CLKIN = MCLK or CLKIN = MCLK /2 ?

Anonymous

Other Parts Discussed in Thread: TLV320AIC23B

Converter Apps,

Thanks for the sample code and advices in previous posts. The DAC output could now work and I could hear 48KHz recorded audio played out from the DAC, with exactly the same pitch as they were recorded.

		proof
MCLK	18.4MHz	oscilloscope
Recording	48 KHz
CLKIN	MCLK/2	Register 8: 42	✓
	MCLK	Register 8: 02	✕ Higher pitch

This somehow confused me because TLV320AIC23B datasheet §3.3.2 describes tables in §3.3.2.1 as all based on CLKIN = MCLK, and I configured accordingly. However, the correct playback only happens when I choose CLKIN = MCLK /2.

Why could it be like this? Could you help me to figure out the reason?

Zheng

over 13 years ago

0 Converter Apps over 13 years ago

TI__Mastermind 28585 points

Hi Zheng,

I agree with your analysis. This doesn't look right. Perhaps there is an issue with the other clocks or some programming in the micro? You could try setting the AIC23B as the master and looking at LRCK with a scope to see what sample rate the AIC23B thinks it is running at in both conditions.

0 Anonymous over 13 years ago in reply to Converter Apps

Guru 17045 points

Converter Apps,

Thanks for confirmation. I will test on this some time later.

Zheng

0 Fang Jane over 13 years ago in reply to Converter Apps

Prodigy 50 points

Hi Converter Apps,

I encounter the same problem with Zheng, and now I set AIC23B as the master device and choice USB mode, but my headphone has only Left channel out, Right channel has noting out? I don't know why?

Fang

Audio

Audio forum

CLKIN = MCLK or CLKIN = MCLK /2 ?