Output problem of PCM1781

Vivien Staehle

Other Parts Discussed in Thread: PCM1781

Hello,

I want to convert audio data through the PCM1781 with the I2S bus, it is necessary to have the three clocks are synchronized, SCK (external oscillator: 24MHz), BCK (12 MHZ) and LRCK (192 kHz), and also DATA . I configured the liason I2S in Master mode and the PBCK clock, the problem is that I do not manage to have an analog output, my output is composed many of the different peaks like Dirac's distribution, and i can't have a correct sound like this.

Thank you for your help

over 9 years ago

0 Justin Bohr over 9 years ago

TI__Mastermind 27880 points

Hi Viven,

Could you clarify if your SCK and BCK were 24 MHz and 12 MHz exactly, or were they 24.576 MHz and 12.288 MHz? Also could you tell me what pin settings you are using?

Justin

0 Vivien Staehle over 9 years ago in reply to Justin Bohr

Prodigy 40 points

Hi justin,

They were approximatively around 24.576MHz and 12.288 MHz, I'm using Refclk1 as Master clock, it generate automatically the LRCK and BCK, i have also noticed that the data is not send in all periode of LRCK, and i found this very weird, i can see that data is sent once every two period of LRCK.

0 Justin Bohr over 9 years ago in reply to Vivien Staehle

TI__Mastermind 27880 points

Hi Viven,

This seems to be a problem with your audio source. There should be audio data on every LRCK period. Are you operating the PCM1781 in hardware or software mode. What are the settings you are using? Is there a known good I2S audio source you can test with?

Justin

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Output problem of PCM1781