ADS1114: Device connections

Hi Andrea,

The ADS1114 can communicate with an Arduino through its I2C interface, acting as a slave device on the I2C bus while the Arduino acts as the master.

You can read about this in more detail in section 9.5 of the data sheet. 

The general procedure is that you would issue I2C commands from the Arduino to write to the ADS1114 registers to configure the part to the mode you will be using the part in, issue conversion starts, configure the PGA, read data from the registers, etc.

Instructions on Writing To and Reading From the Registers can be found in section 9.5.3 of the data sheet. Section 9 gives a detailed description of the device functionality. 

After a conversion is made, the 16-bit data in binary two's complement is stored in the Conversion Register. You would then have the master device issue an I2C command to read the data from the Conversion Register, and you could store the data in an array to then plot it, or manipulate the data in any other way you need to. When the next conversion is done, the data in the conversion register will be replaced with the new data, and this process is repeated as needed.

The ADS1114 can only accept positive voltage values with respect to ground on its input pins.  If the input signal you will be measuring goes to negative voltage values as well, what you could do is to offset your input signal to around halfway of the supply voltage (2.5V if you are using a 5V supply on VDD for example), or to a value that ensures the input pins won't be seeing negative voltages. This could be achieved by using a fully differential amplifier in between your sensor output and the ADC's input pins where Vcm is your offset. 

If you will be doing single-ended measurements (AINP = AIN0, AINN = GND) this restricts the Full Scale Range to only the positive codes (0000h to 7FFFh). The entire +/-FSR (8000h to 7FFFh) is achieved by using differential inputs. 

There are more details involved, but hopefully this will give you a general idea of how to operate the part.

Best Regards,

Angel

Hi Andrea,

The evaluation module is an easy to use and great tool for initial testing of the part.

We have an evaluation module for the ADS1115 which is functionally the same as the ADS1114 but with 4 input pins and a multiplexer instead of two input pins. You can order it and access technical documentation that will help you for your design here: ADS1115EVM-PDK Evaluation board | TI.com

A PCB is recommended once you design the part into your system.

Best Regards