AIC3254 digital microphone on Evm

Hi, Amir,

Welcome to E2E and thank you for your interest in our products.

Could you provide the entire register configuration? Page 0 / Register 81 is used to configure left/right ADC for digital microphone. Did you configure this register?

Best regards,
Luis Fernando Rodríguez S.

Hi Luis,

Yes,

I tried to configure it to Din (bit 5-4= 10) and to GPIO (bit 5-4 = 00)

Still white noise.

TI_PAGE_0_REGISTERS.xls

Hi, Amir,

The digital microphone can only be used with MISO/GPIO as ADC_MOD_CLK and DIN/SCLK/GPIO as microphone data. DIN seems to be well configured, but I didn't obtained a clock signal on MISO/GPIO output. Could you try configuring register 0x34 as 0x28, please? It enabled the GPIO output to be used as ADC_MOD_CLK.

Best regards,
Luis Fernando Rodríguez S.

Hi Luis,

I will try changing this register.

(Although I saw with scope clk on GPIO pin)

The digital mic is outputting PDM.

Need to configure the codec for this data ?

How to connect directly digital mic to speakers/headphones ?

Thanks,

Amir

Hi, Amir,

Once the clock pin and data pin are configured to receive data from the digital microphone, the left/right channel must be configured for digital microphone (Page 0/ Register 81).

Then, in order to route the digital mic to speakers/headphone, it is necessary to activate the digital loopback mode (stereo ADC output is routed to stereo DAC input with page 0 / register 29). With this function, the data from the digital microphone is received with the DAC. Then, it would be necessary to configure the speakers/headphones to use the DAC outputs.

I hope this helps you. Please let me know if you have more questions or comments.

Best regards,
Luis Fernando Rodríguez S.

Hi Luis,

Probably the digital mic is not working correctly since I think, that the noise I am hearing is the data I see on the data line.

I will try to replace a digital mic.

One more question,

Are all functions of manipulating (gain and filter) for the analog acquisition from an analog microphone are available for acquiring data from digital microphone ?

Can I use gain and filter function on digital mic the same as I used in the analog mic ?

Thanks,

Amir

Hi, Amir,

Figure 2-23. Digital Microphone in TLV320AIC3254 explains how the digital microphone is connected internally. So, all the blocks before the ADC block are not applied to the digital microphone data. However, all the signal processing blocks can be applied to the digital microphone data.

Please let me know if the problem persists after replace the mic.

Best regards,
Luis Fernando Rodríguez S.

Hi Luis,

The mic isn't the problem.

I replaced it.

Can you tell me if the AIC3254 supports PDM interface ?

Hi, Amir,

I have been looking for more information. The AIC3254 supports PDM interface, so it should be a problem on the register configuration.

Here I have an example script for the TLV320ADC3101. It is not the same device, but it could be useful for you to compare your digital mic configuration with it: e2e.ti.com/.../55084.

Best regards,
Luis Fernando Rodríguez S.

Hi,

Link is broken.
1) Can you send it to me?
Can you elaborate what is the process ?

2) where do you see that PDM is supported ?
I cant find it .

3) Another question - can I configure pins inside the pure path (SCLK as digital mic etc..)
I want eventually to play with purepath

4) Final question - where can I find good references for this codecs. I want to implement audio system with filter on specific frequencies.

Thanks,
Amir

Hi Luis,

The link is broken,

Can you send me the reference again ?

Hi, Amir,

This is the example script. It should be adapted to the AIC3254 registers:

###############################################
# Software Reset
###############################################
#
# Select Page 0
w 30 00 00
#
# Initialize the device through software reset
w 30 01 01
#
# Delay 100ms
d 100
###############################################

###############################################
# Clock and Interface Settings
# ---------------------------------------------
# The codec receives: MCLK = 4.096 MHz,
# BLCK = 512 kHz, WCLK = 8 kHz
###############################################
#
# Select Page 0
w 30 00 00
#
# PLL_clkin = MCLK, codec_clkin = PLL_CLK,
# PLL on, P=1, R=1, J=24, D=0000
w 30 04 03 91 18 00 00
#
# NADC = 12, MADC = 8, dividers powered on
w 30 12 8C 88
#
# AOSR = 128
w 30 14 80
#
# DMCLK and DMIN used for DIG MIC
w 30 33 28 04
#
###############################################

###############################################
# Signal Processing Settings
###############################################
#
# Select Page 0
w 30 00 00
#
# Set the ADC Mode to PRB_P1 (default)
w 30 3d 01
#
###############################################

###############################################
# Recording Setup
###############################################
#
# Select Page 0
w 30 00 00
#
# Left ADC Vol = 0dB
w 30 53 00
#
# Right ADC Vol = 0dB
w 30 54 00
#
# Power-up Left ADC and Right ADC
# DIG MIC enabled for left and right ADCs
w 30 51 cc
#
# Unmute Left and Right ADC Channels (Gain = 0dB)
w 30 52 00
#
###############################################

Our codecs digital microphones support PDM as the following E2E thread explains: https://e2e.ti.com/support/data_converters/audio_converters/f/64/p/323342/1128795#1128795. 

Additionally, the codec can be configured by PurePath Studio. The framework that you select has a SystemSetting Code property which can be selected to change the register configuration. You just need to click on the framework, then go to the properties window and select the SystemSettings Code property. It will appear a [...] button. It will provide all the register configuration that can be modified.

For any additional information, please take a look of the AIC3254 technical documents section: http://www.ti.com/product/TLV320AIC3254/technicaldocuments.

I hope this helps you. Please let me know if you have more questions or comments.

Best regards,
Luis Fernando Rodríguez S.