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TUSS4440: continuous pulses configuration

Kailyn Chen
Genius 9560 points
Part Number: TUSS4440

Hello,

According to the datasheet, when the IO_mode is configured IO mode 0 and 1,the pulsed numbers are defined by the BURST_PULSE. 

For example, if BURST_PULSE is configured 0X3F, it could send 63 pulses.

And the datasheet also describes that for IO mode 1and 0, if the BURST_PULSE=0, it could generate continuous burst pulses. But actually, when BURST_PULSE=0, it couldn't send pulse, and the PULSE_NUM_FLT status is set to 1. Please help to confirm if BURST_PULSE=0 could generate continuous burst pulses. 

Best regards

Kailyn

  • 0
    TI__Mastermind 23045 points

    Hello Kailyn,

    Thanks for posting to the sensors forum!

    That is correct, if the user needs to continuously needs to burst they can configure the BURST_PULSE = 0. They still need to provide the necessary signal at the IO pins in order to generate the pulses, if they just need a high count and not continuous they can also set the pulse count on the BURST_PULSE register. The TUSS44x0 GUI does not have the continuous burst function enabled but it does allow them to configure 0x3F to the BURST_PULSE register, here is a scope capture when using ox3F below:

    Best,

    Isaac

  • 0 in reply to Isaac Lara
    TI__Genius 9560 points

    Hi  Isaac,

    Thank you very much for your reply.  

     According to the test result,  BURST_PULSE = 0 ,and IO pins are referred to  IO MODE=1 mode to provide signals, but there is no pulse generation and the status bit PULSE_NUM_FLT =1. 

    Best regards

    kailyn

  • 0 in reply to Kailyn Chen
    TI__Mastermind 23045 points

    Hello Kailyn,

    Can the customer provide a capture of what their IO signals looks like when attempting the continuous burst?

    The PULSE_NUM_FLT indicator can occur due to a couple of factors, such as the pulse duration, missing amount of pulses, loss of external clock, or the signal on the IOx pins is stuck in a state.

    Best,

    Isaac

  • 0 in reply to Isaac Lara
    TI__Genius 9560 points

    Hi Isaac,

     The whole curve is as following, IO1 is yellow, IO2 is green.

    The start curve is as this:

    The end curve is as this:

    And the same signal of IO1 and IO2 pin, has tried the IO_MODE=1 and IO_MODE=0,but when BURST_PULSE=0,there is no pulse generation, so I am wondering why is it ? 

    Best regards

    kailyn

  • 0 in reply to Kailyn Chen
    TI__Mastermind 23045 points

    Hello Kaylin,

    Thanks for the info, I tried setting this up on the EVM board but I was not able to see a continuous burst either. I tried both IO_MODE=0 & 1 with the same results.

    I could see the pulses changing as I changed the values on BURST_PULSE register but when I would get to BURST_PULSE= 0 I couldnt see a pulse.

    Let me check internally with the team to see if there is any more info on this feature. I will get back to you once I have more info.

    Best,

    Isaac

  • 0 in reply to Isaac Lara
    TI__Genius 9560 points

    Hi Isaac,

    Thank you very much. Waiting for your information.

    Best regards

    kailyn

  • +1 in reply to Kailyn Chen
    TI__Mastermind 23045 points

    Hello Kailyn,

    I am still waiting for feedback on the BURST_PULSE = 0 for IO_MODE 0 and 1, but the digital designer is currently out of office so it might be a bit before we get more info. I did achieve continuous burst in IO_MODE = 2, since this actually does not take into account the value in the BURST_PULSE register.

    I included a  scope capture below, this was taken using a 5 s/div so I was bursting for about 40 seconds here.

    Although I will note that when doing continuous bursts the voltage to the transducer was reduced when compared to doing a smaller burst with fewer pulses. This is due to a capacitor that needs to be charged on the VDRV pin. I am not sure if the customers application but if the continuous burst requires a significant amount of voltage continuously sending pulses might not be the best solution.

    I found that using IO_MODE = 1 with a lower amount of pulses and essentially duty cycling the measurements allowed me to have a higher voltage because I allowed the capacitor time to charge appropriately. So in this capture below essentially I send 7 pulses, break for a 1ms then send 7 pulses again. So this is like a pseudo continuous mode.

    Below I tried a burst sending 63 pulses every 8ms, that still seemed to yield ~32Vpp swing compared to ~8Vpp when continuously bursting. If I increased the frequency of the bursts I would still see the 63 pulses but the voltage was just reduced.

    I hope this helps!

    Best,

    Isaac

  • 0 in reply to Isaac Lara
    TI__Genius 9560 points

    Hi Isaac,

    Thank you very much for your help, and about if it could generate continuous pulses with the BURST_PULSE = 0 for IO_MODE 0 and 1, I am waiting for your feedback. Very appreciated.

    Best regards

    kailyn

  • 0 in reply to Kailyn Chen
    TI__Mastermind 23045 points

    Hello Kailyn,

    The designer will not return to office until tomorrow. Hopefully he is able to review and give me a response then if not hopefully by Thursday.

    Best,

    Isaac

  • 0 in reply to Isaac Lara
    TI__Genius 9560 points

    Hi Isaac,

    Any other updates about BURST_PULSE = 0 for IO_MODE 0 and 1?

    Best regard

    Kailyn

  • 0 in reply to Kailyn Chen
    TI__Mastermind 23045 points

    Hello Kailyn,

    I have not heard anything back from the digital design team. I have pinged them again for an update.

    I will  keep you posted when I get a response.

    Best,

    Isaac

  • +1 in reply to Isaac Lara
    TI__Mastermind 23045 points

    Hello Kailyn,

    Thanks for the patience here. I just got a response from the digital design team. The continuous burst option is only available in IO_MODE = 2 for the TUSS4440. This is not an option on IO_MODE = 0 or 1.

    Best,

    Isaac