# AMB21 with SDK, config as USBd UAC device, recording fail. Big noise and frequence lower **URL:** \ **Category:** USB\ **Tags:** rtl872xd\ **Created:** [February 5, 2024, 2:03pm UTC](https://forum.amebaiot.com/t/amb21-with-sdk-config-as-usbd-uac-device-recording-fail-big-noise-and-frequence-lower/2669 "2024-02-05T14:03:17Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![Lin\_Nick](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.amebaiot.com/lin_nick/32/357_2.png) [@Lin\_Nick](https://forum.amebaiot.com/u/Lin_Nick)\ **Post date:** [February 5, 2024, 2:03pm UTC](https://forum.amebaiot.com/t/amb21-with-sdk-config-as-usbd-uac-device-recording-fail-big-noise-and-frequence-lower/2669/1 "2024-02-05T14:03:17Z")
Hi Sir, I have a AMB21 board, connected to PDM dmic as tensor flow lite example ( the dmic is the same as the example) [https://www.amebaiot.com/zh/amebad-arduino-audio-tensorflow-microspeech/](https://www.amebaiot.com/zh/amebad-arduino-audio-tensorflow-microspeech/) And I build the firmware from SDK, and config as USB device/UAC (old), the result is NG. Very much noise and tone become lower. Is there anything I could check ? I had wired the PDM direct to the pin on the board, but not much difference. Thanks Nick ---
**Author:** ![Lin\_Nick](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.amebaiot.com/lin_nick/32/357_2.png) [@Lin\_Nick](https://forum.amebaiot.com/u/Lin_Nick)\ **Post date:** [February 15, 2024, 2:40am UTC](https://forum.amebaiot.com/t/amb21-with-sdk-config-as-usbd-uac-device-recording-fail-big-noise-and-frequence-lower/2669/2 "2024-02-15T02:40:46Z")
Is there any response ? ---
**Author:** ![Kelvin\_Huang](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.amebaiot.com/kelvin_huang/32/2130_2.png) [@Kelvin\_Huang](https://forum.amebaiot.com/u/Kelvin_Huang)\ **Post date:** [February 15, 2024, 6:17am UTC](https://forum.amebaiot.com/t/amb21-with-sdk-config-as-usbd-uac-device-recording-fail-big-noise-and-frequence-lower/2669/3 "2024-02-15T06:17:51Z")
Hi @Lin_Nick, Can you send your code or screenshots of your serial monitor? Thank you. ---
**Author:** ![Kelvin\_Huang](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.amebaiot.com/kelvin_huang/32/2130_2.png) [@Kelvin\_Huang](https://forum.amebaiot.com/u/Kelvin_Huang)\ **Post date:** [February 16, 2024, 7:24am UTC](https://forum.amebaiot.com/t/amb21-with-sdk-config-as-usbd-uac-device-recording-fail-big-noise-and-frequence-lower/2669/5 "2024-02-16T07:24:23Z")
Hi @Lin_Nick , I am confused…Are you running code from Arduino SDK or Standard SDK? What example are you running? Thank you. ---
**Author:** ![Lin\_Nick](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.amebaiot.com/lin_nick/32/357_2.png) [@Lin\_Nick](https://forum.amebaiot.com/u/Lin_Nick)\ **Post date:** [February 16, 2024, 2:12pm UTC](https://forum.amebaiot.com/t/amb21-with-sdk-config-as-usbd-uac-device-recording-fail-big-noise-and-frequence-lower/2669/6 "2024-02-16T14:12:06Z")
Hi @Kelvin_Huang I running code from SDK. And the wiring is reference to Arduino Example, so I change the pin assignment . It there anything wrong ? Thanks for your help ---
**Author:** ![Kelvin\_Huang](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.amebaiot.com/kelvin_huang/32/2130_2.png) [@Kelvin\_Huang](https://forum.amebaiot.com/u/Kelvin_Huang)\ **Post date:** [February 17, 2024, 6:50am UTC](https://forum.amebaiot.com/t/amb21-with-sdk-config-as-usbd-uac-device-recording-fail-big-noise-and-frequence-lower/2669/7 "2024-02-17T06:50:24Z")
Hi @Lin_Nick , Which example is this? [GitHub - ambiot/ambd\_sdk: Release SDK for AmebaD](https://github.com/ambiot/ambd_sdk) Thank you. ---
**Author:** ![Lin\_Nick](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.amebaiot.com/lin_nick/32/357_2.png) [@Lin\_Nick](https://forum.amebaiot.com/u/Lin_Nick)\ **Post date:** [February 17, 2024, 10:06am UTC](https://forum.amebaiot.com/t/amb21-with-sdk-config-as-usbd-uac-device-recording-fail-big-noise-and-frequence-lower/2669/8 "2024-02-17T10:06:07Z")
Hi @Kelvin_Huang ``` That SDK cannot build USB/UAC example, for missing usb_f_uac1.o. I just want to record from PDM dmic, is it possilbe ? Thanks, Nick ``` ---
**Author:** ![Lin\_Nick](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.amebaiot.com/lin_nick/32/357_2.png) [@Lin\_Nick](https://forum.amebaiot.com/u/Lin_Nick)\ **Post date:** [February 19, 2024, 12:24am UTC](https://forum.amebaiot.com/t/amb21-with-sdk-config-as-usbd-uac-device-recording-fail-big-noise-and-frequence-lower/2669/9 "2024-02-19T00:24:22Z")
Hi @Kelvin_Huang Sorry for make you confused, please ignore previous message. I build the USBd/UAC example from SDK from other team in my company. The SDK version is sdk-amebad\_v6.2C-RC, plus patch. It contains a UAC old example, that’s it. ``` I need to build a UAC with pdm for internal study. Some other solution has quality issue. Please teach me Thanks, Nick ``` ---
**Author:** ![M-ichae-l](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.amebaiot.com/m-ichae-l/32/33_2.png) [@M-ichae-l](https://forum.amebaiot.com/u/M-ichae-l)\ **Post date:** [February 19, 2024, 2:55am UTC](https://forum.amebaiot.com/t/amb21-with-sdk-config-as-usbd-uac-device-recording-fail-big-noise-and-frequence-lower/2669/10 "2024-02-19T02:55:59Z")
> [@Lin\_Nick](#): > > sdk-amebad\_v6.2C-RC Looks like this is not an opensource SDK suitable for this forum. ---
**Author:** ![Lin\_Nick](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.amebaiot.com/lin_nick/32/357_2.png) [@Lin\_Nick](https://forum.amebaiot.com/u/Lin_Nick)\ **Post date:** [February 19, 2024, 3:04am UTC](https://forum.amebaiot.com/t/amb21-with-sdk-config-as-usbd-uac-device-recording-fail-big-noise-and-frequence-lower/2669/11 "2024-02-19T03:04:57Z")
Hi @Kelvin_Huang It looks like. BTW, any suggestion so I can find the problem ? Thanks ---
**Author:** ![Kelvin\_Huang](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.amebaiot.com/kelvin_huang/32/2130_2.png) [@Kelvin\_Huang](https://forum.amebaiot.com/u/Kelvin_Huang)\ **Post date:** [February 19, 2024, 5:26am UTC](https://forum.amebaiot.com/t/amb21-with-sdk-config-as-usbd-uac-device-recording-fail-big-noise-and-frequence-lower/2669/12 "2024-02-19T05:26:47Z")
Hi @Lin_Nick , > [@Lin\_Nick](#): > > The SDK version is sdk-amebad\_v6.2C-RC This SDK version is NDA. Code from NDA SDK are not supposed to be publicly discussed in open source SDK. You may check with the other team in your company to check with the assigned FAE for technical support. Thank you.