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PGA460-Q1: Unwanted data occured at the end of DataDump

Beatrice Lung
Prodigy 10 points
Part Number: PGA460-Q1
Other Parts Discussed in Thread: PGA460, BOOSTXL-PGA460

Tool/software:

Dear Madam/Sir, 

I am seeking for help to get rid of the unwanted data from DataDump as highlighted in yellow below <130,118,172,244,144,35,227,163,22,80,138,231,43,114,147,197,240,102,56,45,229,25,85,253,45,176,26,75,237>. 

I used MCU with Arm Core M4  to write the code, use UART1 for  communication (baud rate: 9600, no parity bit, 8 data bits, 2 stop bits) with PGA460-Q1, and use another UART2 to print the debug data. 

I followed the source code from www.ti.com/lit/zip/slac741

1) initThresholds - Do not find issue. I also printed the register data from 0x0~0x2b, 0x40~0x4d, 0x5f~0x7f for verification after PGA460 Initialization and configuration. 

2) runDiagnostics - Do not find issue. 

3.1) runEchoDataDump -   Unwanted data <130,118,172,244,144,35,227,163,22,80,138,231,43,114,147,197,240,102,56,45,229,25,85,253,45,176,26,75,237>  at the end of the DataDump has occurred. It seems not to be noise because I have verified the checksum from DataDump[0]  to DataDump[128] and it is as same as that in DataDump[129] which is 221.    
3.2) pullEchoDataDump

4.1)ultrasonicCmd - Do not find issue.

4.2)pullUltrasonicMeasResult - Do not find issue. The object distance of  about 0.6 meters is correct. 

Using another UART2 to print the debug data as follows: 

1.initThresholds-buf16:55,10,88,88,88,88,88,88,84,21,8,42,10,80,80,80,80,0,88,88,88,88,88,88,84,21,8,42,10,80,80,80,80,0,
Verify register data from address 0x0 ~ 0x2b: 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,88,88,88,82,8,20,80,60,8c,a0,10,10,55,55,19,33,fe,7c,f,0,0,9,9,62,
Verify register data from address 0x40 ~ 0x4d: 0,8b,4d,f3,72,6,47,7c,d3,1,97,0,80,0,
Verify register data from address 0x5f ~ 0x7f: 88,88,88,88,88,88,84,21,8,42,10,80,80,80,80,0,88,88,88,88,88,88,84,21,8,42,10,80,80,80,80,0,28,
2.1.runDiagnostics-diagMeaResult:40,40,40,40,40,40,40,40,
System Diagnostics - Frequency (kHz): 60.606061
System Diagnostics - Decay Period (us): 1056.000000
2.2.runDiagnostics-tempNoiseMeasResult:40,77,7,41,0,0,
System Diagnostics - Die Temperature (C): 36.666667
2.2.runDiagnostics-tempNoiseMeasResult:41,77,7,40,0,0,
System Diagnostics - Noise Level: 7.000000
Retrieving echo data dump profile. Wait...

4.2.pullEchoDataDumpBulk
64,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,119,45,15,12,12,11,11,9,8,8,8,8,7,5,4,7,7,7,8,8,7,8,8,7,5,6,7,5,7,8,9,11,14,15,9,18,41,85,137,172,190,194,191,170,150,122,77,33,18,19,14,9,8,8,6,8,8,7,9,7,7,7,6,6,6,7,8,8,8,9,8,7,8,6,7,9,9,5,7,7,130,118,172,244,144,35,227,163,22,80,138,231,43,114,147,197,240,102,56,45,229,25,85,253,45,176,26,75,237,221,
Verify checksum: 221

4.3.pullEchoDataDumpBulk-bulkString:255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,119,45,15,12,12,11,11,9,8,8,8,8,7,5,4,7,7,7,8,8,7,8,8,7,5,6,7,5,7,8,9,11,14,15,9,18,41,85,137,172,190,194,191,170,150,122,77,33,18,19,14,9,8,8,6,8,8,7,9,7,7,7,6,6,6,7,8,8,8,9,8,7,8,6,7,9,9,5,7,7,130,118,172,244,144,35,227,163,22,80,138,231,43,114,147,197,240,102,56,45,229,25,85,253,45,176,26,75,237,
6.1.ultraMeasResult - obj1:41,d,b1,61,c4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
objReturn: 0.600936
P1 Obj1 Distance (m): 0.600936

6.1.ultraMeasResult - obj1:41,d,bc,5c,b9,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
objReturn: 0.602994
P1 Obj1 Distance (m): 0.602994

6.1.ultraMeasResult - obj1:41,d,b5,5d,be,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
objReturn: 0.601622
P1 Obj1 Distance (m): 0.601622

Could you please help? 

Thank you. 

Regards,

BL

  • 0
    TI__Mastermind 22180 points

    Hello Beatrice,

    Thanks for posting to the sensors forum! I am just trying to understand why the last portion of the data is not needed?

    Have you tried changing your record length time? Perhaps you are recording a longer period than necessary an are catching reflections from an unwanted target.

    Best,

    Isaac

  • 0 in reply to Isaac Lara
    Prodigy 10 points

    Hello Issa, 

    The register (REC_LENGTH) data from address 0x22 has been been verified to be 0x19 (as above). P1_REC is 8.192 ms , while P2_REC is 40.96ms. The unwanted data occurred at 6.4ms ~8.192ms. 

    Beforehand, I had checked the following:

    1a)  Use BOOSTXL-PGA460 board

    1b) + same PGA460-Q1 senor module assembled in the same fixture (pointing to the only object 1 at 0.6 meter apart)

    1c) + same PGA460 Initialization and configuration verified  by checking Memory Map of GUI downloaded from  https://www.ti.com/tool/download/SLAC739/01.00.00.0T

    1d)  Result from DataDump: Correct, no unwanted data. 

     

    2a)  Use Arm core M4 interface board, UART1 for  communication (baud rate: 9600, no parity bit, 8 data bits, 2 stop bits) with PGA460-Q1, and use another UART2 to print the debug data.

    2b) + same PGA460-Q1 senor module assembled in the same fixture (pointing to the only object 1 at 0.6 meter apart)

    2c) + same PGA460 Initialization and configuration verified by debug printing register data from 0x0~0x2b, 0x40~0x4d, 0x5f~0x7f.

    2d) Result from DataDump: Not ok, unwanted data occurred at the end of DataDump as highlighted above which I need your help for root cause and solution.  

    Thank you.

    Regards,

    BL

  • 0 in reply to Beatrice Lung
    TI__Mastermind 22180 points

    Hello Beatrice,

    Thanks for the info. The data seems far too high for it to be noise so it looks like you may be getting reflections from other items behind your target. 

    Do you have a key are you are just trying to target? For example 0.5m-1m?

    If this is the case you could tune your settings to optimize detection for your area of interest.

    Some items to check:

    • TVG gain settings-The TVG on the PGA460 allows you to control the gain in different times all in reference to the excitation pulse.
    • Threshold settings- Used for UMR measurements
    • Digital gain start threshold settings- sets the time when the digital gain is activated

    For example if your range is max 1m detection, then after the 1m time has elapsed you can decrease the TVG gain, increase the threshold required to trigger a measurement, and change the SR and LR digital gain settings and this should help you ignore items that happen after 5.8ms.

    Best,

    Isaac