The Tone Audio Module is a line-level audio source and analyzer that plugs into the Accordion test platform as an SO-DIMM module. It generates test tones on two DAC channels and measures frequency, RMS, peak-to-peak, THD, and SNR on four switched ADC inputs — all locally, with only commands and scalar results crossing the backplane. Audio test steps stay deterministic without consuming Accordion’s data path.

At a glance

• Form factor: SO-DIMM
• Sample rate / depth: 96 kSps, 24 bit (fixed)
• Outputs: 2 × DAC, line level, programmable gain per channel
• Inputs: 4 × 2 multiplexed ADC, line level, programmable gain
• Waveforms: Sine, Square, Sawtooth, Noise
• Measurements: Frequency, V_rms, V_pp, THD, SNR
• Host interface: UART command protocol; 6 GPIO for peripheral control

What it does

Audio generation runs continuously once configured. Set the waveform, frequency, and per-channel gain on either DAC; the module produces the tone without further sample streaming from the host. The two output channels are independent.

Measurement runs on the four multiplexed ADC inputs, organized as 4 × 2 with programmable input gain. Sampling, DSP, and metric extraction execute on the module, so the host receives processed scalars — frequency, V_rms, V_pp, THD, SNR — rather than raw sample streams. Test step time stays predictable, and 96 kSps × 24-bit data never has to cross the Accordion backplane.

Trade-offs are explicit. All external interfaces are line level; the internal I²S and DSP paths are not exposed externally. Sample rate and bit depth are fixed in hardware. Applications that need speaker-level drive or raw sample capture sit outside this module’s scope.

How it fits into Accordion

The module operates as a server in a client–server pattern over UART: Accordion issues configuration, control, and result-retrieval commands; the module exposes audio generation and measurement as high-level operations. Raw audio never leaves the module, so backplane usage stays minimal regardless of how often a test sequence calls into it.

Six GPIO pins are available for peripheral control around the audio path — switching loads, muting paths, asserting test points — under the same UART control surface, so a complete audio test step can be expressed without reaching outside the module.

Typical use

• End-of-line audio test on consumer and embedded products with line-level inputs and outputs
• Automated frequency response, level, THD, and SNR sweeps in production test sequences
• Audio subsystem verification during board bring-up and NPI
• Stimulus generation for AGC, mixer, and codec validation

Full specifications

The full datasheet — electrical specs, the UART command protocol, GPIO assignments, supported measurement modes, and the connector pinout — lives in the E-Sharp help center. See ESH10000560 – Tone Audio Module for the complete reference.