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USBD_Audio_OS_DlyMs

USBD_Audio_OS_DlyMs

Dec 03, 2020

Description

Delay a task for a certain time.

Files

usbd_audio_os.h / usbd_audio_os.c

Prototype

void USBD_Audio_OS_DlyMs (CPU_INT32U ms);

 

Arguments

ms

Delay in milliseconds.

Returned Value

None.

Callers

Audio Class.

Implementation guidelines

  1. The RTOS layer code should delay the calling task by the specified number of milliseconds.

OS Tick Rate

Whenever possible, USBD_Audio_OS_DlyMs() should provide a delay with a 1 ms granularity. That is the OS tick rate should be set to produce at least 1 tick per millisecond. It will help for the audio class tasks scheduling as audio class works on a 1 ms frame basis. Moreover, a retry mechanism is implemented in the playback and record tasks in case a transfer cannot be queued on a given endpoint. The playback or record task waits 1 ms between each attempt before re-transmitting the transfer.