PGA460-Q1: PGA460-Q1

Part Number: PGA460-Q1

We have the PGA460-Q1 Eval module and everything works perfectly for our application.  We are trying to watch the RX and TX serial data that the PC sends and receives to the Eval board.  We can clearly see the 55 and all RX and TX waveforms on the scope.  We use a simple 3.3V to RS-232 converter to watch the hex data on a serial monitors.  The data is random 00 FF 0C.... but we cannot determine the baud rate that the EVM is using.

I know that it autobauds on the 55 but our serial monitor cannot auto baud.

What is the Baud rate when the EVM does all of the register transfers and Commands?  115k, 9.6K... do not seem to work.

Thanks, Peter

33 Replies

  • Hi Peter,

    By default, the EVM baud rate is set to 115.2kBaud, but can be set to a lower value (down to 9.6kBaud).

    Can you provide an example UART string transmitted from you PC to the PGA460? Be sure that you are using two end/stop bits, no parity, and no flow control.

    Also, the PGA460 Software Development Guide [PGA460 Software Development Guide ] and PGA460 Energia Library and Code Example (Version 1.0.0) [http://www.ti.com/lit/zip/slac741] may be useful for you code development and debug.
    Akeem Whitehead
    Texas Instruments // ASC-SENSING-SSC // Applications Engineer
  • In reply to Akeem Whitehead:

    The PGA460 is working perfectly and the Eval software is excellent.  We can send and receive data directly to the PGA460 over Rx Tx from our product which is also MSP430 based.  Howevre, we want to occasionally use the eval software.

    The PGA460 Eval uses the piggyback TI MSP 430 Launchpad development board.  If we connect an RS-232 PC to 3.3V 115Kbaud adapter to the Tx and Rx pins on the PGA460 eval board (and bypass the TI Launchpad board), will the Eval software still work?  I assume that the TI Launchpad does no more than pass USB data directly the Tx Rx on the PGA460 so the eval software on the PC will still work if we connect the PC Com port directly up to the Tx Rx ??

    Thanks, Peter

  • In reply to peter mccormick:

    peter,

    I'm glad to hear your RS-232 PC to serial adapter is working with the PGA460. There shouldn't be any issue in using your own PC-to-Serial adapter in conjunction with the TI LaunchPad, as long as your adapter's serial pins do not load the Tx/Rx pins of the LaunchPad.

    The MSP430F5529 has an integrated USB PHY, so all the GUI PC-to-LaunchPad communication is independent from the PGA460 UART pins.

    Let me know if this works out for you! Worst case: you'll have to physically connect/disconnect the LaunchPad as needed.

    Akeem Whitehead
    Texas Instruments // ASC-SENSING-SSC // Applications Engineer
  • One more question:

    The PGA460 is excellent, however, can it also do the following?:

    1) Can the PGA evaluation software store the setup values for a particular piezo sensor so that we don't need to manually set the frequency, gains, thresholds every time we launch the software?  Something like a SAVE PGA .cfg file

    2) Can the user EEPROM be made to store All of the thresholds, gains, frequency and default power up values so that these don't need to be sent by the master computer every time it powers up?  It seems odd that many of the values are stored in EEPROM but not all of them so that the external computer still must load the values.  If yes, can this be done using the eval software?

    Thanks, Peter

  • In reply to peter mccormick:

    Peter,

    The PGA460 itself can save the setup value in its EEPROM space. For instance, if you optimize the frequency, pulse count, drive current, gains, etc., you can burn/program the device's EEPROM to save these values. If you do not wish to burn the values onto the EEPROM, then the GUI can save all register values (including volatile memory, which includes the thresholds) to a .TXT file. This .TXT file can then be loaded any time or to a different device. This is demonstrated in the the last video of the six part training series at: training.ti.com/ultrasonic-sensing-pga460-q1

    Whenever you are modifying the user registers values using the GUI, you are actually reading and writing from shadow registers, which are initially loaded with the values from EEPROM when the device is first powered. The only values that the user MUST write to upon every device power-/start-up or reset are the volatile threshold values. The other values you've mentioned should be burned to EEPROM, such that they default to the values required by the particular transducer and driver combination you are using.

    If you have not seen the mini video training series (collectively, less than an hour long), I recommend you view them for an overview of the EVM+GUI. Let me know if you have any additional questions afterwards.
    Akeem Whitehead
    Texas Instruments // ASC-SENSING-SSC // Applications Engineer
  • We used the Eval system and monitor the serial traffic.  Some of the responses do not make sense.
    Please clarify the ?? below.  Thanks, Peter

    55 c9 1c 1a    ask for frequency 1c=address
    40 32 8d 00     response from eval system
    40  ??  is this the address from the PGA with an address of 6?
    32=40khz frequency
    8d ??  what is the 8d in response
    00 ??
    -------------------
    WE SEND THIS COMMAND 5   I understand the other requests and setup commands
    55 ca 40 80 74     echo and retrieve 2 results
    55 c0 02 3d
    55 ca 40 00 f4
    55 c0 02 3d
    55 c5 3a
    55 ca 40 00 f4                      
    55 c9 4c e9
    55 c9 4d e8
    55 c9 1f 17   

    IT RESPONDS WITH THIS
    40 00 c0 ff ff 29 5c ff ff 79 00  //response 295f uS=1.828m  which is correct !
    40  ??  what is this ??
    00  ??
    c0  ??
    ff  ??
    ff  ??
    29 5c is 0295C hex is 1.828m ping which is correct
    ff is width ?
    ff is amplitude?  why is it so high?
    79 ?? 
    00 ??  

  • In reply to peter mccormick:

    Hi Peter,
    I am in-line responding to your questions by preceding my answer with [AW].

    55 c9 1c 1a ask for frequency 1c=address
    •40 32 8d 00 response from eval system
    •40 ?? is this the address from the PGA with an address of 6? [AW]No, this is the UART Diagnostic Field byte. The PGA460 always initiates its response with a diagnostic field byte to inform the user that the last command was received+processed successfully or not. A value of 0x40 indicates no error. See section 7.3.6.2.1.7 Diagnostic Field of the datasheet for details regarding this byte.
    •32=40khz frequency [AW] Correct.
    •8d ?? what is the 8d in response [AW] This is the UART checksum generated by the PGA460 device. Similarly to the diagnostic filed byte, the PGA460 always ends its UART transmission with a checksum to detect errors in the data. The checksum information is optional available for use by the master, but is always provided. In this example, 0x8D is the checksum value of { 0x40, 0x32 }.
    •00 ?? [AW] This is not part of the UART return, can be ignored.

    [AW] Please refer to Figure 28 of the datasheet to see the UART Register Read Response Example which explains this command above. Also see Table 3 - Interface Command List to understand what each byte for a response command means.

    -------------------
    WE SEND THIS COMMAND 5 I understand the other requests and setup commands
    55 ca 40 80 74 echo and retrieve 2 results
    55 c0 02 3d
    55 ca 40 00 f4
    55 c0 02 3d
    55 c5 3a
    55 ca 40 00 f4
    55 c9 4c e9
    55 c9 4d e8
    55 c9 1f 17

    IT RESPONDS WITH THIS
    40 00 c0 ff ff 29 5c ff ff 79 00 //response 295f uS=1.828m which is correct !
    40 ?? what is this ?? [AW] UART diagnostic byte as explained above.
    00 ?? [AW] Object 1 distance MSB
    c0 ?? [AW] Object 1 distance LSB
    ff ?? [AW] Object 1 width
    ff ?? [AW] Object 1 amplitude
    29 5c is 0295C hex is 1.828m ping which is correct [AW] Correct, Object 2 distance MSB,LSB
    ff is width ? [AW] Object 2 width
    ff is amplitude? why is it so high? [AW] Object 2 amplitude
    79 ?? [AW] PGA460 calculated checksum
    00 ?? [AW] null data, ignore

    [AW] The Object 2 amplitude and width is at 0xFF because it is likely the echo signal is saturated, and very wide. You need to reduce your TVG levels and/or Digital Gain multiplier to prevent saturation.
    Object 1 is likely triggering very early due to the threshold level and/or threshold glitch timer. See FAQs #5.2 & 5.6 from the Frequently Asked Questions (FAQ) and EVM Troubleshooting Guide (www.ti.com/.../slaa733.pdf) for details on how to mitigate this issue.

    Akeem Whitehead
    Texas Instruments // ASC-SENSING-SSC // Applications Engineer
  • In reply to Akeem Whitehead:

    Hello Akeem whitehead

    Can you please tell how to get a proper data values through bulk read from pga.
    Because if i read through bulk command i cannot read first 6 bytes properly. But after 6 bytes its coming exactly.
    Same problem happens for both eeprom bulk read command and ultrasonic measurement results command.
    I stuck here. I can read Echo data dump precisely but not ULTRASONIC MEAS RESULT(Object distance).
    please help me to solve this problem.

    Advance thanks....
  • In reply to Pradeep Kumar R:

    Hello Akeem whitehead

    Like data dump memory address(0x80) type is there any memory address for "ultrasonic meas result" so i can read byte by byte correctly.
  • In reply to Akeem Whitehead:

    I read the app note slaa733 to try to "ignore initial burst and decay..." on page 18 so that I can only look for 1 Object instead of seeing this initial crossing #1 on burst and finally my real object as #2.  I set the threshold and played with the gains but it still sees the threshold and a distance of .06m for object 1

    =set max Thresholds 248

    =set gain 1 to minimum of 248.    Also set tried with gain 1 to maximum but still same result.

    =Threshold Deglitch T is 120uS max which is not enough.

    There does not appear to be a way to make the threshold more than the amplitude of the initial burst so it always sees it cross the threshold at .06m.

    Is there a deglitch, gain, or threshold that I am not properly setting on the eval software?

    Peter  LassosPGAcreenshots.pdf