Hi,
1. I am trying to set a 4th-order notch filter using Pure Path using the cascaded biquads block.
I was able to make this filter work for primary AIS interface of tlv320aic3254 chip. Attched below are Mag vs frequency responses of
recorded audio on primary interface.
Without Notch Filter :
With Notch Filter at 4.2Khz:
2. I have trouble getting this filter work for the Secondary AIS interface of tlv320aic3254.
I do get audio on this Interface, but the frequency response shows that the filtering action has not taken place !!!
i.e. I don't see a dip at 4.2Khz in the Mag vs Frequency response.
3. I have no clue as what is going wrong.
I have attached the Pure Path text scripts (which I have modified to suit my hardware) using for primary and secondary AIS interface.
5684.Primary_interface_PURE_PATH.txt
4721.Secondary_Interface_PURE_PATH.txt
Can someone please help in reviewing this script, particularly for the secondary interface.
I am not sure above scripts are sufficient to debug the problem, please do inform if any further details are needed.
Thanks,
Brontok :)
Has anybody been able to use miniDSP and get filtered audio on Secondary Interface ?
If yes then please share the register settings/ script used to do so, it will be of great help.
Brontok :(
Hi, Brontok,
We are looking into your question.
-d2
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Don Dapkus
Audio Applications Engineering Manager
Dallas, TX USA
Hi,This time I have tried to avoid the miniDSP and use the ADC processing block 2 instead, which offers 5 cascaded biquads. I made use of Biquad A and Biquad B to form a 4th order notch filter at 4300Hz, and used Biquad Coefficient calculator by TI. Again here, I observe, the filtering action happening only for primary interface and not on secondary interface. It seems to me that I am not properly configuring the Secondary interface.Please can you review the script below, No miniDSP involved here, ADC processing block 2 is used :3632.audiochip_secondary_notch4300.txt // Notch filter for 4300Hz, 48Khz sampling frequency, Master_clock12.288 Mhz, Word_clock = 48Khz, bit_clock = 3Mhz biquad_coefficients = 0x7E 0x58 0x95 0x00 0x95 0x25 0x4A 0x00 0x7E 0x58 0x95 0x00 0x6A 0xDA 0xB6 0x00 0x83 0x4E 0xD5 // Software Reset w 0x30 0x00 0x00 // Select PAGE 0 w 0x30 0x01 0x01 // Initializ Device through software reset // Power Supply Configuration w 0x30 0x00 0x01 // Select PAGE 1 w 0x30 0x02 0x09 // Power up ALDO w 0x30 0x01 0x08 // Disable Weak Avdd & connect it to Dvdd w 0x30 0x02 0x01 // Keep ALDO Powered enable master analog power control w 0x30 0x47 0x32 // Set input power-up to 3.1 msec w 0x30 0x7b 0x01 // Set REF chargup to 40 msec
// Clock Configuration w 0x30 0x00 0x00 // Select PAGE 0 w 0x30 0x04 0x0f // pll_input = Din & Codec_Clk = pll_clk w 0x30 0x06 0x07 // J = 7 w 0x30 0x05 0x91 // P = R = 1 & Power-up w 0x30 0x0b 0x02 // NDAC = 2 & Power-down w 0x30 0x0c 0x07 // MDAC = 7 & Power-down w 0x30 0x12 0x82 // NADC = 2 & Power-up w 0x30 0x13 0x87 // MADC = 7 & Power-up // Secondary Interface Configuration w 0x30 0x00 0x00 // Select PAGE 0 w 0x30 0x34 0x04 // Seconday Wclk = MFP5 w 0x30 0x37 0x10 // Secondary Output = MFP4 w 0x30 0x1f 0x20 // Secondary MUX for Wclk = GPIO/MFP5 & Secondary MUX for Bclk = SCLK/MFP3 w 0x30 0x20 0x0e // AIS will use secondary interface settings w 0x30 0x21 0x3d // Secondary Data output from Serial Interface w 0x30 0x1d 0x04 // Force AIS output the respective secondary clks w 0x30 0x1b 0x20 // 24-Bit format on I2S w 0x30 0x00 0x01 // Select PAGE 1 w 0x30 0x0a 0x7b // 0.75 V common mode // ADC Configuration w 0x30 0x00 0x00 // Select PAGE 0 w 0x30 0x3d 0x02 // Processing block 2 for ADC IIR with flat response
// 4TH Order Notch w 0x30 0x00 0x08 // Select PAGE 8 w 0x30 0x24 biquad_coefficients 19 bytes w 0x30 0x38 biquad_coefficients 19 bytes w 0x30 0x00 0x09 // Select PAGE 9 w 0x30 0x2c biquad_coefficients 19 bytes w 0x30 0x40 biquad_coefficients 19 bytes
w 0x30 0x00 0x01 // Select PAGE 1 w 0x30 0x3d 0x64 // ADC PowerTuneMode 3 w 0x30 0x33 0x58 // Mic Bias 1.45 V w 0x30 0x34 0x10 // IN2L to positive of LPGA w 0x30 0x36 0x10 w 0x30 0x37 0x04 // IN3R to positive of RPGA w 0x30 0x39 0x04 w 0x30 0x3b 0x2c // unmute LPGA with gain of 22dB w 0x30 0x3c 0x2c // unmute RPGA with gain of 22dB // Power up ADC & DAC w 0x30 0x00 0x00 // Select PAGE 0 w 0x30 0x51 0xc0 // Power up LADC and RADC w 0x30 0x52 0x00 // Unmute LADC & RADC gain is 0dbThanks,
Shriyash Chougule
Hi Shriyash,
How are you measuring the signal exactly? We can discuss this offline if you'd like. I'll send you a friend request
Regards,Dan Katz