Beginner
10 min
0

Provide reliable and precise control over the voltage output with RK1191110001 and STM32F215RE

Ensure that even the slightest trims are accurately digitized and reflected in the voltage output

POT 3 Click with Fusion for STM32 v8

Published Oct 10, 2023

Click board™

POT 3 Click

Development board

Fusion for STM32 v8

Compiler

NECTO Studio

MCU

STM32F215RE

Translate physical POT adjustments into precise voltage reference outputs suitable for sensitive projects in industrial and hobbyist settings, where ease of use and reliability are paramount

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Hardware Overview

How does it work?

POT 3 Click is based on the MCP1501, a precision voltage reference IC from Microchip is used to provide the voltage of 2.048V. This voltage is routed to the small SMD jumper labeled as VREF SEL. By moving the jumper to the 2V position, 2.048V will be applied to one end of the potentiometer. Otherwise, the potentiometer will be connected to the 3.3V rail of the mikroBUS™. The other end of the potentiometer is tied to GND, allowing to select voltage from 0V to VREF (from 0 to 2.048V or from 0 to 3.3V ranges). The adjustable voltage is available on both AN pin of the mikroBUS™ and to the + input pin of the MCP3201. The potentiometer itself is labeled as RK1191110001. It is a high-quality potentiometer from Alps Alpine. This company is otherwise known for their high-quality electromechanical

components, used in many industries. The potentiometer has a carbon-based resistive surface with the resistance of 10 kΩ. It is a single-turn linear potentiometer, with 50% of resistance achieved when in the middle position. Its turning knob is not fixed: the potentiometer has 15mm shaft and a turning knob with the matching shape is delivered in the package with the Click board™. The output of the potentiometer is fed to the non-inverting input of the OPA344, a rail-to-rail single supply operational amplifier, from Texas Instruments. This operational amplifier is a perfect choice for this design, as it allows rail-to-rail operation, uses a single power supply of 5V, and has a stable unity gain. The OPA344 is used as a buffer, providing a constant input and output impedance. Without buffer, variable impedance

would affect the reference voltage. The reference voltage IC can provide less than 10 mA, with the significant voltage drop for output currents exceeding 2 mA. Therefore, the OPA344 ensures good stability of the circuit. The second section of this click board™ consists of the MCP3201 IC, a well known 12-bit ADC from Microchip. The potentiometer end terminals are connected between GND and the VREF, while the buffered voltage from the wiper is connected to the IN+ pin of the MCP3201. VREF is also connected to the reference voltage input pin of the MCP3201. That way, the whole range of the ADC is always used, regardless the chosen VREF voltage. The MCP3201 has its SPI lines routed to the mikroBUS™ so that the values can be read easily by the MCU.

POT 3 Click hardware overview image

Features overview

Development board

Fusion for STM32 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 STMicroelectronics, regardless of their number of pins, and a broad set of unique functions, such as the first-ever embedded debugger/programmer over WiFi. 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 STM32 v8 provides a fluid and immersive working experience, allowing

access anywhere and under any circumstances at any time. Each part of the Fusion for STM32 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 STM32 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.

Fusion for STM32 v8 horizontal image

Microcontroller Overview

MCU Card / MCU

default

Type

8th Generation

Architecture

ARM Cortex-M3

MCU Memory (KB)

512

Silicon Vendor

STMicroelectronics

Pin count

64

RAM (Bytes)

131072

Used MCU Pins

mikroBUS™ mapper

Analog Output
PB0
AN
NC
NC
RST
SPI Chip Select
PA4
CS
SPI Clock
PA5
SCK
SPI Data OUT
PA6
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
NC
NC
INT
NC
NC
TX
NC
NC
RX
NC
NC
SCL
NC
NC
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Schematic

POT 3 Click Schematic schematic

Step by step

Project assembly

Fusion for PIC v8 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Fusion for STM32 v8 as your development board.

Fusion for PIC v8 front image hardware assembly
GNSS2 Click front image hardware assembly
SiBRAIN for PIC32MZ1024EFK144 front image hardware assembly
GNSS2 Click complete accessories setup image hardware assembly
v8 SiBRAIN Access MB 1 - upright/background hardware assembly
Necto image step 2 hardware assembly
Necto image step 3 hardware assembly
Necto image step 4 hardware assembly
NECTO Compiler Selection Step Image hardware assembly
NECTO Output Selection Step Image hardware assembly
Necto image step 6 hardware assembly
Necto image step 7 hardware assembly
Necto image step 8 hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Necto PreFlash Image hardware assembly

Track your results in real time

Application Output

After pressing the "FLASH" button on the left-side panel, it is necessary to open the UART terminal to display the achieved results. By clicking on the Tools icon in the right-hand panel, multiple different functions are displayed, among which is the UART Terminal. Click on the offered "UART Terminal" icon.

UART Application Output Step 1

Once the UART terminal is opened, the window takes on a new form. At the top of the tab are two buttons, one for adjusting the parameters of the UART terminal and the other for connecting the UART terminal. The tab's lower part is reserved for displaying the achieved results. Before connecting, the terminal has a Disconnected status, indicating that the terminal is not yet active. Before connecting, it is necessary to check the set parameters of the UART terminal. Click on the "OPTIONS" button.

UART Application Output Step 2

In the newly opened UART Terminal Options field, we check if the terminal settings are correct, such as the set port and the Baud rate of UART communication. If the data is not displayed properly, it is possible that the Baud rate value is not set correctly and needs to be adjusted to 115200. If all the parameters are set correctly, click on "CONFIGURE".

UART Application Output Step 3

The next step is to click on the "CONNECT" button, after which the terminal status changes from Disconnected to Connected in green, and the data is displayed in the Received data field.

UART Application Output Step 4

Software Support

Library Description

This library contains API for POT 3 Click driver.

Key functions:

  • pot3_read_adc - This function reads the result of AD conversion

  • pot3_read_avg_adc - This function reads the averaged result of AD conversions

  • pot3_get_vout - This function returns VOUT value calculated to millivolts

Open Source

Code example

This example can be found in NECTO Studio. Feel free to download the code, or you can copy the code below.

/*!
 * \file 
 * \brief Pot3 Click example
 * 
 * # Description
 * This application reads voltage value, calculates it to millivolts and then 
 * logs it to the uart terminal.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initializes devices module.
 * 
 * ## Application Task  
 * Reads VOUT value calculated to millivolts with 2000 conversions
 * included in one measurement cycle.
 * 
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "pot3.h"

// ------------------------------------------------------------------ VARIABLES

static pot3_t pot3;
static log_t logger;

static uint16_t voltage_mv;
static uint16_t voltage_old;

// ------------------------------------------------------ APPLICATION FUNCTIONS

void application_init ( void )
{
    log_cfg_t log_cfg;
    pot3_cfg_t pot3_cfg;

    /** 
     * 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.

    pot3_cfg_setup( &pot3_cfg );
    POT3_MAP_MIKROBUS( pot3_cfg, MIKROBUS_1 );
    pot3_init( &pot3, &pot3_cfg );

	voltage_old = 0;
}

void application_task ( void )
{
	voltage_mv = pot3_get_vout( &pot3, POT3_VREF_2V, 2000);
	
	if (voltage_mv != voltage_old)
	{
		log_printf(&logger, " VOUT : %d mV\r\n", voltage_mv);
	}

	voltage_old = voltage_mv;
}

void main ( void )
{
    application_init( );

    for ( ; ; )
    {
        application_task( );
    }
}

// ------------------------------------------------------------------------ END

Additional Support

Resources