Broadcast the music via the FM radio band using the Si4713-B30 and STM32L073RZ
Superior performance in FM broadcasting covering a frequency range from 76MHz to 108MHz
Published Feb 26, 2024
Click board™
RadioStation Click
Dev Board
Nucleo-64 with STM32L073RZ MCU
Compiler
NECTO Studio
MCU
STM32L073RZ
Combined with the capability to broadcast both music and informational data, this project is a match for anyone looking to explore the world of FM broadcasting or to develop applications requiring FM signal transmission
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Hardware Overview
How does it work?
RadioStation Click is based on the Si4713-B30, an FM radio transmitter with receive power scan from Silicon Labs. The RadioStation Click broadcasts the audio signal by utilizing the principles of FM radio broadcasting. The audio signal, brought to the low noise analog input terminals of the Si4713-B30 routed to a mini 3.5 female jack on board, is attenuated and converted into an alias-free, digital format. The digitalized audio is then sent to the digital signal processor (DSP) section of the Si4713-B30 IC, which provides modulation adjustment and audio dynamic range control of the signal for the best listening experience. The audio signal is processed to have the optimal dynamic qualities. Also, Si4713 has programmable low audio and high audio-level indicators that enable and
disable the carrier signal based on the presence of audio content. The Si4713-B30 IC can be used to measure the received signal. The antenna which is used to broadcast the signal can also be used to accept the incoming signal sent by the receiving device. Although it can be used both to receive and transmit signals, the antenna can't operate in both modes simultaneously. This feature can be useful when calibrating the transmission power of the Click board™. The Si4713-B30 integrates the complete transmit functions for standards-compliant unlicensed FM broadcast stereo transmission. The user application must comply with the local radio frequency (RF) transmission regulations. RadioStation Click uses a standard 2-Wire I2C interface to communicate with the host
MCU, supporting clock frequency of up to 400KHz. The I2C address can be selected over the SEN pin of the mikroBUS™ socket, depending on the logic state. The radio transmitter can be reset over the RST pin, which will, among others, disable analog and digital circuitry. The device will interrupt the host MCU over the INT pin if a condition occurs, such as the frequency exceeding the deviation level. 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. However, the Click board™ 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
Nucleo-64 with STM32L073RZ 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-M0
MCU Memory (KB)
192
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.
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Schematic
Step by step
Project assembly
Start by selecting your development board and Click board™. Begin with the Nucleo-64 with STM32L073RZ 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 RadioStation Click driver.
Key functions:
radiostation_get_asq_status- This function returns status information about the audio signal quality and current FM transmit frequencyradiostation_power_up- This function powers up the chip with default settingsradiostation_get_tune_status- This function returns status information which is set by radiostation_get_tune_measure, radiostation_set_tune_frequency or radiostation_set_tune_power
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 RadioStation Click example
*
* # Description
* RadioStation click can be used to broadcast the music via the FM radio band
* ( which operates in the frequency range of 76MHz to 108MHz ).
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initialization driver enable's - I2C and sets transmit_frequency.
*
* ## Application Task
* In this example Radio Station Click is receiving signal from audio connector and broadcasting
* it on 100.00 MHz frequency.
*
*
* \author MikroE Team
*
*/
// ------------------------------------------------------------------- INCLUDES
#include "board.h"
#include "log.h"
#include "radiostation.h"
// ------------------------------------------------------------------ VARIABLES
static radiostation_t radiostation;
static radiostation_cmd_t radiostation_cmd;
static log_t logger;
static uint8_t buff[ 16 ];
// ------------------------------------------------------ APPLICATION FUNCTIONS
void application_init ( void )
{
log_cfg_t log_cfg;
radiostation_cfg_t 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.
radiostation_cfg_setup( &cfg, true );
RADIOSTATION_MAP_MIKROBUS( cfg, MIKROBUS_1 );
radiostation_init( &radiostation, &cfg );
radiostation.transmit_frequency = 10000;
radiostation.status = 0xFF;
radiostation_default_cfg( &radiostation, &radiostation_cmd );
}
void application_task ( void )
{
radiostation_get_asq_status( &radiostation, &radiostation_cmd, &buff[ 0 ] );
Delay_ms( 50 );
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END
