PCM1865设备状态总是fade in状态

JS Cao

Other Parts Discussed in Thread: PCM1865

Hi,TI的工程师们:

我现在使用PCM1865芯片来实现AD转换,主控芯片选择的是STM32,使用I2C作为控制接口,使用I2S作为输出接口,PCM1865的时钟源,我选择的是STM32的I2S控制器的MCLK,各时钟输出数据为BCK = 512KHz(64fs), LRCK = 8KHz, MCLK = 2MHz(256fs), fs = 8KHz,但是我读取page0,寄存器0x72(114)时,设备的状态是fade in而不是run,以至于我无法从I2S中接收到转换后的数据.因此,我现在的问题是,如何配置PCM1865来使设备进行AD转换从而使I2S输出数据.下图是我读取到的格寄存器的值:

9 年多前

0 user151383853 9 年多前

Guru 63421 points

手册有关这个介绍:

8.16 Fade-In and Fade-Out Functions
The PCM186x has Fade-In and Fade-Out functions on DOUT to avoid pop noise. This function is engaged on device power up/down and mute/unmute. The level changes from 0dB to mute or mute to 0dB are performed using pseudo S-shaped characteristics calculation with zero cross detection. Because of the zero cross detection, the time needed for the Fade-In and Fade-Out depends upon the analog input frequency (fIN). Fade takes 48/fIN until processing is completed. If there is no zero cross during 8192/fS, DOUT is faded in or out by force during 48/fS (TIME OUT). Figure 38 illustrates the Fade-In and Fade-Out operation processing.