Reduce the input voltage to a desired output level with MAXM38643 and PIC18F2682
NanoPower buck solution with industry’s lowest IQ
Published Sep 12, 2024
Click board™
Buck 18 Click
Dev. board
EasyPIC v8
Compiler
NECTO Studio
MCU
PIC18F2682
Keep systems running longer by optimizing power efficiency in portable and battery-powered devices with precise voltage regulation
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Hardware Overview
How does it work?
Buck 18 Click is based on the MAXM38643, an ultra-low-IQ (330nA) buck module from Analog Devices. This module efficiently steps down input voltages from 1.8V to 5.5V (supplied via the VEXT terminal) to output voltages between 0.7V and 3.3V on the VOUT terminal. Additionally, the output voltage is accessible through the analog AN pin on the mikroBUS™ socket. Users can manually adjust the output voltage using the onboard TRIM trimmer or digitally via the AD5171 digital potentiometer controlled through the I2C interface. The adjustment method is selected by positioning the RSEL jumper to either DIGI or TRIM. The AD5171 also allows setting its I2C address using the ADDR SEL jumper. This module is designed for optimal performance, automatically switching between ultra-low-power mode (ULPM), low-power mode
(LPM), and high-power mode (HPM) based on the load current, ensuring efficiency and a quick transient response. In ULPM, the module overregulates to enhance efficiency and allows the output capacitor to manage transient load currents up to 600mA. It is particularly well-suited for portable devices, wearables, hearables, ultra-low-power IoT applications, single Li+ and coin cell battery devices, and more. Besides the I2C interface pins, the board also uses the EN pin for control, which functions as the device enable. Setting this pin to a HIGH logic level enables the buck module while setting it to LOW disables the part and puts it into Shutdown mode. Buck 18 Click also offers versatile power sourcing options, allowing users to choose between internal and external supplies to best suit their application
needs. This flexibility is achieved through the VIN SEL jumper, which enables users to select the VCC position for sourcing power internally via the mikroBUS™ power rails or the VEXT position to connect an external power supply. As mentioned, the external power supply can range from 1.8V to 5.5V, providing a broad voltage range for various project requirements. 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
EasyPIC v8 is a development board specially designed for the needs of rapid development of embedded applications. It supports many high pin count 8-bit PIC microcontrollers from Microchip, regardless of their number of pins, and a broad set of unique functions, such as the first-ever embedded debugger/programmer. 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, EasyPIC v8 provides a fluid and immersive working experience, allowing access anywhere and under any
circumstances at any time. Each part of the EasyPIC v8 development board contains the components necessary for the most efficient operation of the same board. In addition to the advanced integrated CODEGRIP programmer/debugger module, which offers many valuable programming/debugging options and seamless integration with the Mikroe software environment, the board 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 DEVICE, and CAN are also included, including the well-established mikroBUS™ standard, two display options (graphical and character-based LCD), and several different DIP sockets. These sockets cover a wide range of 8-bit PIC MCUs, from the smallest PIC MCU devices with only eight up to forty pins. EasyPIC 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
Architecture
PIC
MCU Memory (KB)
80
Silicon Vendor
Microchip
Pin count
28
RAM (Bytes)
3328
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 EasyPIC 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 Buck 18 Click driver.
Key functions:
buck18_set_vout- This function sets the voltage output level.buck18_read_voltage- This function reads raw ADC value and converts it to proportional voltage level.buck18_enable- This function turns on the power switch and enables the buck mode.
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 Buck 18 Click Example.
*
* # Description
* This example demonstrates the use of the Buck 18 Click board by changing the output voltage.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initialization of I2C module and log UART.
* After driver initialization, the app executes a default configuration.
*
* ## Application Task
* The demo application changes the output voltage and displays the current voltage output value.
* Results are being sent to the UART Terminal, where you can track their changes.
*
* @author Nenad Filipovic
*
*/
#include "board.h"
#include "log.h"
#include "buck18.h"
static buck18_t buck18; /**< Buck 18 Click driver object. */
static log_t logger; /**< Logger object. */
void application_init ( void )
{
log_cfg_t log_cfg; /**< Logger config object. */
buck18_cfg_t buck18_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.
buck18_cfg_setup( &buck18_cfg );
BUCK18_MAP_MIKROBUS( buck18_cfg, MIKROBUS_1 );
err_t init_flag = buck18_init( &buck18, &buck18_cfg );
if ( ( ADC_ERROR == init_flag ) || ( I2C_MASTER_ERROR == init_flag ) )
{
log_error( &logger, " Communication init." );
for ( ; ; );
}
if ( BUCK18_ERROR == buck18_default_cfg ( &buck18 ) )
{
log_error( &logger, " Default configuration." );
for ( ; ; );
}
log_info( &logger, " Application Task " );
}
void application_task ( void )
{
for ( buck18_vout_t vout = BUCK18_VOUT_3V3; vout <= BUCK18_VOUT_0V9; vout++ )
{
if ( BUCK18_OK == buck18_set_vout( &buck18, vout ) )
{
float voltage = 0;
if ( BUCK18_OK == buck18_read_voltage( &buck18, &voltage ) )
{
log_printf( &logger, " Voltage : %.3f[V]\r\n\n", voltage );
Delay_ms( 5000 );
}
}
}
}
int main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
return 0;
}
// ------------------------------------------------------------------------ END
