By Blake Felt - [email protected]

ESP32 ADS1115

A component for TI ADS1115 on ESP-IDF. For an example, see https://github.com/Molorius/ESP32-Examples.

To add to a project, type: git submodule add https://github.com/Molorius/esp32-ads1115.git components/ads1115 into the base directory of your project.

The datasheet can be found here.

This has not been tested with more than one ADS1115 connected. Any suggestions or fixes are gladly appreciated.

Table of Contents

• Enumerations
  • ads11115_mux_t
  • ads1115_fsr_t
  • ads1115_sps_t
  • ads1115_mode_t
• Functions
  • ads1115_config
  • ads1115_set_rdy_pin
  • ads1115_set_mux
  • ads1115_set_pga
  • ads1115_set_mode
  • ads1115_set_sps
  • ads1115_set_max_ticks
  • ads1115_get_raw
  • ads1115_get_voltage

Enumerations

enum ads1115_mux_t

The different multiplexer options on the ADS1115.

Values

• ADS1115_MUX_0_1: Connect pins 0 and 1.
• ADS1115_MUX_0_3: Connect pins 0 and 3.
• ADS1115_MUX_1_3: Connect pins 1 and 3.
• ADS1115_MUX_2_3: Connect pins 2 and 3.
• ADS1115_MUX_0_GND: Connect pin 0 to ground.
• ADS1115_MUX_1_GND: Connect pin 1 to ground.
• ADS1115_MUX_2_GND: Connect pin 2 to ground.
• ADS1115_MUX_3_GND: Connect pin 3 to ground.

enum ads1115_fsr_t

The different full-scale resolution options.

Values

• ADS1115_FSR_6_144: 6.144 volts
• ADS1115_FSR_4_096: 4.096 volts
• ADS1115_FSR_2_048: 2.048 volts
• ADS1115_FSR_1_024: 1.024 volts
• ADS1115_FSR_0_512: 0.512 volts
• ADS1115_FSR_0_256: 0.256 volts

enum ads1115_sps_t

The different samples per second, or data rate, options.

Values

• ADS1115_SPS_8: 8 samples per second
• ADS1115_SPS_16: 16 samples per second
• ADS1115_SPS_32: 32 samples per second
• ADS1115_SPS_64: 64 samples per second
• ADS1115_SPS_128: 128 samples per second
• ADS1115_SPS_250: 250 samples per second
• ADS1115_SPS_475: 475 samples per second
• ADS1115_SPS_860: 860 samples per second

enum ads1115_mode_t

Continuous or single-shot mode.

Values

• ADS1115_MODE_CONTINUOUS: continuous mode.
• ADS1115_MODE_SINGLE: single-shot mode.

Functions

ads1115_t ads1115_config(i2c_port_t i2c_port,uint8_t address)

Setup of the device.

Parameters

• i2c_port: the i2c bus number.
• address: the device's i2c address.

Returns

• The configuration file, which is passed to all subsequent functions.

Notes

• This does not setup the i2c bus, this must be done before passing to this function.

void ads1115_set_rdy_pin(ads1115_t* ads,gpio_num_t gpio)

Sets up an optional data-ready pin to verify when conversions are complete. Connect to ALRT/RDY pin on ADS1115.

Parameters

• ads: The configuration file.
• gpio: The esp32 gpio. Do not setup beforehand.

void ads1115_set_mux(ads1115_t* ads,ads1115_mux_t mux)

Sets the pins to be multiplexed.

Parameters

• ads: the configuration file.
• mux: the desired multiplex option (see enumeration).

void ads1115_set_pga(ads1115_t* ads,ads1115_fsr_t fsr)

Sets the full-scale range, or the programmable-gain amplifier.

Parameters

• ads: the configuration file.
• fsr: the desired full-scale range option (see enumeration).

void ads1115_set_mode(ads1115_t* ads,ads1115_mode_t mode)

Sets the read mode.

Paremeters

• ads: the configuration file.
• mode: the desired mode (see enumeration).

Notes

• To end continuous mode, set it to single-shot mode and make one voltage read.

void ads1115_set_sps(ads1115_t* ads,ads1115_sps_t sps)

Sets the sampling speed.

Parameters

• ads: the configuration file.
• sps: the desired samples per second (see enumeration).

void ads1115_set_max_ticks(ads1115_t* ads,TickType_t max_ticks)

Sets the maximum wait ticks for the i2c reads and writes. See the i2c documentation.

Parameters

• ads: the configuration file.
• max_ticks: maximum wait ticks.

int16_t ads1115_get_raw(ads1115_t* ads)

Reads the voltage based on the current configuration.

Parameters

• ads: the configuration file.

Returns

• The 16 bit raw voltage value directly from the ADS1115.

double ads1115_get_voltage(ads1115_t* ads)

Reads the voltage based on the current configuration.

Parameters

• ads: the configuration file.

Returns

• The voltage, based on the current full-scale range. This is just a conversion from the raw value.