Linux / AM4376： Mcasp output waveform problem

zhang huaiyang

Part Number: AM4376

Tool/software: Linux

Hi,TI:

From the hands of others took the project, the audio is not very understanding, linux operating system, the processor chip is am437x, audio chip is cs4344, from the serial port to catch some log, do not know if this information is useless:

[Davinci_mcasp_hw_params] rate = 44100, sbits = 16, slots = 2
Davinci-mcasp 48038000.mcasp: Sample-rate is off by 400 PPM
Davinci-mcasp 48038000.mcasp: sysclk_freq: 24000000 | bclk_freq: 1411200

The above should be some information about the frequency, using the i2s mode
The following is also attached to a problem with the waveform, the want to output smooth sine wave, the emergence of this situation I do not know how to get, thank you advise

over 9 years ago

0 Pavel Botev over 9 years ago

TI__Guru**** 170625 points

Hi Zhang,

Welcome to the e2e forum.

From what I understand, you are using AM437x custom board, right? Is that custom board based on EVM or SK or IDK?

Do you use PROCESSOR-SDK-LINUX-AM437X v03.03?

Regarding the waveform issue, you take that with oscilloscope, right? Which AM437x McASP pin is that?

Regards,
Pavel

0 zhang huaiyang over 9 years ago in reply to Pavel Botev

Prodigy 100 points

Hi Pavel,
I use the company's circuit board, the direct use of linux development environment, through the menuconfig configuration kernel. Yes, I am using an oscilloscope. Using the mcasp0, the following is am437x pin.
I would like to know what the possible cause of this waveform is. Since I am a beginner, do not understand this, I need a little direction. thank you very much.

MCASP0_ACLKX/PRU0_ENDAT0_CLK N24
MCASP0_FSX/PRU0_ENDAT0_OUT N22
MCASP0_AXR0/PRU0_ENDAT0_OUTEN H23

0 Pavel Botev over 9 years ago in reply to zhang huaiyang

TI__Guru**** 170625 points

Hi Zhang,

This might be hardware issue or software issue (wrong porting).

Do you observe this waveform on the AM437x MCASP0_AXR0 H23 pin?

You do not know if you are using PSDK, but do you know at least if you are using TI software and which kernel version? Can you provide me the whole boot up log for analysis?

Regards,
Pavel

0 zhang huaiyang over 9 years ago in reply to Pavel Botev

Prodigy 100 points

4278.am437x_mcasp.txt

Hi Pavel,

Thank you for your patience.

SDK may be ti-processor-sdk-linux-am437x-evm-03.01.00.06-Linux-x86-Install.bin,The attachment is boot log,AM437x MCASP0_AXR0 waveform of the H23 pin is as follows:

0 zhang huaiyang over 9 years ago in reply to Pavel Botev

Prodigy 100 points

Linux kernel version:
# uname -a
Linux buildroot 4.1.18-gbbe8cfc #2141 Wed May 3 02:50:04 PDT 2017 armv7l GNU/Linux

0 Pavel Botev over 9 years ago in reply to zhang huaiyang

TI__Guru**** 170625 points

huaiyang zhang said:
SDK may be ti-processor-sdk-linux-am437x-evm-03.01.00.06-Linux-x86-Install.bin

You have u-boot 2013.10, linux kernel 4.1.18, Buildroot, while PSDK 3.01 has u-boot 2016.05, linux kernel 4.4.19, Yocto. Thus it seems to me that you are not using PSDK 3.01. It seems to me that you are not using any of the available AM437x PSDKs.

Can you try with the latest AM437x TI PSDK 3.03?

If not, I can only provide you general suggestions:

- check if you have correct values in the pinmux registers

- check if you have setup your DTS files properly

- dump the McASP registers and check if you have the expected values there

- check with the scope all the McASP pins involved, check you have valid and expected signals there

See also if the below pointers will be in help:

http://processors.wiki.ti.com/index.php/Sitara_Linux_Audio_DAC_Example

http://processors.wiki.ti.com/index.php/Linux_Core_Audio_User's_Guide

Regards,
Pavel

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Linux / AM4376： Mcasp output waveform problem