30 min

Charge smarter not harder with the help of MCP73123 and PIC18LF4680

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Charger 11 Click with EasyPIC v7

Published Nov 01, 2023

Click board™

Charger 11 Click


EasyPIC v7


NECTO Studio



Fast, safe, and reliable charging that never lets you down



Hardware Overview

How does it work?

Charger 11 Click is based on the MCP73123, a highly integrated Lithium Iron Phosphate (LiFePO4) battery charge management controller for use in space-limited and cost-sensitive applications from Microchip. The MCP73123 is an efficient Lithium Iron Phosphate battery charger, thanks to specific charge algorithms for LiFePO4 batteries to achieve optimal capacity and safety in the shortest charging time possible. Besides its small physical size, the low number of external components makes this IC ideal for various applications. MCP73123 is designed to employ a constant current and constant voltage charge algorithm. The 3.6V factory preset reference voltage simplifies design. A digital potentiometer, the MCP4161, sets the fast charge constant current with an external 1K resistor in series. The MCP73123 also limits the charge current based on the temperature during high power or ambient conditions. This thermal regulation optimizes the charge cycle time while maintaining device reliability. PROG pin of the MCP73123 also serves as the enable pin, where on this Click, it is wired in rheostat configuration

with the digital potentiometer - that way, the charging current can be controlled. The digital potentiometer on Charger 11 click is MCP4161 which offers a wide range of product offerings using an SPI interface. WiperLock technology allows application-specific calibration settings to be secured in EEPROM. This digital pot is tied with a charger IC over its P0A control pin. Battery charging can be controlled by assigning values on MCP4161 from 0 to 10 kiloohms. As there is a 1 K resistor in series, it can never be 0 ohms on the MCP73123 charger's PROG pin. However, maximum resistance cannot exceed 11 kiloohms. Fast charging can be regulated with 10K on the PROG pin to get 130 mA. To get 1000 mA digital potentiometer needs to go down to 0,1 K, along with an external resistor, which makes 1,1 K. Communication with a digital potentiometer on this Click, and controlling the charger is done through the SPI interface. Another feature of Charger 11 click is battery voltage monitoring, which uses an MCP3221 Analog-To-Digital converter. It is a 12-bit resolution SOT12 package device that provides one

single-ended input based on advanced CMOS technology. Communication to the MCP3221 is done by the I2C interface, where standard and fast modes are available for this device. Charger 11 Click for voltage reference uses an MCP1541, which has a high precision output voltage of 4.096 volts, which is then compared to battery voltage to get precise measurements. This voltage reference circuit uses a combination of an advanced CMOS design and EPROM timing to provide initial tolerance of ±1% max. On the right side of the click board is an input screw terminal with corresponding markings, where the recommended external voltage of 6V can be applied. The left screw terminal is reserved for a Lithium Iron Phosphate battery with GND and VBAT+ markings. The green PWR LED will indicate it when connected to a power source. Red LED1 and green LED2 can be used for visual charge monitoring. These two LEDs are multipurpose and can be used for various things.

Charger 11 Click hardware overview image

Features overview

Development board

EasyPIC v7 is the seventh generation of PIC development boards specially designed to develop embedded applications rapidly. It supports a wide range of 8-bit PIC microcontrollers from Microchip and has a broad set of unique functions, such as a powerful onboard mikroProg programmer and In-Circuit debugger over USB-B. The development board is well organized and designed so that the end-user has all the necessary elements in one place, such as switches, buttons, indicators, connectors, and others. With four different connectors for each port, EasyPIC v7 allows you to connect accessory boards, sensors, and custom electronics more efficiently than ever. Each part of

the EasyPIC v7 development board contains the components necessary for the most efficient operation of the same board. An integrated mikroProg, a fast USB 2.0 programmer with mikroICD hardware In-Circuit Debugger, offers many valuable programming/debugging options and seamless integration with the Mikroe software environment. Besides it also includes a clean and regulated power supply block for the development board. It can use various external power sources, including an external 12V power supply, 7-23V AC or 9-32V DC via DC connector/screw terminals, and a power source via the USB Type-B (USB-B) connector. Communication options such as

USB-UART and RS-232 are also included, alongside the well-established mikroBUS™ standard, three display options (7-segment, graphical, and character-based LCD), and several different DIP sockets. These sockets cover a wide range of 8-bit PIC MCUs, from PIC10F, PIC12F, PIC16F, PIC16Enh, PIC18F, PIC18FJ, and PIC18FK families. EasyPIC v7 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.

EasyPIC v7 horizontal image

Microcontroller Overview

MCU Card / MCU




MCU Memory (KB)


Silicon Vendor


Pin count


RAM (Bytes)


You complete me!


Li-Polymer Battery is the ideal solution for devices that demand a dependable and long-lasting power supply while emphasizing mobility. Its compatibility with mikromedia boards ensures easy integration without additional modifications. With a voltage output of 3.7V, the battery meets the standard requirements of many electronic devices. Additionally, boasting a capacity of 2000mAh, it can store a substantial amount of energy, providing sustained power for extended periods. This feature minimizes the need for frequent recharging or replacement. Overall, the Li-Polymer Battery is a reliable and autonomous power source, ideally suited for devices requiring a stable and enduring energy solution. You can find a more extensive choice of Li-Polymer batteries in our offer.

Charger 11 Click accessories image

Used MCU Pins

mikroBUS™ mapper

Red LED Indicator
SPI Chip Select
SPI Clock
Power Supply
Green LED Indicator
Battery Charge Status
I2C Clock
I2C Data
Power Supply

Take a closer look


Charger 11 Click Schematic schematic

Step by step

Project assembly

EasyPIC v7 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the EasyPIC v7 as your development board.

EasyPIC v7 front image hardware assembly
GNSS2 Click front image hardware assembly
MCU DIP 40 hardware assembly
GNSS2 Click complete accessories setup image hardware assembly
EasyPIC v7 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 DIP image step 7 hardware assembly
EasyPIC PRO v7a Display Selection Necto Step 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 Charger 11 Click driver.

Key functions:

  • charger11_spi_increment_wiper - Incrementing wiper position

  • charger11_spi_decrement_wiper  - Decrementing wiper position

  • charger11_i2c_get_volt - Getting output voltage

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 main.c
 * @brief Charger11 Click example
 * # Description
 * This is an example that demonstrates the use of the Charger 11 Click board.
 * The demo application is composed of two sections :
 * ## Application Init
 * Initalizes INT ( ST ), PWM ( LG ), AN ( LR ) pins and SPI, I2C, LOG modules.
 * ## Application Task
 * Waits for user input in order to increment, decrement wiper or log report 
 * (Wiper position and Output voltage)
 * Additional Functions :
 * - charger11_log_wiper_position( charger11_t *ctx ) - Logs current Wiper position.
 * - charger11_case_plus( charger11_t *ctx ) - Increments Wiper position.
 * - charger11_case_minus( charger11_t *ctx ) - Decrements Wiper position.
 * - charger11_case_report( charger11_t *ctx ) - Logs current Wiper position and Output voltage.
 * @author Stefan Ilic

#include "board.h"
#include "log.h"
#include "charger11.h"

static charger11_t charger11;
static log_t logger;

 * @brief Charger 11 log wiper position.
 * @details This function reads wiper position and logs it on UART terminal.
void charger11_log_wiper_position( charger11_t *ctx );

 * @brief Charger 11 increase wiper position.
 * @details This function increases wiper position and logs it on UART terminal.
void charger11_case_plus( charger11_t *ctx );

 * @brief Charger 11 decrease wiper position.
 * @details This function decreases wiper position and logs it on UART terminal.
void charger11_case_minus( charger11_t *ctx );

 * @brief Charger 11 log wiper position and voltage.
 * @details This function reads wiper position and voltage and logs them on UART terminal.
void charger11_case_report( charger11_t *ctx );

void application_init ( void ) {
    log_cfg_t log_cfg;  /**< Logger config object. */
    charger11_cfg_t charger11_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.
    charger11_cfg_setup( &charger11_cfg );
    CHARGER11_MAP_MIKROBUS( charger11_cfg, MIKROBUS_1 );
    err_t init_flag  = charger11_init( &charger11, &charger11_cfg );
    if ( ( I2C_MASTER_ERROR == init_flag ) || ( SPI_MASTER_ERROR == init_flag ) ) {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );
    log_info( &logger, " Application Task " );
    charger11_case_report( &charger11 );

void application_task ( void ) {
    char uart_char;
    if ( log_read( &logger, &uart_char, 1 ) ) {
        switch (uart_char) {
            case '+' : {
                charger11_case_plus( &charger11 );
            case '-' : {
                charger11_case_minus( &charger11 );
            case 'r' : {
                charger11_case_report( &charger11 );
            default : {
                log_printf( &logger, "> Invalid command \r\n" );

void main ( void ) {
    application_init( );

    for ( ; ; ) {
        application_task( );

void charger11_log_wiper_position( charger11_t *ctx ) {
    float wiper_position;
    uint8_t aux_wiper_position;
    aux_wiper_position = charger11_spi_get_wiper_position( ctx );

    wiper_position = ( float ) aux_wiper_position / 255.0;
    wiper_position *= 100.0;
    log_printf( &logger, "> Wiper position : %.2f %%\r\n", wiper_position );

void charger11_case_plus( charger11_t *ctx ) {
    log_printf( &logger, "> Wiper incremented\r\n" );
    charger11_spi_increment_wiper( ctx );
    charger11_log_wiper_position( ctx );

void charger11_case_minus( charger11_t *ctx ) {
    log_printf( &logger, "> Wiper decremented\r\n" );
    charger11_spi_decrement_wiper( ctx );
    charger11_log_wiper_position( ctx );

void charger11_case_report( charger11_t *ctx ) {
    float volt_data;
    charger11_log_wiper_position( ctx );
    volt_data = charger11_i2c_get_volt( ctx, 4096.0 );
    log_printf( &logger, "> Output voltage : %d mV\r\n", ( uint16_t ) volt_data );

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

Additional Support