RASynBoard schematic / dual microphone / far field support

The schematic is not public, but the RASynBoard Development Guide document provides the level of hardware details that you are likely looking for (including the interface details for additional microphones) http://avnet.me/rasynboard-ug

Regarding the 2nd microphone, this was prototyped and tested by Avnet (the out-of box application also includes software support for the optional 2nd microphone), but this 2nd microphone option is not currently available for purchase.

Thank you Peter for the very prompt reply. Does the DSP package permit the background noise cancellation support (ie.loud music playing  and the NDP120 can still pickup the wake word / commands) ? Very interested to test this support which is lacking on the nicla voice single microphone board.

Ongoing work is being done in this area. Theoretically, the 2nd mic will provide significant improvement in extracting keywords in a noisy environment, but we've seen mixed results thus far, with more refinement of this function still needed.   

PS: Reason for the extended form-factor of the 2nd microphone add-on PCB assembly, is the requirement to have at least 71mm spacing between the two mics.

Thank you again Peter. Do not want to outstay my welcome but curious on the following:

1) are the PDM microphones specific to the applied firmware? That is, can we switch out the TDK MMICT5832 with perhaps the IM67D130AXTSA2 (Infineon)?

2) Would the microphone on the aux shown paddleboard be the same as the primary TDK microphone?

3) Are the DSP files user created or supplied by Syntiant?

This looks to be a very thought out board. You have answered most of the questions within a few minutes that have yet to be commented on by the factory on their rather dormant user forum. It appears they are only after the big fish to keep their (led) lights on. We faced issues with even the nicla voice upon start up. Posted the full solution and corrected procedure on the Edge Impulse user forum.

Very excited to test your board asap - ETA tomorrow / Friday.

Thanks again!!

1) Are the PDM microphones specific to the applied firmware?
    Can we switch out the TDK MMICT5832 with perhaps the IM67D130AXTSA2 (Infineon)?
Having a mix of different mics is not recommended, as the TDK and Infineon mics have different characteristics

2) Would the microphone on the aux shown paddleboard be the same as the primary TDK microphone?
>> Yes, an identical TDK MMICT5832 part# is used for the second microphone

3) Are the DSP files user created or supplied by Syntiant?
>> Yes, Syntiant provide a DSP files for single mic and dual mic use cases
The relevant DSP .synpkg binaries can be accessed within the ndp120/synpkg_files folder, of the out-of-box application
https://github.com/Avnet/RASynBoard-Out-of-Box-Demo/tree/rasynboard_v2_tiny/ndp120/synpkg_files 

PS: Dual mic operation can be selected without rebuilding the application
Simply set Mode=2 under the [NDP Firmware] section in the config.ini file: 

[NDP Firmware]
# select the function mode. This defines which [Function_x]
# block will be used. Function blocks define which images
# to load into the NDP120
# 1->Function_1;
# 2->Function_2;
# 3->Function_3; ...
Mode=2

[Function_1]
Description="Single Mic"
MCU=mcu_fw_120.synpkg
DSP=dsp_firmware.synpkg
DNN=menu_demo_512_general_newph_v103_rasyn_pdm0_ext_icm.synpkg

[Function_2]
Description="Dual Mic"
MCU=mcu_fw_120.synpkg
DSP=dsp_firmware_noaec_ff.synpkg
DNN=menu_demo_512_noaec_newph_v103_rasyn_pdm0_ext_icm.synpkg

Anecdotal feedback from Syntiant was that the TDK T5838 microphone is significantly (~4x) more sensitive than the Infineon IM69D130 microphone on their NDP9120 EVB board

Excellent advice. Is the DSP binary available from Avnet or Syntiant to allow us to test with_aec feature? The impressive youtube demos is what we wish to replicate using 2 x microphones. We will remain with the referenced TDK microphones and will also consider to source the TDK EVB that offers support of 2 x flex microphones that will demonstrate the quality of the audio pickup over USB and audacity. Will request the same DSP files on their user forum but the factory support has been quite weak on past questions.

Does the RASynBoard make use of the AAD feature in the TDK microphone (wake on audio thresholds) to allow for further sleep mode current savings? Based on the paddle board pinout, perhaps not? If yes, which GPIO pin is monitoring for this IRQ event?

The results we wish to replicate:

www.youtube.com/watch

Hi mon2,

My name is Brian and I'm one of the developers supporting the Avnet RASynBoard.  I'm just back from PTO and can offer assistance in this thread.

You asked about the AAD TDK feature.  This is not currently supported; I would have to look into what it would take to enable this feature as the microphone is managed by the NDP120 firmware.  I'll open a dialog with Syntiant to see what's possible.

Regarding the two microphone performance.  We currently have an older RASynBoard image that works with the alexa model that's showcased in the video link you provided.

We're currently updating the RASynBoard firmware to support the latest Syntiant SDK and along with that work I've requested single and dual-mic Alexa models that can run on the RASynBoard.  I think this is still 2-3 weeks away from a public release.  I'll be sure an update this thread once it's been releases.