Freescale Semiconductor i.MX 6DualLite, Справочное руководство

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Chapter 26
Asynchronous Sample Rate Converter (ASRC)
Driver
26.1 Introduction
The Asynchronous Sample Rate Converter (ASRC) converts the sampling rate of a signal
to a signal of different sampling rate. The ASRC supports concurrent sample rate
conversion of up to 10 channels. The sample rate conversion of each channel is
associated to a pair of incoming and outgoing sampling rates. The ASRC supports up to
three sampling rate pairs simultaneously.
26.1.1 Hardware Operation
• Supports ratio (Fsin/Fsout) ranging from 1/24 to 8.
• Designed for rate conversion between 44.1 KHz, 32 KHz, 48 KHz, and 96 KHz.
• Other input sampling rates in the range of 8 KHz to 100 KHz are also supported, but
with less performance (see IC spec for more details).
• Other output sampling rates in the range of 30 KHz to 100 KHz are also supported,
but with less performance.
• Automatic accommodation to slow variations in the incoming and outgoing sampling
rates.
• Tolerant to sample clock jitter.
• Designed mainly for real-time streaming audio usage. Can be used for non-realtime
streaming audio usage when the input sampling clocks are not available.
• In any usage case, the output sampling clocks must be activated.
• In case of real-time streaming audio, both input and output clocks need to be
available and activated.
• In case of non-realtime streaming audio, the input sampling rate clocks can be
avoided by setting ideal-ratio values into ASRC interface registers.
i.MX 6Solo/6DualLite Linux Reference Manual, Rev. L3.0.35_4.1.0, 09/2013
Freescale Semiconductor, Inc. 191