ADC 18 Click

How does it work?

ADC 18 Click as its foundation uses the MAX22005, a high-performance twelve-channel analog-to-digital converter from Analog Devices. The MAX22005 comes with an integrated 24-bit delta-sigma ADC, input multiplexer, signal conditioning, and control logic block allowing ADC to communicate with MCU through a high-speed serial interface. An integrated delta-sigma ADC is shared between all channels with an integrated 5ppm/°C precision reference. Using high-voltage, zero-drift input amplifiers, standard industrial analog input voltage ranges are converted to the ADC input voltage range.

Input channels can be used as twelve single-ended, six differential, and up to eight multichannel configurable differential inputs. In total, the device supports up to 26 different configurations. The MAX22005 can also be configured as an analog-input current-mode device using an external precision resistor per channel or configurable analog-input using an external precision resistor and low-cost switch per channel. All input ports are robustly protected up to ±36V reverse polarity and ±2kV surge pulses without the need for TVS diodes and factory calibrated with a best-in-class system performance of less than 0.05% FSR Total-Unadjusted-Error (TUE) over temperature.

ADC 18 Click communicates with MCU through a standard SPI interface and operates at clock rates up to 30MHz, for all configurations and information management and acquiring conversion results. In addition, it also uses several mikroBUS™ pins. An active-low reset signal routed on the RST pin of the mikroBUS™ socket activates a hardware reset of the system, while the INT pin on the mikroBUS™ socket represents a standard interrupt feature providing a user with feedback information. It also has an additional data ready interrupt marked as RDY and routed on the AN pin of the mikroBUS™ socket, used to signal when a new ADC conversion result is available in the data register.

This Click board™ can be operated only with a 3.3V logic voltage level. It also has an analog inputs external power supply terminal where it is necessary to bring ±15V to accept ± 10V inputs, whose full-scale range is ± 12.5V. The board must perform appropriate logic voltage level conversion before using 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 18 Click corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns).

Notes	Pin					Pin	Notes
Data Ready	RDY	1	AN	PWM	16	NC
Reset	RST	2	RST	INT	15	INT	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 18 Click electrical specifications

Software Support

We provide a library for the ADC 18 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 18 Click driver.

Key functions

• adc18_set_active_channel This function sets the active channel.

• adc18_start_conversion This function starts the conversion with the selected data rate.

• adc18_read_voltage This function reads RAW ADC value of previous conversion and converts it to voltage.

Example Description

This example demonstrates the use of ADC 18 Click board™ by reading the voltage from 12 analog input single-ended channels.

void application_task ( void ) 
 { 
     static uint8_t channel = ADC18_CH_AI1_SINGLE_ENDED; 
     if ( ADC18_OK == adc18_set_active_channel ( &adc18, channel ) ) 
     { 
         adc18_start_conversion ( &adc18, ADC18_DATA_RATE_225_SPS ); 

         // Waits for the availability of the conversion result 
         while ( adc18_get_rdy_pin ( &adc18 ) ); 

         adc18_stop_conversion ( &adc18 ); 

         float voltage; 
         if ( ADC18_OK == adc18_read_voltage ( &adc18, &voltage ) ) 
         { 
             log_printf ( &logger, "Channel AI%u: %.2f Vrn", channel + 1, voltage ); 
             if ( ++channel > ADC18_CH_AI12_SINGLE_ENDED ) 
             { 
                 channel = ADC18_CH_AI1_SINGLE_ENDED; 
                 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.ADC18

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.