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AWR2243: CQ data read and LVDS CRC

Part Number: AWR2243

Hello,

    I have some  questions about CQ and LVDS CRC.

1.   What is the relationship between the value of CQ1 and the value in AWR_RF_DFE_STATISTICS_REPORT_SB?  Can these two values be converted to each other? 

2.  CQ1 is the power value of signal and image. Slice number must be set as singular or both singular and even? Because I see the Primary slice =(N+1)/2, secondary slice= (N-1)/2, if N is even,  What is the value of slice number? The length of CQ1 and CQ2 are fixed at 32 Bytes. When I set my slice to 16, I see an effective value of 8 bytes, corresponding to 4 slices. For example, one byte value is 0XAF, the corresponding power is 175* (-0.5dBm) =-87.5dBm. But when I set my slice to 15, I only see an effective value of 6 bytes of RX0, corresponding to 3 slices, and then all zeros; I can see an effective value of 8 bytes in nRX1/2/3. 

  Why is it a fixed length? I understand there should be a total of slice*2 bytes.  

  What means are those "effective values" ?  Is the power calculation correct?

 

3.  I can configure LVDS CRC enable , but I don't know where I can see CRC data. Is it added at the end of normal LVDS to transmit to the external host or just a internal data in chip between ADC buffer and CBUFF that user can't read ?  In the AWR16XX and AWR22xx data path document, I see some description about CRC register, but I don't know how use these registers. Actually I think these registers are not configurable. Can you tell me how I can check the LVDS' correction? Beacause I put the RADAR into a High and low temperature box,which  six sides are metal inside, my LVDS data is wrong including CQ's configuration value for "N". When I decrease the power of TX or the gain of RX, LVDS data return to normal. I think some scenarios can trigger the LVDS data wrong, can you let me know this infomation and how to deal it?

In addition, I think that theory does not agree with practice about LVDS CRC. Maybe we lack the latest documentation? 

  • Hi,

    Thank you for your query.

    Let us check this internally and get back by mid next week.

    .

    Regards,

    Jitendra

  • Hi,

       Is there any information you can give me?

  • Hi,

    Please find my comments below.

    1.   What is the relationship between the value of CQ1 and the value in AWR_RF_DFE_STATISTICS_REPORT_SB?  Can these two values be converted to each other? 

    Comment) You can consider them to be independent. It is not suggested to interchange/convert between these values.

    2.  CQ1 is the power value of signal and image. Slice number must be set as singular or both singular and even? Because I see the Primary slice =(N+1)/2, secondary slice= (N-1)/2, if N is even,  What is the value of slice number? The length of CQ1 and CQ2 are fixed at 32 Bytes. When I set my slice to 16, I see an effective value of 8 bytes, corresponding to 4 slices. For example, one byte value is 0XAF, the corresponding power is 175* (-0.5dBm) =-87.5dBm. But when I set my slice to 15, I only see an effective value of 6 bytes of RX0, corresponding to 3 slices, and then all zeros; I can see an effective value of 8 bytes in nRX1/2/3. 

      Why is it a fixed length? I understand there should be a total of slice*2 bytes.  

      What means are those "effective values" ?  Is the power calculation correct?

    Please refer to the ICD for more details on this. I am adding a snap below form the ICD. 

    Here the range and valid numbers for the CQ1 monitor are specified. You can pick any valid value. 

    Also do note that CQ1 data is to be used primarily to identify excessive reflections and interference in the environment. So, the user should be performing a relative thresholding on the CQ1 data to identify those samples and then repair/reject the samples. A relative approach will be better than to convert it to absolute power. 

    Also ensure that you follow all the preconditions as mentioned in the ICD for this monitoring. 

    3.  I can configure LVDS CRC enable , but I don't know where I can see CRC data. Is it added at the end of normal LVDS to transmit to the external host or just a internal data in chip between ADC buffer and CBUFF that user can't read ?  In the AWR16XX and AWR22xx data path document, I see some description about CRC register, but I don't know how use these registers. Actually I think these registers are not configurable. Can you tell me how I can check the LVDS' correction? Beacause I put the RADAR into a High and low temperature box,which  six sides are metal inside, my LVDS data is wrong including CQ's configuration value for "N". When I decrease the power of TX or the gain of RX, LVDS data return to normal. I think some scenarios can trigger the LVDS data wrong, can you let me know this infomation and how to deal it?

    In the application note itself as below

    It mentions that CRC can be enabled at two places. One is the transfer of data form ADC buffer to CBUFF which is an internal buffer for LVDS transfer. Here you will not be able to check the appended packet as the data flow is completely internal to the device. 

    Second is data integrity check on the lanes. For LVDS lanes the registers are mentioned in the app note itself for enabling this. Figure 26 also shows the CRC packet getting appended over the lanes if the CRC is enabled. 

    You can check the DFP examples for AWR2243 to check our example configurations of the LVDS lanes. That will assist in your configuration. Snap is added below you can check the DFP folder for more details.

    Thanks,

    Pradipta.

  • Hi,

      I'm sorry for the late reply.

      About CQ data's config, I had refered to  ICD but I still have some questions.  

       1) Slice number must be set as singular or both singular and even? If I set NUM_SLICES= 16, is  primary slices  9 or 8 ?

      

     2) My data format is 16-bit mode, if num_slice=17, I should spy the bit7-0 is 17, and the total number of bytes is (17+1)*2=36 bytes. But I can't see what I want to see.  As I said earlier, I see a fixed length data for different configure of "N".

    About LVDS CRC, I found this instruction as following, but I'm still not able to how to carry out. Because I don't find register of CFG_LVDS_GEN_0  and e CFG_CMD_HSVAL and CFG_CMD_HEVAL.   Can you tell me in detail how to operate it?

      

       

  • Hi,

    Please find my comments below.

     Slice number must be set as singular or both singular and even? If I set NUM_SLICES= 16, is  primary slices  9 or 8 ?

    There is no restriction on the number of slices. It should be in the valid range. That is the only condition. If slices are even number, then the primary and secondary slices will be equal. 

    My data format is 16-bit mode, if num_slice=17, I should spy the bit7-0 is 17, and the total number of bytes is (17+1)*2=36 bytes. But I can't see what I want to see.  As I said earlier, I see a fixed length data for different configure of "N".

    Check your slice duration values for any discrepancies. If they are ok and as per the calculations in the ICD you should see the correct CQ data. We used the AWR2243 device on the bench with mmwave studio and we were able to obtain the correct CQ data. Please try this experiment at your end and let us know if you are not able to capture the data and obtain the CP/CQ values. 

    About LVDS CRC, I found this instruction as following, but I'm still not able to how to carry out. Because I don't find register of CFG_LVDS_GEN_0  and e CFG_CMD_HSVAL and CFG_CMD_HEVAL.   Can you tell me in detail how to operate it?

    Refer to the API AWR_DEV_LVDS_CFG_SET_SB in the ICD for AWR2243. This will provide you the option to enable or disable the CRC. As a user you can only use the SPI communication and send API commands to the AWR2243. Hence for all the configurations mostly you will have an API. As a user you can write registers in AWR2243. 

    Thanks,

    Pradipta.

  • Thank you. I have obtained the correct CQ data.