Dimitri Becker

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8 years, 5 months ago.

Bad Audio at USB loopback on FRDM-KL46

ThreadUP!!! This is very annoying issue, please help me here

Hello all. I’ve compiled the simple USBAudioPlayback program at FRDM-KL46 board (using USBDevice/USBAudio library) and the Audio sound very choppy Short recorded loopback example : https://dl.dropboxusercontent.com/u/25364971/FRDM-46Z_USB-loopback.wav

Pseudo Code:

<< WHILE (1) { usbAudio.readWrite ( pointer1, pointer2); Swap_pointers; } >>

This is very simple programm, same works well at LPC Xpresso 11U68 Board and also on mbed NXP LPC1768 Board

Looks like a major bug in USB AudioDevice library for this MCU

Please HELP me solving this issue! ! ! Could someone confirm this or point me to possible solution

Best regards

2 Answers

Norimasa Okamoto
8 years, 5 months ago.

USBAudio use EP3IN/OUT.
but USBDevice/USBHAL_KL25Z.cpp not work EP3IN/OUT or else high endpoints.
https://developer.mbed.org/users/va009039/code/KL25Z_USBDevice/rev/e100852c1399

Hi Norimasa

Unfortunately, with your changes it doesn't work at all, I have no Audio at USB-loopback. What do you mean " USBHAL_KL25Z.cpp not work EP3IN/OUT or else high endpoints "?

Could you explain it a bit more

Best regards Dimitri

posted by Dimitri Becker 19 Nov 2015
Hirosh Dabui
8 years, 5 months ago.

Hi Norimasa,

could you give us a hint, how to solve the problem?

br,

Hirosh