-bit value
  return (int16_t)((msb << 8) | lsb);
}

1. No I2C Communication:

   • Ensure the SCL and SDA lines have proper pull-up resistors (4.7kΩ recommended).
   • Verify the I2C address matches the configuration of the A0 and A1 pins.
   • Check the wiring for loose or incorrect connections.

2. Incorrect ADC Readings:

   • Ensure the input voltage is within the specified range (0V to VDD).
   • Verify the configuration byte sent to the ADS1100 matches your desired settings.
   • Check for noise or interference on the analog input signal.

3. Device Not Detected:

   • Use an I2C scanner sketch to confirm the device's address.
   • Ensure the power supply voltage is within the specified range (2.7V to 5.5V).

Q: Can the M5_ADS1100 measure negative voltages?
A: No, the M5_ADS1100 can only measure voltages in the range of 0V to VDD. For differential measurements, refer to the datasheet for specific configurations.

Q: What is the maximum sampling rate of the M5_ADS1100?
A: The maximum sampling rate is 128 samples per second (SPS).

Q: Do I need an external clock for the M5_ADS1100?
A: No, the M5_ADS1100 has an internal clock and does not require an external clock source.