ADC 15 Click

How does it work?

ADC 15 Click as its foundation uses the ADS131M02, a low-power, two-channel, simultaneously sampling, 24-bit, delta-sigma (ΔΣ) analog-to-digital converter (ADC) with a low-drift internal reference voltage from Texas Instruments. The dynamic range, size, feature set, and power consumption are optimized for cost-sensitive applications requiring simultaneous sampling. An integrated negative charge pump allows absolute input voltages as low as -1.3 V, which enables measurements of input signals varying around the ground with a single-ended power supply.

The ADS131M02 features a programmable gain amplifier (PGA) with gains up to 128. An integrated input pre-charge buffer enabled at gains greater than 4 ensures high input impedance at high PGA gain settings. The ADC receives its reference voltage from an integrated 1.2V reference, allowing differential input voltages as large as the reference. Each channel on the ADS131M02 contains a digital decimation filter that demodulates the output of the ΔΣ modulators. The filter enables data rates as high as 32 kSPS per channel in high-resolution mode. The relative phase of the samples can be configured between channels, thus allowing an accurate compensation for the sensor phase response. Offset and gain calibration registers can be programmed to adjust output samples for measured offset and gain errors automatically.

The ADC 15 Click communicates with MCU through a standard SPI interface to read the conversion data, configure and control the ADS131M02, supporting the most common SPI mode - SPI Mode 1. To normally run the ADS131M02, an LVCMOS clock must be continuously provided at the CLKIN pin, which is achieved with the LTC6903 programmable oscillator activated via the CS2 pin routed to the PWM pin on the mikroBUS™ socket. The frequency of the clock can be scaled in conjunction with the power mode to provide a trade-off between power consumption and dynamic range. Selection of the bits in the CLOCK register allows the device to be configured in one of three power modes: high-resolution (HR) mode, low-power (LP) mode, and very low-power (VLP) mode.

In addition, this Click board™ also uses features such as data-ready/interrupt routed to the INT pin on the mikroBUS™ socket, that serves as a flag to the host to indicate that new conversion data are available, and Reset routed to the RST pin that allows for a hardware device reset.

This Click board™ can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before use with MCUs with different logic levels. However, the Click board™ comes equipped with a library containing functions and an example code that can be used, as a reference, for further development.

Specifications

Pinout diagram

This table shows how the pinout on ADC 15 Click corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns).

Notes	Pin					Pin	Notes
	NC	1	AN	PWM	16	CS2	LTC6903 Enable
Reset	RST	2	RST	INT	15	INT	Data-Ready / Interrupt
SPI Chip Select	CS	3	CS	RX	14	NC
SPI Clock	SCK	4	SCK	TX	13	NC
SPI Data OUT	SDO	5	MISO	SCL	12	NC
SPI Data IN	SDI	6	MOSI	SDA	11	NC
Power Supply	3.3V	7	3.3V	5V	10	NC
Ground	GND	8	GND	GND	9	GND	Ground

Onboard settings and indicators

ADC 15 Click electrical specifications

Software Support

We provide a library for the ADC 15 Click as well as a demo application (example), developed using MikroElektronika compilers. The demo can run on all the main MikroElektronika development boards.

Package can be downloaded/installed directly from NECTO Studio Package Manager(recommended way), downloaded from our LibStock™ or found on Mikroe github account.

Library Description

This library contains API for ADC 15 Click driver.

Key functions

• adc15_read_voltage Get voltage value.

• adc15_set_gain Set gain for channel.

• adc15_set_word_len Set word len.

Example Description

This example showcases ability of the click board to read adc data from 2 different channels. It's also configuratable to read data in different output rate, resolutions( word/data len ), and gain.

 void application_task ( void ) 
 { 
     while ( adc15_data_ready( &adc15 ) ); 
     float channel1 = 0; 
     float channel2 = 0; 
     uint16_t status = 0; 
     if ( !adc15_read_voltage( &adc15, &status, &channel1, &channel2 ) ) 
     { 
         log_printf( &logger, " > Status: 0x%.4Xrn", status ); 
         log_printf( &logger, " > V ch1: %frn", channel1 ); 
         log_printf( &logger, " > V ch2: %frn", channel2 );     
         log_printf( &logger, "************************rn" ); 
         Delay_ms( 1000 ); 
     } 
 }

The full application code, and ready to use projects can be installed directly from NECTO Studio Package Manager(recommended way), downloaded from our LibStock™ or found on Mikroe github account.

Other Mikroe Libraries used in the example:

• MikroSDK.Board
• MikroSDK.Log
• Click.ADC15

Additional notes and informations

Depending on the development board you are using, you may need USB UART click, USB UART 2 Click or RS232 Click to connect to your PC, for development systems with no UART to USB interface available on the board. UART terminal is available in all MikroElektronika compilers.

mikroSDK

This Click board™ is supported with mikroSDK - MikroElektronika Software Development Kit. To ensure proper operation of mikroSDK compliant Click board™ demo applications, mikroSDK should be downloaded from the LibStock and installed for the compiler you are using.

For more information about mikroSDK, visit the official page.