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CC8520 Pop noise

Edwin Ng
Intellectual 980 points

Other Parts Discussed in Thread: CC8520, PCM1773, MSP430F5438

Hi All,

 

Question 1

I build a prototype board which using CC8520+PCM1773 for DAC, I found that when CC8520 cannot receive the RF signal from TX side, the audio signal will stop with Pop noise, but Pop noise issue is not appear in CC85xxDK kit, any advise? as I know that CC8520 provide a mute function when the RF link broken, I would like to clarify that the mute function is provided by CC8520 stop I2S data out or CC8520 through I2C to send mute command to DAC? 

Question 2

How to fix the RF channel, because CC8520 is using frequency hopping, I want to measure the output power on my prototype board.

Question 3

Any reference source code of MSP430 when CC8520 work as slave, for example CC8520 provide AD0 & AD1, I want to switch between these two input without "Pure path wireless configurator"

Question 4

I'm prepare goto production now, each TX & RX board will be program to different product ID, but it another product which using CC8520 too, maybe Product ID are same, what would be happen?

Question 5

How to generate different Product ID under "Pure path wireless configurator"

Question 6

When go for production and perform testing, may I pre pair TX & RX board when download the FW from "Pure path wireless configurator" because I don't want to pair one by one in production line

BR

Edwin

  • 0
    Intellectual 980 points

    Dear Sir,

    May I clarify that how to perform mute function if using hardware control DAC eg. PCM1773, because it just provide a power down pin to drive the DAC to reset stage. CC8520 can output a I/O signal when RF link broken? 

    Because I have several customer their are using CC8520+PCM1773 for design in stage. if pop noise issue can't be reduce, they need to change to other DAC.

    BR

    Edwin

  • 0 in reply to Edwin Ng
    TI__Expert 6825 points

     Edwin,

    I sorry for the delayed response here. I will get back to you with the answers to the questions tomorrow!

  • 0
    TI__Expert 7160 points

    Hi Edwin,

    1. Are you sure you're hearing the pop noise when the TX side disapears? I find it more likely that you hear it when the TX side comes within range again and the RX device re-joins. Can you confirm? When the RX side looses connection with the TX side the RX CC85xx mutes all audio channels by outputting zeros on the ADx line.

    2. I will post a small tool on the forum that enables you to patch one EHIF command to an existing production test image, meaning that you could for example run RFT_TXTST_CW (see family user's guide) immediately after power up. Another way to fix the RF channel is to use an external MCU as SPI host and run RFT_TXTST_CW.

    3. Have a look at this post for a small EHIF example using the MSP430F5438: http://e2e.ti.com/support/low_power_rf/f/382/t/115370.aspx

    4. When you write: "...but it another product which using CC8520 too..." I guess you mean another product from another company/manufacturer? You have the possibility to filter on manufacturer ID as well, so if you take the device ID from one of the CC85xx devices you possess, and use this as your manuacturer ID you are guarantied that your manufacturer ID is globally unique.

    5. The Product ID is set freely in the configurator. Simply type it in the Product ID field in the Device Identification panel.

    6. To pre-pair in production you must know the master's device ID. This is obtained either by the EHIF command DI_GET_DEVICE_INFO or by connecting the CC Debugger to the master and view the device ID in the Flash Programming panel. Then you have to store this device ID in the slave's non-volatile flash memory. This is done either by typing it in the Default network ID field in the Radio panel in the configurator or use the EHIF command NVS_SET_DATA after flashing.


    -Kristoffer

  • 0 in reply to Kristoffer S
    Intellectual 980 points

    Kristoffer,

    1. I sure, because when I hear the pop noise, the pairing LED turn off and then flashing. that means TX and RX disconnected. if you just put zero to ADx line the DAC will goto zero suddenly, so pop noise will appear. any explain to design CC8520+DAC without I2C control, because PCM1773 is HW control no I2C control, that mean I can't mute before ADx goto zero

    BR

    Edwin

  • 0 in reply to Edwin Ng
    TI__Expert 7160 points

    Hi Edwin,

    That's strange. Right before we mute i.e. zeroes on the ADx pin, we do a graceful mute over the last 32 samples so you shouldn't get a pop noise when you loose the master. Also, the output of your DAC will not go to zero, you will still have your DC component, but AC-wise it will be zero. Pop noise normally appears when you have a step in your DC component. Would it be possible that you posted a recording of the pop noise? A wav-file etc..

    Have you written a driver for your DAC? In the newest configurator we support the ability to write drivers for whatever audio device you want (I2C or pin controlled or both). We support up to 4 control pins in addition to I2C. You should have reset as one of these pins and pull this reset pin when you loose the network. When the slave looses it's network it goes down into the INACTIVE state (it rushes through the LOW-POWER state as well). How to write your own audio device driver is well described in the configurator's help menu in the chapter "Audio Device Definition Files". Also have a look at the Audio Device Customization panel in the configurator. I recomend that you open the CC85XXDK Preloaded Demo project from the start page, enable "Custom setup" in the Audio Interface panel for the slave, and hen click the Audio Customization panel. Further hit the "Reset all" button and look at the different configuration sequences e.g. OFF to INACTIVE, INACTIVE to LOW POWER etc. You should also open the file aic3101.ppwadd located in <Install folder>\audio_devices and study what have been done in order to enable the configuration of a reset pin.

    By the way, I have now placed the small tool on the forum. This will alow you to fix the frequency in order to do RF measurements. Have a look here: http://e2e.ti.com/support/low_power_rf/f/382/t/115633.aspx

    -Kristoffer