Want to display graphic EQ

The Sharc and Blackfin DSPs can do FFTs, but the current generation of SigmaDSPs cannot. However, a full FFT really isn't necessary for your intended application.

To get a real-time frequency spectrum display, you can use a seven band level detector ( https://wiki.analog.com/resources/tools-software/sigmastudio/toolbox/leveldetectorslookuptables/sevenbandleveldetector ) or the level detector designer ( https://wiki.analog.com/resources/tools-software/sigmastudio/toolbox/leveldetectorslookuptables/leveldetectordesigner ) and use an external microcontroller to read back the levels of each frequency band to drive the LCD.

By the way, for future reference, a "Graphic EQ" is something that allows you to control the frequency response of a signal using bandpass filters spaced at regular intervals. What you are referring to is not a "Graphic EQ", but rather it is a "Spectrum Analyzer", which shows the frequency content of a signal.

I noticed that the detector can be read only by PC, through the path of USB - USBi - I2C of ADAU1701.

I hope I can read data by an MCU. But I can not find the protocol for transmitting data through I2C. Can it be open to customer?

Thanks,

Jackie

I know now --- I will use data capture function to read the data. Where can I find a demo code? The description for it is not enough to understanding clearly.

Hi Jackie:

Can you describe more your application. Some time ago we coded a led array block that was used to display frequency information through some of the GPIO controls of the 1701. It drived an Allegro IC for driving LEDs. I believe the code is not in SigmaStudio. Is this something similar to what you are trying to do?

Regards

Miguel

Hi Miguel

My product is a portable device, which is like a voice recorder. So LED array will consume quite large power. I must display everything on LCD.

I tried level detector today. But it will use much more program RAM which lead a overflow error when compiling it in SigmaStudio.

BR,

Jackie

发件人: engineerzone.admin@analog.com engineerzone.admin@analog.com 代表 MigCha

发送时间: 2013年4月14日 22:25

收件人: Tan Junchuan

主题: New message: "Want to display graphic EQ"

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Re: Want to display graphic EQ

created by MigCha <http://ez.analog.com/people/MigCha>; in SigmaDSP Processors and SigmaStudio Development Tool - View the full discussion <http://ez.analog.com/message/83510#83510>;

Dear Migcha

I studied data capture related topic in the ADAU1701 DS. I can not understand. Please help to explain:

1. Table 27. Data Capture Register Write Format: what is data_capture_adr[11:0]? Why is it 12 bit? What’s difference between it with progCount[10:0]( why is it 11 bit? )

2. It says progCount is generated by the SigmaStudio compiler. But I can not find it.

Thanks,

Jackie

发件人: engineerzone.admin@analog.com engineerzone.admin@analog.com 代表 MigCha

发送时间: 2013年4月14日 22:25

收件人: Tan Junchuan

主题: New message: "Want to display graphic EQ"

<http://ez.analog.com/index.jspa>; EngineerZone

Re: Want to display graphic EQ

created by MigCha <http://ez.analog.com/people/MigCha>; in SigmaDSP Processors and SigmaStudio Development Tool - View the full discussion <http://ez.analog.com/message/83510#83510>;

If you want to read back from the data capture registers, there is a sequence of steps you need to follow. The Capture Window in SigmaStudio doesn't show the full sequence of writes and reads in this case. It might be more useful to follow one of these tutorials:

https://ez.analog.com/message/7669

https://ez.analog.com/message/5209#5209

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EZ Admin