Enrich every note and deliver an unparalleled auditory journey using MAX9723 and STM32F103RB
Turn up the quality, not just the volume!
Published Oct 08, 2024
Click board™
Headphone AMP 2 Click
Dev Board
Nucleo 64 with STM32F103RB MCU
Compiler
NECTO Studio
MCU
STM32F103RB
Our headphone amplifier is the ultimate companion for those who demand exceptional audio quality.
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Hardware Overview
How does it work?
Headphone AMP 2 Click is based on the MAX9723, a stereo DirectDrive headphone amplifier with BassMax, volume control, and I2C from Analog Devices. The headphone amplifier uses a DirectDrive architecture that produces a ground-referenced output from a single supply, thus eliminating the need for large DC-blocking capacitors. Its outputs are biased at 0V, making the amplifier outputs not have a DC component, improving a low-frequency response. The DirectDrive architecture uses a charge pump to create an internal negative supply voltage, which makes the dynamic range from a single supply almost double. Software-enabled bass boost (BassMax) boosts the bass response of the
amplifier, improving audio reproduction when using inexpensive headphones. This, in particular, comes in handy when reproducing low frequencies, where the limitations of the small physical size of the diaphragm are compensated by increasing the amplifier gain. The maximum amplifier gain on this chip is +6dB. The volume control adjusts the gain of the output amplifiers according to your needs over the software. The amplifier can enter the low-power shutdown mode, where the host MCU controls the shutdown mode. Headphone AMP 2 Click uses a standard 2-Wire I2C interface to communicate with the host MCU, supporting clock rates of up to 400kHz. The shutdown control is available on the SHD pin of
the mikroBUS™ socket. In addition to the 3.5mm input and output audio jacks, there are corresponding two channels input and output headers in case of the need to connect inputs or outputs incompatible with jack connectors (wire types). 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, 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
Nucleo-64 with STM32F103RB MCU offers a cost-effective and adaptable platform for developers to explore new ideas and prototype their designs. This board harnesses the versatility of the STM32 microcontroller, enabling users to select the optimal balance of performance and power consumption for their projects. It accommodates the STM32 microcontroller in the LQFP64 package and includes essential components such as a user LED, which doubles as an ARDUINO® signal, alongside user and reset push-buttons, and a 32.768kHz crystal oscillator for precise timing operations. Designed with expansion and flexibility in mind, the Nucleo-64 board features an ARDUINO® Uno V3 expansion connector and ST morpho extension pin
headers, granting complete access to the STM32's I/Os for comprehensive project integration. Power supply options are adaptable, supporting ST-LINK USB VBUS or external power sources, ensuring adaptability in various development environments. The board also has an on-board ST-LINK debugger/programmer with USB re-enumeration capability, simplifying the programming and debugging process. Moreover, the board is designed to simplify advanced development with its external SMPS for efficient Vcore logic supply, support for USB Device full speed or USB SNK/UFP full speed, and built-in cryptographic features, enhancing both the power efficiency and security of projects. Additional connectivity is
provided through dedicated connectors for external SMPS experimentation, a USB connector for the ST-LINK, and a MIPI® debug connector, expanding the possibilities for hardware interfacing and experimentation. Developers will find extensive support through comprehensive free software libraries and examples, courtesy of the STM32Cube MCU Package. This, combined with compatibility with a wide array of Integrated Development Environments (IDEs), including IAR Embedded Workbench®, MDK-ARM, and STM32CubeIDE, ensures a smooth and efficient development experience, allowing users to fully leverage the capabilities of the Nucleo-64 board in their projects.
Microcontroller Overview
MCU Card / MCU
Architecture
ARM Cortex-M3
MCU Memory (KB)
128
Silicon Vendor
STMicroelectronics
Pin count
64
RAM (Bytes)
20480
You complete me!
Accessories
Click Shield for Nucleo-64 comes equipped with two proprietary mikroBUS™ sockets, allowing all the Click board™ devices to be interfaced with the STM32 Nucleo-64 board with no effort. This way, Mikroe allows its users to add any functionality from our ever-growing range of Click boards™, such as WiFi, GSM, GPS, Bluetooth, ZigBee, environmental sensors, LEDs, speech recognition, motor control, movement sensors, and many more. More than 1537 Click boards™, which can be stacked and integrated, are at your disposal. The STM32 Nucleo-64 boards are based on the microcontrollers in 64-pin packages, a 32-bit MCU with an ARM Cortex M4 processor operating at 84MHz, 512Kb Flash, and 96KB SRAM, divided into two regions where the top section represents the ST-Link/V2 debugger and programmer while the bottom section of the board is an actual development board. These boards are controlled and powered conveniently through a USB connection to program and efficiently debug the Nucleo-64 board out of the box, with an additional USB cable connected to the USB mini port on the board. Most of the STM32 microcontroller pins are brought to the IO pins on the left and right edge of the board, which are then connected to two existing mikroBUS™ sockets. This Click Shield also has several switches that perform functions such as selecting the logic levels of analog signals on mikroBUS™ sockets and selecting logic voltage levels of the mikroBUS™ sockets themselves. Besides, the user is offered the possibility of using any Click board™ with the help of existing bidirectional level-shifting voltage translators, regardless of whether the Click board™ operates at a 3.3V or 5V logic voltage level. Once you connect the STM32 Nucleo-64 board with our Click Shield for Nucleo-64, you can access hundreds of Click boards™, working with 3.3V or 5V logic voltage levels.
These standard small stereo earphones offer a high-quality listening experience with their top-notch stereo cable and connector. Designed for universal compatibility, they effortlessly connect to all MIKROE mikromedia and multimedia boards, making them an ideal choice for your electronic projects. With a rated power of 100mW, the earphones provide crisp audio across a broad frequency range from 20Hz to 20kHz. They boast a sensitivity of 100 ± 5dB and an impedance of 32Ω ± 15%, ensuring optimal sound quality. The Φ15mm speaker delivers clear and immersive audio. Cost-effective and versatile, these earphones are perfect for testing your prototype devices, offering an affordable and reliable audio solution to complement your projects.
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 Nucleo 64 with STM32F103RB MCU as your development board.
Track your results in real time
Application Output via Debug Mode
1. Once the code example is loaded, pressing the "DEBUG" button initiates the build process, programs it on the created setup, and enters Debug mode.
2. After the programming is completed, a header with buttons for various actions within the IDE becomes visible. Clicking the green "PLAY" button starts reading the results achieved with the Click board™. The achieved results are displayed in the Application Output tab.
Software Support
Library Description
This library contains API for Headphone AMP 2 Click driver.
Key functions:
headphoneamp2_set_command- Headphone AMP 2 set the command function.headphoneamp2_enable- Headphone AMP 2 enable the device function.headphoneamp2_disable- Headphone AMP 2 disable the device function.
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 Headphone AMP 2 Click example
*
* # Description
* This example demonstrates the use of the Headphone AMP 2 Click board™,
* the headphone amplifier with BassMax and volume control.
*
* The demo application is composed of two sections :
*
* ## Application Init
* The initialization of I2C module and log UART.
* After driver initialization, the app sets the default configuration.
*
* ## Application Task
* This example demonstrates the use of the Headphone AMP 2 Click board™.
* The application wakes up the device, enables BassMax and Maximum Gain modes,
* and switches the sound volume from level 1 to the max level.
* Results are being sent to the UART Terminal, where you can track their changes.
*
* @author Nenad Filipovic
*
*/
#include "board.h"
#include "log.h"
#include "headphoneamp2.h"
static headphoneamp2_t headphoneamp2;
static log_t logger;
void application_init ( void )
{
log_cfg_t log_cfg; /**< Logger config object. */
headphoneamp2_cfg_t headphoneamp2_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.
headphoneamp2_cfg_setup( &headphoneamp2_cfg );
HEADPHONEAMP2_MAP_MIKROBUS( headphoneamp2_cfg, MIKROBUS_1 );
if ( I2C_MASTER_ERROR == headphoneamp2_init( &headphoneamp2, &headphoneamp2_cfg ) )
{
log_error( &logger, " Communication init." );
for ( ; ; );
}
if ( HEADPHONEAMP2_ERROR == headphoneamp2_default_cfg ( &headphoneamp2 ) )
{
log_error( &logger, " Default configuration." );
for ( ; ; );
}
log_info( &logger, " Application Task " );
log_printf( &logger, "-------------------------\r\n" );
Delay_ms( 100 );
}
void application_task ( void )
{
static headphoneamp2_cmd_t cmd_ctrl;
cmd_ctrl.wakes_up = HEADPHONEAMP2_CMD_ENABLE;
cmd_ctrl.bass_max = HEADPHONEAMP2_CMD_ENABLE;
cmd_ctrl.gain_max = HEADPHONEAMP2_CMD_ENABLE;
cmd_ctrl.volume = HEADPHONEAMP2_VOL_MUTE;
log_printf( &logger, " Volume : " );
for ( uint8_t volume = HEADPHONEAMP2_VOL_LVL_1; volume <= HEADPHONEAMP2_VOL_LVL_MAX; volume++ )
{
cmd_ctrl.volume = volume;
if ( HEADPHONEAMP2_OK == headphoneamp2_set_command( &headphoneamp2, cmd_ctrl ) )
{
log_printf( &logger, "|" );
}
Delay_ms( 1000 );
}
log_printf( &logger, "\r\n-------------------------\r\n" );
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END
