• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 18 subscribers
  • Views 1534 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TX517EVM: Generate 400Khz or 800Khz frequncy output with TX517EVM

Sajad Rahmdel
Expert 1705 points
Part Number: TX517EVM
Other Parts Discussed in Thread: TX517,

Hello,


We are still looking for a method to change the output frequency of TX517EVM to 400Khz or 800Khz. By default, the buttons on the board generate a signal between 5 MHz to 100MHz. This frequency is appropriate for medical applications. However, our application is sonar. Is there any method to change the frequency? Would it be possible to control this board externally?


We were thinking to generate PWM wave using our OMAP L138 LCDK, and then give this PWM wave as input to TX517EVM . Then TX517EVM would generate the output frequency based on the PWM that we gave TX517EVM as input. However, I don't know if it's possible or not. 

Any suggestions or advice is appreciated.

  • 0
    TI__Expert 4145 points
    Hi Sajad,

    Unfortunately, the TX517EVM is designed for control using the buttons on the board. If you want to use it for Sonar, you would either have to write new code to program the on-board FPGA or control the TX517 input pins directly.
    There are timing windows detailed in the datasheet that you have to meet to control the device properly. Also, since different input signals control different voltages, you would have to determine what pins to turn on/off at any given time based on your target output voltage.

    Sincerely,
    Olu
  • 0 in reply to Olu Sodipe
    Expert 1705 points
    As always, thank you Olu for your prompt and complete reply.
    Your answer helped a lot but the new information brought us new questions.

    1. As far as I know, TI doesn't provide the FPGA code used on this board. Do you know any tutorial on how to write this code? We just need to change the range of frequencies generated by the device.

    2. The other option, as you mentioned, is to control the TX517 input pins directly. It requires 12 PWM waves to make it work. Is there any way to generate a sign wave using only 4 PWMs with 1 clock? We could perhaps only generate signal on OUTA, so we wouldn't need all those PWMs?
  • 0 in reply to Sajad Rahmdel
    TI__Expert 4145 points
    Hi Sajad,

    I'ld actually recommend some kind of lookup table technique where you pick specific output voltages at specific times based on what signal shape you want at your output.

    Sincerely,
    Olu
  • 0 in reply to Olu Sodipe
    Expert 1705 points

    Olu,
    Thank you for the help.
    We've decided to design and use our own custom board because both solutions, namely, FPGA programming and TX517EVM control of pins seem too difficult to accomplish. On top of that, this board requires 12 different input voltages. My opinion is that this board definitely needs an upgrade. Reducing the number of input voltages and making it more flexible for customization would make this board even better.