DAC Click

How does it work?

DAC Click is based on the MCP4921, a 12-bit DAC with an SPI interface from Microchip. It utilizes a resistive string architecture, with its inherent advantages of low DNL error, low ratio metric temperature coefficient, and fast settling time over an extended temperature range. The analog output is provided on the VOUT screw terminal. The VOUT can swing from approximately 0V to approximately VCC voltage, in the case of this Click board™, 3.3V or 5V. The analog signal on the reference pin of the MCP4921 is utilized to set the reference voltage on the string DAC. The reference voltage can be selected between the VCC and the 4.096V given by the MCP1541 via the REF SEL jumper.

DAC Click uses the SPI serial interface over the mikroBUS™ socket to communicate with the host MCU, with 20MHz clock support. The 12-bit data is sent to the DAC through the SPI interface. This interface is also used to enter the Shutdown mode, during which the supply current is isolated from most of the internal circuitry. The Power-on-Reset (POR) circuit allows the device to continue to have a high-impedance output until a valid command is performed to the DAC registers, thus ensuring a reliable power-up. 

This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the PWR SEL jumper. This way, both 3.3V and 5V capable MCUs can use the communication lines properly. However, the Click board™ comes equipped with a library containing easy-to-use 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 DAC 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	NC
	NC	2	RST	INT	15	NC
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	5V	Power Supply
Ground	GND	8	GND	GND	9	GND	Ground

Onboard settings and indicators

DAC Click electrical specifications

Software Support

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

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

Library Description

This library contains API for DAC Click driver.

Key functions

• This function is used to set output voltage in percents.

• This function is used to set output voltage.

Example Description

This demo example sends digital signal to the outputs and converts it to analog.

 void application_task ( void ) 
 { 
     for ( dac_val = 0; dac_val <= DAC_RESOLUTION; dac_val += DAC_STEP_VALUE ) 
     { 
         dac_set_voltage( &dac, dac_val ); 
         dac_val *= DAC_CALIB_VAL_1; 
         dac_val /= DAC_CALIB_VAL_2; 
         log_printf( &logger, " Current DAC Value: %d mV rn", dac_val ); 

         log_printf( &logger, "----------------------------------rn" ); 

         Delay_ms( 2000 ); 
     } 
 }

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

Other Mikroe Libraries used in the example:

• MikroSDK.Board
• MikroSDK.Log
• Click.Dac

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 MIKROE compilers.

mikroSDK

This Click board™ is supported with mikroSDK – MIKROE 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.