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MSPM0L1303: signal delaying

HS FAE Germany
Mastermind 31690 points
Part Number: MSPM0L1303

Tool/software:

Hi,
customer has a 307KHz (50% duty cycle) signal on his PCB and has to delay it for 200ns. My idea is to generate 307KHz PWM signal with the timer which can be syncronized with the customer 307KHz signal through GPIO. A 2nd PWM with 307KHz and phase delay of 200ns (to the 1st PWM) can then be generated and output. Would that work?

Regards, Holger

  • 0
    TI__Guru 68141 points

    Hi Holger,

    I'm not quite sure.  I'll need some more information about the application for the reason for the delay.  What is the delay relative to? A periodic signal, some other timing in the MSP, etc.?

  • 0
    Guru 41995 points

    It is hard to coordinate separate timers like that. I would just trigger an interrupt on the edge, and in the interrupt routine, wait 200 ns before turning on/off the GPIO.

    Or use a monostable multivibrator to trigger a latch.

    www.electronics-tutorials.ws/.../monostable.html

    Or about 300 feet of coax. 8^)

  • 0 in reply to Keith Barkley
    TI__Mastermind 31690 points

    I don't think you you can do it in SW or per interrupt. The sys clock is 24MHz -> 42ns (200ns = 5 clocks). I think when you trigger a GP input interrupt and then set/reset a GP output the internal delay will be longer then 200ns.

  • 0 in reply to HS FAE Germany
    TI__Guru 68141 points

    Hi Holger,

    I'm still thinking what might work as a solution.  Can you describe how the the 200ns delay is used, ie., is there some event in the system that triggers the start of the PWM and from this event there must be a 200 ns delay?

  • 0 in reply to Dennis Lehman
    TI__Mastermind 31690 points

    Hi Dennis,
    there are two 307KHz signals to control 2 power supplies. The one signal is delay today and therefore produce inefficiency. The two PWM signals should be as syncron as possible. The delay should be around 200ns.
    My idea is to use the comparator and output the signal to an GPIO pin. May be the comp filter could be configured to be ~200ns.
    The other idea is to use the phase shift of the timers and syncronize with an input GPIO.

    Regards, Holger