Event activity detection signal

Abstract

Acoustic and other activity detection signals are provided herein. An operation of a method may include determining that a micro-electro-mechanical system (MEMS) device is no longer in an initialized state and receiving a first signal indicating the MEMS device to perform event activity detection. The method may also include receiving one or more event signals and determining that an event signal of the one or more event signals satisfies the defined event characteristic. The method may also include outputting a second signal including information indicating that the event activity detected at the MEMS device is greater than the defined event characteristic.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. non-provisional patent application serial number: 17 / 821,548, filed on August 23, 2022, entitled “EVENT ACTIVITY DETECTION SIGNALING,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates generally to the field of sensors, including sensor microphones, and more particularly to micro-electromechanical systems that detect acoustic event activity and perform event activity detection signals. Background Art

[0004] Activity detection, such as acoustic activity detection and / or other event activity detection, requires a listening device (e.g., an acoustic sensor) to react to audio wake-up activity, which can require significant power, complex systems, and significant processing time to analyze and quantify the audio content. For example, an acoustic sensor may wake up a processing system based solely on an on / off indication that a sound pressure event has exceeded a defined level. The processing system must be fully powered up and collect, process a set of audio data, and perform further processing to analyze and quantify the audio content. Therefore, there are unique challenges in providing an acoustic sensor that can detect and process audio wake-up activity faster, with lower power consumption, and with less complexity. Summary of the invention

[0005] The subject application relates to an acoustic activity detection signal circuit and / or other types of event activity detection signal circuits for a single microphone sensor and / or multiple microphone sensors and other types of sensors. The subject application also relates to an acoustic activity detection method and / or other types of event activity detection methods for a single microphone sensor and / or multiple microphone sensors and other types of sensors.

[0006] Provided herein is a device comprising a micro-electromechanical system (MEMS) transducer and a circuit for activity detection. The circuit may include a first node configured to send or receive data associated with a clock signal. The circuit may also include a second node configured to operate in a first mode during a power-up phase of the device and to operate in a second mode after the power-up phase of the device is completed. The second node is configured to receive a signal that causes the device to perform activity detection based on activity determination.

[0007] In one example, the clock signal is below a normal operating frequency or has stopped at the first node. In another example, according to some implementations, the circuit may include a third node configured to transmit one or more acoustic signals.

[0008] In some implementations, the second node is configured to receive a signal that causes the device to perform acoustic activity detection. For example, the second node may perform acoustic activity detection based on a determination that a clock signal at the first node has stopped or is operating at a frequency below normal operation.

[0009] According to some implementations, when operating in the second mode, the second node is configured as a communication interface for activity detection. In addition to these implementations, the communication interface includes at least one of a transmit signal or a receive signal associated with acoustic activity detection. In some implementations, the communication interface is a single-line communication interface or operates as a single-line communication interface. The communication interface can facilitate write access and read access to internal registers associated with the MEMS transducer. It should be understood by those skilled in the art that writing to the internal register may include changing the functional mode of operation. According to some implementations, the communication interface is a serial interface.

[0010] In one example, the MEMS transducer includes a MEMS acoustic sensor that receives an acoustic signal including an acoustic signal frequency. According to another example, the second node is a MEMS transducer selector pin. According to some implementations, the device may include a serial interface for communicating with an external device. In addition, according to some embodiments, a voltage at the second node indicates a position of the device in the device system.

[0011] According to some embodiments, the activity detection is based on acoustic activity. The acoustic activity may include at least one of speech, keywords, collisions, explosions, gunshots, breaking glass, unsafe sound levels, built-in self-test failures, over temperature thresholds, and under temperature thresholds.

[0012] According to some implementations, the signal is a first received signal. In addition to these embodiments, the device also includes a light sensor. In addition, when operating in the second mode, the second node is configured to send a transmit signal when a second signal from the light sensor exceeds a threshold.

[0013] In some embodiments, the signal is a first receive signal and the device further comprises a humidity sensor.In addition to these implementations, when operating in the second mode, the second node is configured to send a transmit signal when a second signal from the humidity sensor exceeds a threshold.

[0014] A method is also provided, including determining that a microelectromechanical system (MEMS) device is no longer in an initialized state. The method also includes receiving a first signal indicating that the MEMS device performs acoustic activity detection, and receiving one or more acoustic signals. In addition, the method includes determining that an acoustic signal of the one or more acoustic signals satisfies a defined acoustic characteristic. The method may also include outputting a second signal including information indicating that the acoustic activity detection at the MEMS device is greater than the defined acoustic characteristic. In one example, the defined acoustic characteristic may include a spectral signal level or a signal power in a given spectrum.

[0015] According to some implementations, the method may include determining that the MEMS device is in a powered state and receiving a selection after determining an initialized state. According to some implementations, the method may include communicating with an external device via a communication interface. The communication interface may be a serial interface.

[0016] According to some implementations, receiving the first signal may include receiving the first signal at a selector node. According to some embodiments, outputting the second signal may include outputting the second signal at the selector node.

[0017] The method may further comprise stopping the external clock or reducing the frequency after receiving the first signal.Alternatively or additionally, the method may comprise receiving the defined acoustic characteristic during an initialisation state.

[0018] According to some implementations, the acoustic signal is a first acoustic signal, and the method may include determining, after a delay before receiving the clock signal, a second time that a second acoustic signal of the one or more acoustic signals satisfies the defined acoustic characteristic. In addition to these implementations, the method may also include, after the second determination, changing the defined acoustic characteristic.

[0019] Furthermore, according to some implementations, the method may include receiving a clock start signal or a clock at a normal operating frequency.Acoustic activity detection may be interrupted upon or after receipt of the clock start signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Various non-limiting embodiments are further described with reference to the accompanying drawings, in which:

[0021] Figure 1 An exemplary non-limiting device according to one or more embodiments described herein is shown;

[0022] Figure 2 An exemplary non-limiting protocol for read and write operations according to one or more embodiments described herein is shown;

[0023] Figure 3A flow chart illustrating an exemplary non-limiting computer-implemented method for acoustic activity detection signals using a shared selector node according to one or more embodiments described herein;

[0024] Figure 4 A flow chart illustrating an exemplary non-limiting computer-implemented method for acoustic activity detection signals using shared selector outputs and relative thresholds according to one or more embodiments described herein;

[0025] Figure 5 Another exemplary non-limiting device according to one or more embodiments described herein is shown;

[0026] Figure 6 An exemplary non-limiting MEMS sensor circuit for device identification detection of two or more sensors over a single-wire communication interface is shown according to one or more embodiments described herein; and

[0027] Figure 7 A flow chart is shown of an exemplary non-limiting computer-implemented method for event activity detection signals using shared selector outputs and relative thresholds in accordance with one or more embodiments described herein. DETAILED DESCRIPTION

[0028] One or more embodiments will be described more fully hereinafter with reference to the accompanying drawings, in which example embodiments are shown.In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of various embodiments.

[0029] Acoustic sensing is used to access the context of an event of interest (e.g., a human voice, activation of a smoke detector, breaking glass, a gunshot, or other acoustic event). For example, acoustic sensing may be used for security purposes or other purposes for which the context of one or more events of interest needs to be monitored. In most implementations, acoustic events of interest occur infrequently. Therefore, existing systems employ always-on (e.g., always listening) acoustic wake-up detectors to detect one-time events (e.g., breaking glass) and / or to detect critically important events. Additionally, existing systems need to react to audio wake-up activity, require significant (sometimes a lot) of power, are complex, and require time to analyze and quantify the audio content.

[0030] Existing acoustic activity detection systems or circuits may include a microphone and a voice processor with embedded acoustic activity detection circuitry, which may include embedded digital signal processing (DSP) functionality. The operation of such systems only allows the system to be awakened based on an "on" indication and / or an "off" indication that a sound pressure event has exceeded a specified decibel sound pressure level (dB SPL). Once this indication occurs, the system is fully powered on and a set of audio data is collected and processed to extract frequency and amplitude details. This data must then be analyzed to determine the next course of action. For example, the data is processed by a voice processor or other type of acoustic analyzer and a fast Fourier transform (FFT) is performed on the content, which is also passed through a series of algorithms to classify the events that occurred. This data processing can consume power and time.

[0031] One or more embodiments provided herein can facilitate a low power acoustic (and / or other event) activity detection signal circuit having a single output configured as a single-wire communication interface. A low acoustic (and / or other event) activity detection signal method utilizing the output as a single-wire communication interface is also provided.

[0032] First reference Figure 1 , an exemplary non-limiting device 100 according to one or more embodiments described herein is shown. According to some embodiments, the device can be a digital micro-electromechanical system (MEMS) device, a MEMS microphone, or another type of sensor device. Various embodiments discussed herein relate to acoustic activity detection. As described herein, acoustic activity detection is an ultra-low power edge processing feature in which a microphone (e.g., a MEMS microphone) monitors acoustic activity (e.g., an event of interest) in an environment and wakes up a system on chip (SoC) or application processor when acoustic activity is detected.

[0033] It is worth noting that acoustic signal detection is only one type of event that can be detected. On the contrary, other events can also be detected while sharing similar detection configurations and signal processes described herein. These other events include, but are not limited to, intelligent acoustic events, such as Voice Activity Detection (VAD), Keyword Spotting (KWS), Automatic Speech Recognition (ASR), etc. For example, intelligent acoustic events may include, but are not limited to: speech, keywords, collisions, explosions, gunshots, broken glass, etc.

[0034] Other events that can be detected are unsafe sound levels. For example, levels exceeding a defined dB SPL level (e.g., exceeding 130 dB SPL) can be considered unsafe and monitored as described herein.

[0035] Another event may be a built-in self-test (BIST) failure. For example, the internal self-test may be used to determine various conditions, including microphone health and / or condition and other component health and / or condition.

[0036] Still other events may be related to temperature conditions. For example, an over-temperature threshold and / or an under-temperature threshold may trigger another event detection. For example, such detection may be performed by an internal temperature sensor.

[0037] In another example, humidity and / or moisture can trigger another event. Humidity and / or moisture can be detected by, for example, an internal humidity sensor. In addition, another event can be pressure, which can be monitored by, for example, an internal pressure sensor. Ambient light conditions can be another triggering event, which can be evaluated by an internal light sensor.

[0038] Typically, when an event is detected, an event detection signal is sent to an external host processor or SoC, which will process the details related to the event and / or receive instructions based on the event detection. In order to detect the event, the microphone should be at the lowest possible power level because the microphone needs to be "always on" to detect the event. In some cases, as many circuits and components as possible can be powered off or disabled during microphone functionality, and only (or almost only) activity detection is active. At the time of detection or after detection, the occurrence of the detection needs to be communicated. Therefore, a signal method for performing communication with an external host processor, SoC, and / or another receiving component is provided herein.

[0039] Continue to refer Figure 1 , device 100 may include a MEMS transducer and circuitry for activity detection. Sensor 102 may include a digital MEMS transducer 104 and circuitry for processing one or more acoustic signals.

[0040] The device 100 can be coupled to the signal line 106 via a selector node 108. The selector node 108 can also be referred to as a selector output, a left / right (L / R) input, a MEMS transducer selector, etc. In some implementations, the selector node 108 can be a pin. The selector node 108 can be used for communication between one or more MEMS sensors in a system and multiple MEMS sensors (e.g., a package including a digital MEMS acoustic sensor 102), such as communication with a controller 110. According to some embodiments, the controller 110 can be an external controller. However, in some implementations, a chip or SoC may include the controller 110 and the digital MEMS acoustic sensor 102.

[0041] The device 100 may include an analog-to-digital converter (ADC) 112 coupled to a pulse density modulation (PDM) 114. The PDM modulator 114 receives an external clock (CLK 116) signal and provides a digital data (DATA 118) output signal of the device 100.

[0042] The device 100 may also include a channel selection component (not shown) coupled to a control interface component (not shown) at a control pin (e.g., an L / R select pin of the device 100) including the selector node 108. In some implementations, the device 100 may include a channel selection component (not shown) coupled to the V DD 120 node or pin and a power management component (not shown) at a GND 122 node or pin.

[0043] In more detail, the device 100 may be limited to defined inputs / outputs (e.g., defined pins) required for operation. Such inputs / outputs include power to an output interface for audio streaming data. Also included on the digital MEMS sensor are left and right (L / R) pins, referred to herein as selector nodes or selector inputs / outputs, which can be used to select a left or right microphone in a two-microphone system.

[0044] Typically, the selector output (L / R pin) is used for communication during testing. In some cases, the selector output can be used by the end user for configuration. As described in this article, the selector input, which was previously limited to initial setup functions, is used as a multi-function interface to also signal acoustic activity detection events. By leveraging the existing selector input, standard interfaces for digital MEMS sensors can be utilized, which can provide efficiencies in deployment and implementation.

[0045] Note that Figure 1 In an embodiment, the THSEL pin and the WAKE pin are not included in the device 100. For example, as shown, the THSEL pin and the WAKE pin included on other digital MEMS sensors have been removed. Alternatively, during the manufacturing process, the THSEL pin and the WAKE pin are not included on the device (e.g., not required). By removing (or not including) the THSEL pin and the WAKE pin, the device 100 is a five input / output (e.g., pin) configuration. This configuration includes the selector node 108, the CLK 116 output, the DATA 118 output, the V DD 120 node and GND 122 node.

[0046] As described herein, selector node 108 is used to implement the functions previously implemented by THSEL and WAKE pins, so that selector node 108 will share the first two functions previously used for polarity detection. It is worth noting that polarity detection is only valid during power-on. Therefore, according to one implementation, at the first initial power-on when the chip is started, selector node 108 reads the configuration of the internal register and reads the state of the left and right states. At the first initial power-on or after the first initial power-on, the left and right states are retained, and selector node 108 has no other functions in the remaining operations. Therefore, selector node 108 can be used as a communication interface for event activity detection as described herein.

[0047] According to one implementation, the selector node 108 is used as a communication interface to facilitate acoustic activity detection and / or other event activity detection configuration. In addition, acoustic activity detection and / or other event activity detection are configured and started by an activity detection start command using the selector node 108. Therefore, during the acoustic activity mode and / or other event activity mode, the selector node 108 is used as an input / output. When an event is detected, the output signal notification of this event is sent to other components via the selector node 108.

[0048] Figure 2 An exemplary non-limiting protocol for read and write operations according to one or more embodiments described herein is shown. For the sake of brevity, repeated descriptions of similar elements employed in other embodiments described herein are omitted.

[0049] Figure 2 A single write operation 200 is shown in FIG, which includes a device address 202, a register address 204, and register data 206, without the need to implement or require a signal to confirm (ACK) the receipt of the data. In the present embodiment, "S" represents a "start" bit and "P" represents a stop bit. According to one implementation, for example, the "start" bit and / or the "stop" bit can be generated by an external controller defined by a predefined control symbol. The device address 202 can be set to a default value (e.g., 7'h28) and / or can be changed to accommodate any of a variety of numbers and / or types of MEMS sensors. It is worth noting that the "stop" control symbol may appear at any position during the protocol. Therefore, whenever a "stop" control symbol is detected or determined, the MEMS sensor can be restored to a reset state to wait for a new "start" control system.

[0050] In this example, there is one pin (e.g., selector node 108) for communication of an event detection trigger. The selector output is configured as an OWCI configuration. OWCI is a bidirectional, single-wire communication interface. OWCI is a serial link that enables devices or sensors to communicate over a single line (e.g., one node, one pin). If data is to be written to a register in the microphone, the write operation can be performed using OWCI. Thus, a host processor can send communications to a MEMS sensor to perform an initial setup or to perform calibration. Writing to a register is what is known as a single-wire communication. The OWCI process refers to the host processor writing to the microphone register through this single node. Therefore, OWCI is a read / write access to the internal registers.

[0051] Upon or after receiving an indication or command to start event detection (e.g., received as an input on the OWCI), active event detection (e.g., AAD feature) is enabled 208. The detection mode is initiated upon or after the external clock stops, as shown at 210 (e.g., output by CLK 116). Upon or after the external clock stops or the clock frequency drops below the normal operating frequency, acoustic activity detection is enabled, after which detection may be performed, as shown at 212. Based on the detection of the defined event, output data indicating the occurrence of the detected event is sent via the selector node 108. Event detection may be stopped or discontinued upon receipt of a clock start signal or the clock frequency returns to the normal operating frequency.

[0052] With reference to various flow charts, the methods that can be implemented according to the disclosed subject matter will be better understood. Although these methods are shown and described as a series of blocks for the sake of simplicity of explanation, it should be understood and recognized that the disclosed aspects are not limited by the number or order of blocks, because some blocks can appear in different orders and / or substantially simultaneously with other blocks shown and described herein. In addition, not all blocks shown need to implement the disclosed methods. It should be understood that the functions associated with the blocks can be implemented by software, hardware, a combination thereof, or any other suitable means (e.g., equipment, system, process, assembly, etc.). In addition, it should be further understood that the disclosed methods can be stored on articles of manufacture, to facilitate the transportation and transfer of these methods to various devices. It will be understood and recognized by those skilled in the art that these methods can be alternatively represented as a series of interrelated states or events, such as in a state diagram.

[0053] Figure 3A flowchart of an exemplary non-limiting computer-implemented method 300 for acoustic activity detection signals using a shared selector node according to one or more embodiments described herein is shown. The computer-implemented method 300 may be implemented by a circuit (e.g., device 100, a MEMS microphone, a system including a processor, a temperature sensor, a humidity sensor, a pressure sensor, a light sensor, etc.).

[0054] The computer-implemented method 300 begins with initialization of the sensor. To initialize the sensor, at 302 of the computer-implemented method 300, the sensor is powered on and a CLK input is provided (e.g., received at a digital MEMS microphone, device, or other sensor). For example, a one-time programmable (OTP) memory is read and a microphone (MIC) is configured. The power-on and CLK input of the sensor may be provided during an IDLE mode.

[0055] At 304, the selector output (e.g., selector node 108) is configured as a one wire communication interface (OWCI). Thus, during initial power-up, the selector node can read the configuration of the internal registers and read the state of the selector node (e.g., L / R pin), for example, for polarity detection. After polarity detection (e.g., after initial power-up), the polarity state is retained and the selector output can be used for other functions, as described herein (e.g., as an OWCI).

[0056] At 306, the host processor sets the AAD parameters. For example, the AAD parameters may be received at the digital MEMS sensor. In addition, the AAD mode may be initialized on the OWCI. At 308, CLK is stopped and the internal oscillator (OSC) clocks the MIC. At 310, SEL is set to output "low". Activity detection is activated at this time (e.g., when or after the clock is stopped).

[0057] At 312, an acoustic signal is received and processed by the AAD. At 314, based on the AAD determining that the acoustic signal meets the detection threshold (e.g., exceeds the detection threshold), the SEL output is driven "high" for at least a minimum period of time. For example, the various "thresholds" discussed herein can be defined as simple amplitude values, moving averages, or moving root mean square (RMS) values. Alternatively, if the AAD determines that the acoustic signal does not meet the detection threshold, the digital MEMS sensor ignores the signal and continues to monitor the environment.

[0058] At 316, when the host processor detects the SEL change, CLK is enabled. After the CLK signal is detected at 318, the SEL output is "pull-up high" and the AAD mode is stopped. In addition, the MIC mode is set by the CLK frequency and the SEL is configured as OWCI. At this point, the MIC is ready to receive host processor instructions.

[0059] Figure 4 FIG. 4 is a flow chart of an exemplary non-limiting computer-implemented method 400 for acoustic activity detection signals using a shared selector output and a relative threshold according to one or more embodiments described herein. The computer-implemented method 400 is configured to operate without a host processor (with Figure 3 Compared to computer implemented method 300).

[0060] The computer-implemented method 400 begins with initialization of the sensor. To initialize the sensor, at 402 of the computer-implemented method 400, the sensor is powered on and a CLK input is provided (e.g., received at a digital MEMS sensor). For example, a one-time programmable (OTP) memory is read, and a microphone (MIC) is configured. Powering on the sensor and providing a CLK input may be performed during an IDLE mode.

[0061] At 404, the selector output (e.g., selector node 108) is configured as a single wire communication interface (OWCI). Thus, during initial power-up, the selector node can read the configuration of the internal registers and read the state of the selector node (e.g., L / R pin), for example, for polarity detection. After polarity detection (e.g., after initial power-up), the polarity state is retained and the selector node can be used for other functions, as described herein (e.g., as an OWCI).

[0062] At 406, the host processor sets the AAD parameters. For example, the AAD parameters may be received at the digital MEMS sensor. In addition, the AAD mode may be initialized in "relative threshold mode" on the OWCI. At 408, the CLK stops or receives a signal below the normal operating frequency, and the internal oscillator (OSC) clocks the MIC. At 410, the AAD threshold is set based on one or more AAD parameters. In addition, SEL is set to output "low".

[0063] An acoustic signal is received at 412 and processed by the AAD. At 414, a determination is made as to whether the acoustic signal exceeds a detection threshold. For example, the determination may be made after a delay. Additionally, the SEL output is driven "high". Based on a determination that the acoustic signal satisfies the detection threshold (e.g., reaches or exceeds the detection threshold), the AAD threshold is increased by a defined increase. Alternatively, if a determination is made that the acoustic signal fails to satisfy the detection threshold (e.g., is less than the detection threshold), the AAD threshold is reduced by a defined decrease. According to some embodiments, the defined increase and the defined decrease are different values, the same value, or a combination thereof. Additionally, the defined increase and / or the defined decrease may be configured.

[0064] The new value of the AAD threshold is stored in an internal register. In addition, the AAD threshold delay can be set by the OTP, OWCI register, or as a function of the AAD threshold.

[0065] At 416, when the host processor detects the SEL change, the host processor can determine whether to process the event. In addition, when or after the CLK signal is detected at 418, the SEL output is "pulled high" and the AAD mode stops. The MIC mode is set by the CLK frequency and the SEL is configured as OWCI. At this point, the MIC is ready to receive host processor instructions.

[0066] Figure 5 Another exemplary non-limiting device 500 according to one or more embodiments described herein is shown. For the sake of brevity, repeated descriptions of similar elements employed in other embodiments described herein are omitted.

[0067] Device 500 is similar to Figure 1 However, in the configuration of device 500, the THSEL pin and the WAKE pin are replaced by a communication interface 502. For example, the communication interface 502 may be an I2C interface, an I3C interface, a serial peripheral interface (SPI), or the like.

[0068] The communication interface 502 may be used to configure a microphone and / or AAD functionality. In another example, the communication interface 502 may be used to configure another type of sensor and / or another event detection functionality.

[0069] The selector node 108 can be shared for these functions. For example, as discussed, the selector node 108 (e.g., L / R pin) can be used for polarity detection during power-up. After power-up, the selector node 108 can be shared for event detection functions. For example, during production test and factory debugging (debug), the selector node 108 can be configured as an OWCI. In addition, the selector node 108 configured for OWCI communication can facilitate output based on event detection events (e.g., "wake up") and facilitate sending signals to the host processor in event detection mode.

[0070] In a specific example, the device 500 can measure an optical signal via an optical sensor in a microphone package and determine whether the optical signal exceeds a threshold optical signal threshold. Upon or after determining that the optical signal exceeds the threshold optical signal threshold, a signal is sent to a host processor via a communication interface 502 (e.g., an I2C interface). For example, a "threshold" can be defined as a simple amplitude value, a moving average, or a moving RMS value. More details related to the optical signal implementation can be found in U.S. patent application No. 17 / 174,890, filed on February 12, 2021, entitled "Optical Interference Identification in MEMS Microphones," the entire contents of which are expressly incorporated herein by reference.

[0071] Figure 6 An exemplary non-limiting MEMS sensor circuit 600 is shown for device identification detection of two or more sensors over a single-wire communication interface in accordance with one or more embodiments described herein.

[0072] As shown, the MEMS sensor circuit 600 includes two or more microphones with corresponding selector (sel) input / output (e.g., SEL pins), which are shown as a first microphone selector (MIC1 sel 602), a second microphone selector (MIC2 sel 604), a third microphone selector (MIC3 sel 606), and a fourth microphone selector (MIC4 sel 608). During initialization, each microphone can provide current (I) to the SEL pin after power-up, and OTP is read within a defined amount of time. After a defined delay, the voltage at the SEL input is measured while Io is still provided.

[0073] The voltage measurement is digitized by the increment of current times resistor (I*R). Each I*R measurement unit directly provides a microphone identifier or ID number. After a defined delay, the SEL pin is configured as OWCI 610. Upon completion, the Io current and MIC ID detection are disabled (e.g., turned off).

[0074] Thus, multiple microphones or other sensors can share the same communication bus, while each sensor is individually identifiable. For example, the size of each resistor (e.g., R, R / 2, R / 3, R / N) is utilized so that each microphone (e.g., MIC1 sel 602, MIC2 sel 604, MIC3 sel 606, MIC4 sel 608) obtains an internal identification number. The microphones communicate with the host processor using the internal identification number.

[0075] In one example, the various resistors can be weighted according to a program that allows each microphone to be programmed (during power-up) to output a fixed amount of current from a pin (e.g., selector node 108). The differently sized or weighted resistors increase the different voltages on each microphone pin, which are converted to unique identification numbers by an internal analog-to-digital converter. After all microphones are powered up and configured, corresponding identification numbers are assigned, allowing the host processor to communicate with each microphone individually. In this implementation, selector node 108 performs identification during power-up rather than polarity detection.

[0076] Figure 7 A flow chart is shown of an exemplary non-limiting computer-implemented method 700 for event activity detection signals using shared selector outputs and relative thresholds in accordance with one or more embodiments described herein.

[0077] The computer-implemented method 700 begins at 702 by determining that a microelectromechanical system (MEMS) device is no longer in an initialized state. When or after the device is no longer in an initialized state, a selector node may be used as a single-wire communication interface as described herein.

[0078] At 704, a first signal instructing the MEMS device to perform event activity detection may be received. According to one implementation, the first signal may be received at a selector node. In some implementations, the external clock is stopped after receiving the first signal. In other embodiments, after receiving the first signal, the clock frequency is lower than the normal operating frequency. Upon or after receiving the first signal, the MEMS device enters a detection state to detect a defined event. For example, the defined event may be acoustic detection, smart acoustic event detection, unsafe sound level detection, BIST fault detection, temperature detection, humidity detection, moisture detection, pressure detection, light detection, etc.

[0079] At 706, one or more signals associated with the event being detected are received. The one or more signals are analyzed, and at 708, it can be determined that an event signal in the one or more signals associated with the event satisfies a defined event characteristic. The defined event characteristic can be received during an initialization state.

[0080] For example, for light detection, the defined event characteristic may be the amount of light being above (or below) a defined threshold light level, the duration of light received being longer (or shorter) than a defined light duration, etc. In another example, for humidity and / or moisture detection, the defined event characteristic may be the amount of humidity or moisture detected being greater (or less) than a defined humidity or humidity threshold. For pressure detection, the defined event characteristic may be a threshold amount of pressure, or the duration of a defined amount of pressure. For temperature detection, the defined event characteristic may be a defined temperature and a detected temperature above (or below) the defined temperature that triggers an event.

[0081] Based on the determination at 708, at 710, a second signal is output, the second signal including information indicating that the event activity detected at the MEMS device is greater than a defined event characteristic. In an example of event activity detection, the defined event characteristic may be a spectral signal level. Outputting the second signal may include outputting the second signal at a selector node.

[0082] In some implementations, the computer-implemented method 700 may include determining that the MEMS device is in a powered state and receiving a selection after determining an initialized state. Alternatively or additionally, the computer-implemented method 700 may include communicating with an external device via a communication interface. In one example, the communication interface may be a serial interface.

[0083] In some implementations, the computer-implemented method 700 may include determining, after a delay before receiving the clock signal, a second time that an event signal in the one or more event signals satisfies a defined event characteristic. In addition to these implementations, after the second determination, the computer-implemented method may include changing the defined event characteristic.

[0084] Additionally, the computer-implemented method 700 may include receiving a clock start signal. Based on receiving the clock start signal, event activity detection may be interrupted.

[0085] References throughout this specification to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic associated with the embodiment is included in at least one embodiment. Therefore, the phrases "in one embodiment," "in one aspect," or "in an embodiment" appearing in various places in this specification do not necessarily all refer to the same embodiment. Furthermore, in one or more embodiments, the particular features, structures, or characteristics may be combined in any suitable manner.

[0086] In addition, the words "example" and "exemplary" as used herein refer to serving as an example or illustration. Any embodiment or design described herein as "example" or "exemplary" is not necessarily to be construed as superior to other embodiments or designs. On the contrary, the use of the words "example" or "exemplary" is intended to present concepts in a concrete way. The term "or" used in this application is intended to mean an inclusive "or" rather than an exclusive "or". That is, unless otherwise specified or clear from the context, "X uses A or B" is intended to mean any natural inclusive arrangement. That is, if X uses A; X uses B; or X uses both A and B, then in any of the above cases, "X uses A or B" is true. In addition, the articles "a" and "an" used in this application and the appended claims should generally be interpreted as "one or more" unless otherwise specified or clear from the context to be in the singular form.

[0087] Furthermore, the various embodiments may be implemented as a method, apparatus, or article of manufacture using standard programming and / or engineering techniques to produce software, firmware, hardware, or any combination thereof to control a computer to implement the disclosed subject matter. The term "article of manufacture" as used herein is intended to encompass a computer program accessible from any computer-readable device, machine-readable device, computer-readable carrier, computer-readable medium, machine-readable medium, computer-readable (or machine-readable) storage / communication medium. For example, a computer-readable medium may include, but is not limited to, magnetic storage devices such as hard disks; floppy disks; magnetic strips; optical disks (e.g., compact disks (CDs), digital video disks (DVDs), Blu-ray discs, etc.); TM (BD)); smart card; flash memory device (e.g., card, stick, key drive); and / or a virtual device that emulates a storage device and / or any of the above computer-readable media. Of course, those skilled in the art will recognize that many modifications may be made to this configuration without departing from the scope or spirit of the various embodiments.

[0088] The above description of the illustrated embodiments of the present disclosure, including what is described in the Abstract, is not intended to be exhaustive or to limit the disclosed embodiments to the precise forms disclosed. Although specific embodiments and examples are described herein for illustrative purposes, those skilled in the relevant art will recognize that various modifications may be made within the scope of these embodiments and examples.

[0089] In this regard, while the subject matter is described herein in conjunction with various embodiments and corresponding figures, it is understood that other similar embodiments may be used, or modifications and additions may be made to the described embodiments, to perform the same, similar, alternative, or alternative functions of the disclosed subject matter without departing therefrom. Therefore, the disclosed subject matter should not be limited to any single embodiment described herein, but rather should be construed in breadth and scope in accordance with the following appended claims.

Claims

1. A device comprising: Micro-electromechanical systems (MEMS) transducers; A circuit for activity detection, wherein the circuit comprises: A first node configured to send or receive data associated with a clock signal; and A second node is configured to operate in a first mode during a power-up phase of the device and to operate in a second mode after the power-up phase of the device is completed, wherein the second node is configured to receive a signal that causes the device to perform the activity detection based on an activity determination.

2. The device according to claim 1, wherein: The clock signal is below normal operating frequency or has stopped at the first node.

3. The device according to claim 1, wherein: The circuit also includes a third node configured to transmit one or more acoustic signals.

4. The device according to claim 1, wherein: When operating in the second mode, the second node is configured as a communication interface for the activity detection.

5. The device according to claim 4, wherein: The communication interface includes at least one of transmitting a signal or receiving a signal associated with the activity detection.

6. The device according to claim 4, wherein: The communication interface facilitates write access and read access to internal registers associated with the MEMS transducer.

7. The device according to claim 4, wherein: The communication interface is a serial interface.

8. The device according to claim 1, wherein: The MEMS transducer includes a MEMS acoustic sensor that receives an acoustic signal including an acoustic signal frequency.

9. The device according to claim 1, wherein: The second node is a MEMS transducer selector pin.

10. The device of claim 1, further comprising a serial interface for communicating with an external device.

11. The device according to claim 1, wherein: The activity detection is based on acoustic activity, the acoustic activity comprising one of: voice, keyword, collision, explosion, gunshot, breaking glass, unsafe sound level, built-in self-test failure, over-temperature threshold, and under-temperature threshold.

12. The device according to claim 1, wherein: The signal is a first receive signal, and wherein the device further comprises a light sensor, and when operating in the second mode, the second node is configured to send a transmit signal when a second signal from the light sensor exceeds a threshold.

13. The apparatus according to claim 1, wherein: The signal is a first receive signal, and wherein the device further comprises a humidity sensor, and when operating in the second mode, the second node is configured to send a transmit signal when a second signal from the humidity sensor exceeds a threshold.

14. The device of claim 1, the voltage at the second node indicating a position of the device in a system of devices.

15. A method comprising: Determining that the micro-electromechanical system (MEMS) device is no longer in an initialization state; receiving a first signal instructing the MEMS device to perform acoustic activity detection; receiving one or more acoustic signals; determining that an acoustic signal among the one or more acoustic signals satisfies a defined acoustic characteristic; as well as A second signal is output, the second signal including information indicating that acoustic activity detected at the MEMS device is greater than the defined acoustic characteristic.

16. The method according to claim 15, further comprising: Determining that the MEMS device is in a powered state; as well as A selection is received after determining the initialization state.

17. The method according to claim 15, wherein: The defined acoustic characteristics include spectral signal levels.

18. The method according to claim 15, wherein: Receiving the first signal includes receiving the first signal at a selector node.

19. The method according to claim 15, wherein: Outputting the second signal includes outputting the second signal at a selector node.

20. The method of claim 15, further comprising: After receiving the first signal, the external clock is stopped or the frequency is reduced.

21. The method of claim 15, further comprising: The defined acoustic characteristics are received during the initialization state.

22. The method according to claim 15, wherein: The acoustic signal is a first acoustic signal, and wherein the method further comprises: After a delay before receiving the clock signal, a second acoustic signal of the one or more acoustic signals is determined a second time to satisfy the defined acoustic characteristic.

23. The method according to claim 22, further comprising: After the second determination, the defined acoustic property is changed.

24. The method of claim 15, further comprising: receiving a clock enable signal or a clock at a normal operating frequency; as well as The acoustic activity detection is interrupted.

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