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TOPIC: USBStreamer Kit TDM support at Low Sample Rates

USBStreamer Kit TDM support at Low Sample Rates 2 years 10 months ago #34560

  • p3droml
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Hi folks and hopefully some miniDSP administrators,

I'm considering buying the USBStreamer Kit to use with EV_ICS-52000-ARRAY, using an 8ch TDM array configuration @ low sample rates (11.025KHz).

In USBStreamer's datasheet it says TDM firmware support 8ch in @ 44.1/48k.

Can't TDM firmware also support low sample rates as Low Sample Rate firmware does?

EV_ICS-52000-ARRAY: www.digikey.com/product-detail/en/tdk-in...1428-1125-ND/7319749

Thanks in advance,
Pedro
Last Edit: 2 years 10 months ago by p3droml.
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USBStreamer Kit TDM support at Low Sample Rates 2 years 10 months ago #34679

  • devteam
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@ Pedro

I'm afraid that TDM support is only at 44.1 and 48k. No low sample rate I'm afraid

DevTEam
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USBStreamer Kit TDM support at Low Sample Rates 2 years 10 months ago #34706

  • p3droml
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Hi @DevTeam,

thank you for your reply. I've already ordered a USBStreamer Kit and I was reviewing the User Manual when realized about the following issues/errors:

1. At 2.2.3 TDM Clock lines, BCLK/LRCLK ratio is not 64, but 256. This ratio is the recommended one for 5-8 Microphone Arrays, but not for 1-4, as shown in Table 8. SCK Frequency from DS-000121-ICS-52000-v1.3.
2. TDM Protocol is made up of only three signals, MCLK is not used (It could be used if a codec is involved).
3. No TDM Data lines are shown in the User Manual, but I2S Data lines show LRCLK (also known as FSYNC or WS) polarity is negative, the beginning is indicated by the falling edge, instead of the rising edge as always used by TDM protocol. See 1.2 Frame Synchronization Pulse from AN301 or TDM DATA INTERFACE from DS-000121-ICS-52000-v1.3.
4. BCLK (also known as SCLK), as per Figure 31, uses negative polarity again. TDM Data Interface use positive polarity (rising edge) instead.
5. I assume 24 Word Length (2's compliment, MSB first) is used on 32 bit/channel, so that 25-32 bits are ignored (zero-value).

Please, clarify TDM Data Lines and clocks. I'm worried USBStreamer Kit not being compatible with the 4/8 ICS-52000 Microphone Array board I'm using.
Last Edit: 2 years 10 months ago by p3droml.
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USBStreamer Kit TDM support at Low Sample Rates 2 years 10 months ago #34753

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In order to get better assistant and to help other users who may have the same issues I've opened a new topic here.

I've already received the USBStreamer Kit and I've been able to do some checks myself :laugh:
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