Embrace the future of potentiometers with AD5206 and PIC18F2455
Simplify voltage adjustments
Published Jan 23, 2024
Click board™
DIGI POT 8 Click
Dev. board
Curiosity HPC
Compiler
NECTO Studio
MCU
PIC18F2455
From audio equipment to industrial automation, our digital potentiometers offer an electronic means to finely tune parameters, enhancing overall system performance and accuracy
A
A
Hardware Overview
How does it work?
DIGI POT 8 Click is based on the AD5206, 6-channel 256-position digitally controlled device that performs the same electronic adjustment function as a potentiometer or variable resistor from Analog Devices. Each channel of the AD5206 contains a fixed resistor with a wiper contact that taps the fixed resistor value of 100kΩ at a point determined by a digital code loaded into the SPI-compatible serial-input register. The resistance between the wiper and either endpoint of the fixed resistor varies linearly concerning the digital code transferred into the variable resistor (VR) latch. The AD5206 also has an internal Power-On preset that places the wiper in a preset midscale condition at the Power-On state. The AD5206 communicates with MCU through the 3-wire
SPI serial interface with a maximum frequency 10MHz. Each VR has its VR latch that holds its programmed resistance value. These VR latches are updated from an internal serial-to-parallel shift register loaded from a standard 3-wire SPI serial-input digital interface. Eleven bits make up the data word clocked into the serial input register. The first three bits are decoded to determine which VR latch is loaded with the last eight bits of the data word when the CS pin of the SPI serial interface returns to a logic high state. In addition to the AD5206 present on the DIGI POT 8, this Click board™ has four 2x3 male headers. Three of them, under the labels A, W, and B, with the appropriate number, represent the corresponding DIGI POT terminal of the AD5206, while
the fourth header, with the label VCC and GND, represents an additional power supply output. Wiper terminal number 6, labeled as W6, also can be used as an auxiliary wiper output, routed to the AN pin of the mikroBUS ™ socket if the wiper back to the mikroBUS™ is required. This Click board™ can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. Also, it comes equipped with a library containing functions and an example code that can be used, as a reference, for further development.
Features overview
Development board
Curiosity HPC, standing for Curiosity High Pin Count (HPC) development board, supports 28- and 40-pin 8-bit PIC MCUs specially designed by Microchip for the needs of rapid development of embedded applications. This board has two unique PDIP sockets, surrounded by dual-row expansion headers, allowing connectivity to all pins on the populated PIC MCUs. It also contains a powerful onboard PICkit™ (PKOB), eliminating the need for an external programming/debugging tool, two mikroBUS™ sockets for Click board™ connectivity, a USB connector, a set of indicator LEDs, push button switches and a variable potentiometer. All
these features allow you to combine the strength of Microchip and Mikroe and create custom electronic solutions more efficiently than ever. Each part of the Curiosity HPC development board contains the components necessary for the most efficient operation of the same board. An integrated onboard PICkit™ (PKOB) allows low-voltage programming and in-circuit debugging for all supported devices. When used with the MPLAB® X Integrated Development Environment (IDE, version 3.0 or higher) or MPLAB® Xpress IDE, in-circuit debugging allows users to run, modify, and troubleshoot their custom software and hardware
quickly without the need for additional debugging tools. Besides, it includes a clean and regulated power supply block for the development board via the USB Micro-B connector, alongside all communication methods that mikroBUS™ itself supports. Curiosity HPC development board allows you to create a new application in just a few steps. Natively supported by Microchip software tools, it covers many aspects of prototyping thanks to many number of different Click boards™ (over a thousand boards), the number of which is growing daily.
Microcontroller Overview
MCU Card / MCU
Architecture
PIC
MCU Memory (KB)
24
Silicon Vendor
Microchip
Pin count
28
RAM (Bytes)
2048
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 Curiosity HPC 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 8 Click driver.
Key functions:
digipot8_write_data- DIGI POT 8 write data functiondigipot8_set_wiper_1- DIGI POT 8 set wiper 2 functiondigipot8_set_wiper_2- DIGI POT 8 set wiper 3 function
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 DIGIPOT8 Click example
*
* # Description
* This example demonstrates the use of DIGI POT 8 Click board.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes the driver and makes an initial log.
*
* ## Application Task
* Iterates through the entire wiper range and sets all wipers to
* the iterator value each second.
* The current wiper position will be displayed on USB UART.
*
* @author Stefan Filipovic
*
*/
#include "board.h"
#include "log.h"
#include "digipot8.h"
static digipot8_t digipot8;
static log_t logger;
void application_init ( void )
{
log_cfg_t log_cfg; /**< Logger config object. */
digipot8_cfg_t digipot8_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.
digipot8_cfg_setup( &digipot8_cfg );
DIGIPOT8_MAP_MIKROBUS( digipot8_cfg, MIKROBUS_1 );
err_t init_flag = digipot8_init( &digipot8, &digipot8_cfg );
if ( init_flag == SPI_MASTER_ERROR )
{
log_error( &logger, " Application Init Error. " );
log_info( &logger, " Please, run program again... " );
for ( ; ; );
}
log_info( &logger, " Application Task " );
}
void application_task ( void )
{
for ( uint8_t cnt = DIGIPOT8_WIPER_POSITION_MIN; cnt < DIGIPOT8_WIPER_POSITION_MAX; cnt += 5 )
{
digipot8_set_wiper_1 ( &digipot8, cnt );
digipot8_set_wiper_2 ( &digipot8, cnt );
digipot8_set_wiper_3 ( &digipot8, cnt );
digipot8_set_wiper_4 ( &digipot8, cnt );
digipot8_set_wiper_5 ( &digipot8, cnt );
digipot8_set_wiper_6 ( &digipot8, cnt );
log_printf( &logger, " * All wipers position set to %d *\r\n", ( uint16_t ) cnt );
Delay_ms( 1000 );
}
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END
