Smart Mic Click is a compact add-on board that provides wake-on-voice capabilities with secured privacy without compromising performance. This board features the IA611, an “Always-On” voice-wake acoustic processor from Knowles Electronics. The IA611 offers flexibility by supporting the most relevant audio and data interfaces and enables ultra-low-power voice and event detection, including voice UI supporting keywords, voice commands, and acoustic event detection. Its integrated programmable DSP is made available to 3rd party algorithms with 168kB of RAM, enabling unlimited creativity. This Click board™ represents an ideal solution to add a voice-enabled VUI or event detection into IoT products such as home sensors, appliances, lifestyle control devices, and security systems.

Smart Mic Click is supported by a mikroSDK compliant library, which includes functions that simplify software development.

Smart Mic Click as its foundation uses the IA611, a flexible, low-power, and highly integrated voice and audio processor system from Knowles Electronics. The IA611 includes an advanced Knowles audio-optimized DSP sub-system that has been designed to calculate intensive audio-processing algorithms with low power consumption. It also consists of 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 is waiting 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, and when acoustic activity is detected, the IA611 automatically enters into 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 peripheral interface with a control interface and audio interface port. Depending on the desired interface, the user needs to 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 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.

• Interface: I²C, SPI, UART
• Compatibility: mikroBUS™
• Dimensions: 57.15 x 25.4mm
• Input Voltage: 3.3V
• Sensitivity: Min. -38 dBFS, Typ. -37 dBFS, Max. -36 dBFS
• Signal to Noise Ratio: -65.5 dB
• Bandwidth: 50 kHz
• Operating Temperature Range: Min. -10°C, Typ. +25°C, Max. +50°C

• Schematic
• IA611 Datasheet
• mikroSDK
• GitHub