Create a custom voice-activated system with IA611 and STM32L496AG
Say it, and it shall be done!
Published Jul 22, 2025
Click board™
Smart Mic Click
Dev. board
Discovery kit with STM32L496AG MCU
Compiler
NECTO Studio
MCU
STM32L496AG
Identify a particular spoken keyword or trigger phrase within a larger sentence or command to wake up any embedded system
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Hardware Overview
How does it work?
Smart Mic Click is based on the IA611, a flexible, low-power, highly integrated voice and audio processor system from Knowles Electronics. The IA611 includes an advanced Knowles audio-optimized DSP sub-system designed to calculate intensive audio-processing algorithms with low power consumption. It also comprises a System Control Unit (SCU) that handles power management states such as sleep mode and generates internal clock signals. The IA611, “Always-On” Acoustic Processor, features a voice wake and voice ID keyword detector, a three-second buffer, and Knowles’ proven high-performance acoustic SiSonicTM MEMS technology in a single package. The IA611 can be in one of the following operating modes. The Bootloader is a mode where, after Power-Up, the IA611 waits for firmware download or use case setup. In Instruction mode, the IA611 waits for use case setup after firmware download, while in Open DSP Mode, the IA611 enables third-party algorithms. In Normal operational mode, the IA611 can be in software or hardware pass-through mode, which acts as a mic to the host.
The Voice Wake Mode allows low-power voice wake-up based on the detection of either a built-in keyword (OEM keyword), a user-trained keyword (user keyword), or a user-conditioned OEM keyword (Voice ID). In this mode, the IA611 monitors the microphone stream for acoustic activity. When acoustic activity is detected, the IA611 automatically enters a slightly higher power mode to analyze the speech utterance for the presence of the wake-up keyword. When a valid keyword is detected, the IA611 asserts an interrupt routed to the INT pin of the mikroBUS™ socket to trigger a complete system wake-up. If a keyword is not detected, the device returns to the ultra-low-power mode until the acoustic activity is detected again. The IA611 implements various control interfaces, including UART, SPI, and an I2C slave interface with a control interface and audio interface port. Depending on the desired interface, the user must populate the selected jumper to activate that interface (SPI, I2C, or UART). Using an I2C interface, the user is given the option of additional activation of 4.7kΩ pull-up resistors on I2C lines,
populating jumpers marked with PULL-UP. The IA611 does not require a specific Power-Up sequence but requires a voltage of 1.8V for its supply and logic part to work correctly. Therefore, a small regulating LDO is used, the TC1015, providing a 1.8V out of 3.3V mikroBUS™ power rail, alongside Enable feature through the EN pin routed to the RST pin of the mikroBUS™ socket offering a switch operation to turn ON/OFF power delivery to the TC1015. Since the sensor for operation requires a power supply of 1.8V, this Click board™ also features the TXS0108E voltage-level translator. The interface lines are routed to the voltage-level translator allowing this Click board™ to work with 3.3V MCUs properly. This Click board™ can only be operated 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
The 32L496GDISCOVERY Discovery kit serves as a comprehensive demonstration and development platform for the STM32L496AG microcontroller, featuring an Arm® Cortex®-M4 core. Designed for applications that demand a balance of high performance, advanced graphics, and ultra-low power consumption, this kit enables seamless prototyping for a wide range of embedded solutions. With its innovative energy-efficient
architecture, the STM32L496AG integrates extended RAM and the Chrom-ART Accelerator, enhancing graphics performance while maintaining low power consumption. This makes the kit particularly well-suited for applications involving audio processing, graphical user interfaces, and real-time data acquisition, where energy efficiency is a key requirement. For ease of development, the board includes an onboard ST-LINK/V2-1
debugger/programmer, providing a seamless out-of-the-box experience for loading, debugging, and testing applications without requiring additional hardware. The combination of low power features, enhanced memory capabilities, and built-in debugging tools makes the 32L496GDISCOVERY kit an ideal choice for prototyping advanced embedded systems with state-of-the-art energy efficiency.
Microcontroller Overview
MCU Card / MCU
Architecture
ARM Cortex-M4
MCU Memory (KB)
1024
Silicon Vendor
STMicroelectronics
Pin count
169
RAM (Bytes)
327680
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 Discovery kit with STM32L496AG MCU as your development board.
Software Support
Library Description
This library contains API for Smart Mic Click driver.
Key functions:
smartmic_wait_keywordThis function waits for a keyword event, reads it, and returns the keyword ID number.smartmic_download_keywordThis function downloads keyword models to the module.smartmic_voice_makeThis function performs the voice-make feature. It stops the route, then sets the digital gain to 20db, sample rate to 16K, frame size to 16 ms, and finally, it selects route 6 and configures algorithm parameters.
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 SmartMic Click example
*
* # Description
* This example demonstrates the use of Smart Mic Click board by programming
* it with 4 different keywords, and then waiting for a keyword event,
* parsing it and displaying on the USB UART.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes the driver and performs the Click default configuration
* which programs the device with system config, firmware, and 4 keywords
* ("Hello VoiceQ","Switch The Light","Next Song","Baidu Yixia") binaries.
*
* ## Application Task
* Waits for a keyword event, parses it and displays on the USB UART
* an appropriate message for the detected keyword.
*
* @author Stefan Filipovic
*
*/
#include "board.h"
#include "log.h"
#include "smartmic.h"
static smartmic_t smartmic;
static log_t logger;
void application_init ( void )
{
log_cfg_t log_cfg; /**< Logger config object. */
smartmic_cfg_t smartmic_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.
smartmic_cfg_setup( &smartmic_cfg );
SMARTMIC_MAP_MIKROBUS( smartmic_cfg, MIKROBUS_1 );
if ( SMARTMIC_OK != smartmic_init( &smartmic, &smartmic_cfg ) )
{
log_error( &logger, " Communication init." );
for ( ; ; );
}
log_printf( &logger, " Configuring device... \r\n" );
if ( SMARTMIC_OK != smartmic_default_cfg ( &smartmic ) )
{
log_error( &logger, " Default configuration." );
for ( ; ; );
}
log_info( &logger, " Application Task " );
}
void application_task ( void )
{
switch ( smartmic_wait_keyword ( &smartmic ) )
{
case SMARTMIC_OEM1_KWD_DETECTED:
{
log_printf ( &logger, " Hello VoiceQ keyword detected!\r\n" );
break;
}
case SMARTMIC_OEM2_KWD_DETECTED:
{
log_printf ( &logger, " Switch The Light keyword detected!\r\n" );
break;
}
case SMARTMIC_OEM3_KWD_DETECTED:
{
log_printf ( &logger, " Next Song keyword detected!\r\n" );
break;
}
case SMARTMIC_OEM4_KWD_DETECTED:
{
log_printf ( &logger, " Baidu YiXia keyword detected!\r\n" );
break;
}
}
}
int main ( void )
{
/* Do not remove this line or clock might not be set correctly. */
#ifdef PREINIT_SUPPORTED
preinit();
#endif
application_init( );
for ( ; ; )
{
application_task( );
}
return 0;
}
// ------------------------------------------------------------------------ END
Additional Support
Resources
Category:Microphone
