Explore the flexibility of digital potentiometer with AD5175 and TM4C129ENCPDT
Experience smooth digital voltage control
Published Aug 23, 2023
Click board™
DIGI POT 7 Click
Dev. board
Fusion for Tiva v8
Compiler
NECTO Studio
MCU
TM4C129ENCPDT
Facilitate precise control and adjustment of resistance values in a wide range of applications
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Hardware Overview
How does it work?
DIGI POT 7 Click is based on the AD5175, a single-channel 1024-position digital rheostat, with less than ±1% end-to-end resistor tolerance error and a 50-time programmable (50-TP) wiper memory from Analog Devices. It possesses one RDAC register that determines the resistor Wiper position and acts as a scratchpad register allowing unlimited resistance settings. The RDAC register can be programmed with any position set using the serial interface. When a desirable Wiper position is found, this value can be stored in a 50-TP memory register. Besides, the Wiper position is always restored to that position for subsequent Power-Up. The storing of 50-TP data takes approximately 350 ms, and during this time, the AD5175 is locked and doesn't acknowledge any new command preventing any changes from taking place. The nominal resistance between terminal W and terminal A is 10kΩ with 1024-tap
points accessed by the Wiper terminal, while in the Zero-Scale condition, a total Wiper resistance of 120Ω is present. The 10-bit data inside the RDAC register is decoded to select one of the 1024 possible Wiper settings. The AD5175 also provides the possibility of the Shutdown feature by executing the software shutdown command. This feature places the RDAC register in a Zero-Power-Consumption state where terminal A is disconnected from the Wiper terminal. The AD5175 can be removed from Shutdown Mode by executing Software Shutdown Command or performing the Hardware Reset feature. DIGI POT 7 click communicates with MCU using the standard I2C 2-Wire interface, with a clock frequency up to 100kHz in the Standard and 400kHz in the Fast Mode. Besides, it also allows the choice of the least significant bit (LSB) of its I2C slave address by positioning the SMD jumper
labeled as ADDR SEL to an appropriate position marked as 0 and 1. This Click board™ can be reset via software by calling the Reset command that loads the RDAC register with the contents of the most recently programmed 50-TP memory location. This register loads with mid-scale if no 50-TP memory location has been previously programmed. It also can be reset through the Hardware Reset pin, labeled as RST on the mikroBUS™ socket, by putting this pin in a logic low state. This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the VCC SEL jumper. This way, both 3.3V and 5V capable MCUs can use the communication lines properly. Also, this 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.
Features overview
Development board
Fusion for TIVA v8 is a development board specially designed for the needs of rapid development of embedded applications. It supports a wide range of microcontrollers, such as different 32-bit ARM® Cortex®-M based MCUs from Texas Instruments, regardless of their number of pins, and a broad set of unique functions, such as the first-ever embedded debugger/programmer over a WiFi network. The development board is well organized and designed so that the end-user has all the necessary elements, such as switches, buttons, indicators, connectors, and others, in one place. Thanks to innovative manufacturing technology, Fusion for TIVA v8 provides a fluid and immersive working experience, allowing access
anywhere and under any circumstances at any time. Each part of the Fusion for TIVA v8 development board contains the components necessary for the most efficient operation of the same board. An advanced integrated CODEGRIP programmer/debugger module offers many valuable programming/debugging options, including support for JTAG, SWD, and SWO Trace (Single Wire Output)), and seamless integration with the Mikroe software environment. Besides, it also includes a clean and regulated power supply module for the development board. It can use a wide range of external power sources, including a battery, an external 12V power supply, and a power source via the USB Type-C (USB-C) connector.
Communication options such as USB-UART, USB HOST/DEVICE, CAN (on the MCU card, if supported), and Ethernet is also included. In addition, it also has the well-established mikroBUS™ standard, a standardized socket for the MCU card (SiBRAIN standard), and two display options for the TFT board line of products and character-based LCD. Fusion for TIVA v8 is an integral part of the Mikroe ecosystem for rapid development. Natively supported by Mikroe software tools, it covers many aspects of prototyping and development thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.
Microcontroller Overview
MCU Card / MCU
Type
8th Generation
Architecture
ARM Cortex-M4
MCU Memory (KB)
1024
Silicon Vendor
Texas Instruments
Pin count
128
RAM (Bytes)
262144
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Click board™ Schematic
Step by step
Project assembly
Start by selecting your development board and Click board™. Begin with the Fusion for Tiva v8 as your development board.
Track your results in real time
Application Output
1. Application Output - In Debug mode, the 'Application Output' window enables real-time data monitoring, offering direct insight into execution results. Ensure proper data display by configuring the environment correctly using the provided tutorial.
2. UART Terminal - Use the UART Terminal to monitor data transmission via a USB to UART converter, allowing direct communication between the Click board™ and your development system. Configure the baud rate and other serial settings according to your project's requirements to ensure proper functionality. For step-by-step setup instructions, refer to the provided tutorial.
3. Plot Output - The Plot feature offers a powerful way to visualize real-time sensor data, enabling trend analysis, debugging, and comparison of multiple data points. To set it up correctly, follow the provided tutorial, which includes a step-by-step example of using the Plot feature to display Click board™ readings. To use the Plot feature in your code, use the function: plot(*insert_graph_name*, variable_name);. This is a general format, and it is up to the user to replace 'insert_graph_name' with the actual graph name and 'variable_name' with the parameter to be displayed.
Software Support
Library Description
This library contains API for DIGI POT 7 Click driver.
Key functions:
digipot7_hw_reset- Hardware reset functiondigipot7_read_rdac- The function read a 10-bit RDAC datadigipot7_write_rdac- The function writes a 10-bit RDAC data
Open Source
Code example
The complete application code and a ready-to-use project are available through the NECTO Studio Package Manager for direct installation in the NECTO Studio. The application code can also be found on the MIKROE GitHub account.
/*!
* @file main.c
* @brief DIGIPOT7 Click example
*
* # Description
* This is an example that demonstrate the use of the DIGI POT 7 click board.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initialization enables I2C, perform a hardware reset, enable write and set to normal operating mode,
* also write log.
*
* ## Application Task
* In this example we set different resistance values:
* 1.024 kOhm, 2.048 kOhm, 4.096 kOhm and 8.192 kOhm.
* Results are being sent to the Usart Terminal where you can track their changes.
* All data logs write on USB uart changes approximately for every 5 sec.
*
* @author Stefan Ilic
*
*/
#include "board.h"
#include "log.h"
#include "digipot7.h"
static digipot7_t digipot7;
static log_t logger;
void application_init ( void ) {
log_cfg_t log_cfg; /**< Logger config object. */
digipot7_cfg_t digipot7_cfg; /**< Click config object. */
/**
* Logger initialization.
* Default baud rate: 115200
* Default log level: LOG_LEVEL_DEBUG
* @note If USB_UART_RX and USB_UART_TX
* are defined as HAL_PIN_NC, you will
* need to define them manually for log to work.
* See @b LOG_MAP_USB_UART macro definition for detailed explanation.
*/
LOG_MAP_USB_UART( log_cfg );
log_init( &logger, &log_cfg );
log_info( &logger, " Application Init " );
// Click initialization.
digipot7_cfg_setup( &digipot7_cfg );
DIGIPOT7_MAP_MIKROBUS( digipot7_cfg, MIKROBUS_1 );
err_t init_flag = digipot7_init( &digipot7, &digipot7_cfg );
if ( I2C_MASTER_ERROR == init_flag ) {
log_error( &logger, " Application Init Error. " );
log_info( &logger, " Please, run program again... " );
for ( ; ; );
}
log_printf( &logger, "----------------------------\r\n" );
log_printf( &logger, " Hardware Reset \r\n" );
digipot7_hw_reset( &digipot7 );
Delay_ms( 100 );
log_printf( &logger, "----------------------------\r\n" );
log_printf( &logger, " Enable Write \r\n" );
digipot7_enable_write( &digipot7 );
Delay_ms( 100 );
log_printf( &logger, "----------------------------\r\n" );
log_printf( &logger, " Set normal operating mode \r\n" );
digipot7_operating_mode( &digipot7, DIGIPOT7_NORMAL_MODE );
Delay_ms( 100 );
log_printf( &logger, "----------------------------\r\n" );
log_info( &logger, " Application Task " );
log_printf( &logger, "----------------------------\r\n" );
}
void application_task ( void ) {
log_printf( &logger, " Set Resistance: 1.024 kOhm \r\n" );
log_printf( &logger, "----------------------------\r\n" );
digipot7_set_resistance( &digipot7, 1024 );
Delay_ms( 5000 );
log_printf( &logger, " Set Resistance: 2.048 kOhm \r\n" );
log_printf( &logger, "----------------------------\r\n" );
digipot7_set_resistance( &digipot7, 2048 );
Delay_ms( 5000 );
log_printf( &logger, " Set Resistance: 4.096 kOhm \r\n" );
log_printf( &logger, "----------------------------\r\n" );
digipot7_set_resistance( &digipot7, 4096 );
Delay_ms( 5000 );
log_printf( &logger, " Set Resistance: 8.192 kOhm \r\n" );
log_printf( &logger, "----------------------------\r\n" );
digipot7_set_resistance( &digipot7, 8192 );
Delay_ms( 5000 );
}
void main ( void ) {
application_init( );
for ( ; ; ) {
application_task( );
}
}
// ------------------------------------------------------------------------ END
