SimpleLink SDK Voice Detection Plugin Release Notes

Table of Contents


The SimpleLink SDK Voice Detection Plugin is a low-resource speech recognition library for SimpleLink MCU devices. The plugin provides the following two libraries for voice detection applications:

This is version 1_50_00_15 of the SimpleLink SDK Voice Detection Plugin.


Please refer to the following documentation for in-depth documentation on using the SimpleLink SDK Voice Detection Plugin:

What’s New

Upgrade and Compatibility Information

This release has been validated against version of the SimpleLink MSP432 SDK.

Host Support


This release requires the following other software components and tools.

Device Support

Resources and Specifications

This section provides estimates of the resources needed for operation of SimpleLink SDK Voice Detection Plugin.

Memory Resources

The SimpleLink SDK Voice Detection Plugin library code size is about 23kB. The memory required to store model data depends on the maximum model size required. This release uses one flash sector of 4kB per model. SimpleLink SDK Voice Detection Plugin requires approximately 3kB of RAM that must persist as long as SimpleLink SDK Voice Detection Plugin is being used. During model training and recognition search additional temporary RAM is required for computation. For creating (enrolling) a model 4kB temporary RAM is required. For updating a model 11kB of temporary RAM is needed. For recognition search 250 bytes per model is required.

Processing Cycles

Processor cycle requirements are a complex function of the trained models, the input speech data and background noise, and the quality of the match between the trained data and the input speech. As a general rule, when there is less background noise and the input speech matches a model well, then cycle usage decreases during active recognition search. When there is no speech and background noise is low or at a moderate level and not changing appreciably, SimpleLink SDK Voice Detection Plugin will assume the signal is in a background noise condition and enter a background processing mode. When speech is present, or when other background noises are appreciable and varying, then SimpleLink SDK Voice Detection Plugin will enter the active recognition search mode to attempt to match the audio signal to a model, thus causing higher cycle usage. The table below provides estimates of typical cycle usage measured while running the SimpleLink SDK Voice Detection Plugin example demo program on the MSP432P401R operating at a clock rate of 48MHz . Due to variations in models, background noise, audio quality, and other factors the actual cycles an application requires may differ from these estimates.

Condition Average MCPS (% of Available Cycles) Maximum MCPS (% of Available Cycles)
Background Mode 2 (4.3%) 2 (4.3%)
Active Search Mode (1 model) 6.2 (13%) 7.7 (16%)
Active Search Mode (5 models) 17.3 (36%) 22.1 (46%)

Power Consumption

The SimpleLink SDK Voice Detection Plugin speech recognizer consumes arrays of sampled audio data. Typically the arrays consist of 160 samples collected at an 8kHz sample rate, so an array of data is provided to SimpleLink SDK Voice Detection Plugin each 20ms. The power needed to process these arrays is based on the cycles required for processing the data arrays, which was discussed in the prior paragraph. The total power consumption of an application will in addition depend heavily on hardware and application design. For lowest power operation the design should utilize low-power best practices. The hardware should use low-power components for audio collection, such as the microphone and pre-amplifier. The application should shut down peripherals during periods when they are not being used and use the lowest clocking rates necessary. Application software should utilize the low-power modes of the processor, such as LPM3, during idle times. Excluding the external hardware, estimates of processor power consumption for an application utilizing these practices ranges from 250uA in background mode to 1.8mA in active search mode with five models active.

The current SimpleLink SDK Voice Detection Plugin example program demonstrates the use of the SimpleLink SDK Voice Detection Plugin speech recognizer, but for simplicity of illustration it was not designed for lowest power operation. For example, during idle times it uses LPM0 and the 48MHz clock remains running.

Validation Information

The MSP432 SimpleLink SDK was validated with the following components:

Known Issues



This product’s version follows a version format,, where M is a single digit Major number, mm is 2 digit minor number, pp is a 2 digit patch number, and b is an unrestricted set of digits used as an incrementing build counter.

Prior Release Changes

Technical Support and Product Updates