Search found 48 matches

by cjf1699
Fri Jun 01, 2018 12:49 pm
Forum: Development Tools and Programming
Topic: How to decrease the sample rate properly on AN00162?
Replies: 4
Views: 3013

Re: How to decrease the sample rate properly on AN00162?

I changed the SAMPLE_FREQUENCY here, is there anything else that need to be modified? No, this is all you need - this directly changes i2s_config.mclk_bclk_ratio which is the key divider. The MCLK is the clock input and BCLK and LRCLK are generated by the I2S master. What is happening when it fails...
by cjf1699
Fri Jun 01, 2018 10:14 am
Forum: Development Tools and Programming
Topic: How to decrease the sample rate properly on AN00162?
Replies: 4
Views: 3013

Re: How to decrease the sample rate properly on AN00162?

There could be any number of reasons for this, but it could well be a timing issue. You can use timers to check you loop timing: timer t; unsigned t0, t1; t :> t0; //MY CODE HERE t :> t1; if (t1 - t0 > 1900) debug_printf("Argghh taken too long - more than 19 microseconds\n); Further i2s_master...
by cjf1699
Thu May 31, 2018 5:24 am
Forum: Development Tools and Programming
Topic: How to decrease the sample rate properly on AN00162?
Replies: 4
Views: 3013

How to decrease the sample rate properly on AN00162?

Hi everyone, I am developing an active noise cancellation headphone system on xCORE-200 Multichannel Audio platform, basing on the example: AN00162(Using the i2s library). And now I manage to reduce the noise of single frequencies(i.e. sine waves )from 100Hz - 1000Hz. However, when I change my noise...
by cjf1699
Mon May 28, 2018 8:29 am
Forum: Development Tools and Programming
Topic: Problem when realizing DSP algorithm:LMS on xCORE-200 MC Audio
Replies: 23
Views: 11060

Re: Problem when realizing DSP algorithm:LMS on xCORE-200 MC Audio

The problem with using Q31 is that you could get overflow when you multiply accumulate into a 64 bit register. Here is some explanatory text from ARM for their similar function (arm_fir_q31) that uses 32 bit input data and a 64 bit accumulator, with a 32 bit output: Scaling and Overflow Behavior: T...
by cjf1699
Mon May 07, 2018 8:55 am
Forum: Development Tools and Programming
Topic: Problem when realizing DSP algorithm:LMS on xCORE-200 MC Audio
Replies: 23
Views: 11060

Re: Problem when realizing DSP algorithm:LMS on xCORE-200 MC Audio

@cjf1699 If you're using the analogue inputs of the MC audio board, then the CS5368 data sheet shows that the conversion results do appear at the most significant end of each I2S data word. In other words it is logical to treat the data received from the I2S handler as Q31 format, and it would make...
by cjf1699
Mon May 07, 2018 8:42 am
Forum: Development Tools and Programming
Topic: Trouble on using DSP library
Replies: 0
Views: 4916

Trouble on using DSP library

Hi everyone, I am having trouble understanding something about the function: https://s9.postimg.cc/chv6bhhff/IE_7_R6_CE_59_Z_7_I_1_A_R.png I do understand what it is doing, while I don't know why it is called like this in the dsp_adaptive_lms function in the app_adaptive which is part of the AN00209...
by cjf1699
Tue May 01, 2018 10:59 am
Forum: Q&A
Topic: XUF216 Documentation on Port Usage with USB Clarification
Replies: 10
Views: 12143

Re: XUF216 Documentation on Port Usage with USB Clarificatio

Hi Kyle. The details on how to move the USB function onto Tile 1 is posted inside this example note: USB-HID-Class---Extended-on-xCORE-200-Explorer(1.1.2rc1).pdf https://www.xmos.com/published/an00182-usb-hid-class---extended-on-xcore-200-explorer?version=latest http://www.softio.com/xmos/xmos_xcor...
by cjf1699
Mon Apr 30, 2018 5:33 am
Forum: Development Tools and Programming
Topic: Problem when realizing DSP algorithm:LMS on xCORE-200 MC Audio
Replies: 23
Views: 11060

Re: Problem when realizing DSP algorithm:LMS on xCORE-200 MC Audio

The numbers you will have in the software raw from the MC audio ADC are Q31. Thank you! Sorry for late to answer. However,I found this in the i2s.h: https://s9.postimg.cc/wrne6a4zf/QMA_7_LP8_T_4_Z2_ISRK_Y.png Is that mean the converted data is stored in the top-24 bit? If I want to apply some dsp (...
by cjf1699
Thu Apr 19, 2018 4:43 am
Forum: Development Tools and Programming
Topic: Problem when realizing DSP algorithm:LMS on xCORE-200 MC Audio
Replies: 23
Views: 11060

Re: Problem when realizing DSP algorithm:LMS on xCORE-200 MC Audio

Yes..I mean comment out..

The problem is that I can't ensure the range of values of samples obtained by A/D, so I can't select a format rationally. According to the results of my printf, the values are so large regardless of the format...
by cjf1699
Wed Apr 18, 2018 9:06 am
Forum: Development Tools and Programming
Topic: Problem when realizing DSP algorithm:LMS on xCORE-200 MC Audio
Replies: 23
Views: 11060

Re: Problem when realizing DSP algorithm:LMS on xCORE-200 MC Audio

Thank you for your advice. I will have a try. As for if((F31(*error_sample))!=0){ The reason is that if I annotate this line , there was no wave in the xscope while with this line ,there was awful waves which I can't explain. And it's my fault, thank you for your correction. I found that perhaps my ...