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MSP432P401R: MSP432P401R

cristal garcia
Prodigy 50 points

Part Number: MSP432P401R

hi, im trying to program a dc/dc boost converter using msp432p401r , and m trying to get a PWM with a frequency of 25KHZ and duty cycle of 93%, i already read all manuals and guides but still i dont understand how to set my desired values, does someone can help please!!

thank you

  • 0
    Guru 103225 points

    What do you have so far?

    Example msp432p401x_ta1_16.c demonstrates the mechanics:

    http://dev.ti.com/tirex/explore/node?node=ABQIQVo5QZQgP-pLgBCbbg__z-lQYNj__LATEST

    The only trick is to figure out the constants. That program counts up to 1000 (period) using a 3MHz clock, so the PWM frequency is 3000000/1000 ticks=3000 Hz. Flipping that around, you want a period of 3000000/25000Hz=120 ticks. The on/off compare value would be 93%*120=~112 ticks.

  • 0 in reply to Bruce McKenney
    Prodigy 50 points

    thank so much, but now im confuse with the output pin that will be connected to the breadboard? i see that P.7.7 and P.7.6 are the pins in the chip no connectors?  which one is the output pin in the connectors? is the the P.7.7 and P.7.6, doing reference to J2 but which pin?

  • 0 in reply to cristal garcia
    Guru 103225 points

    What platform are you using? On the Launchpad, P7.6/7 are on J5. Out of the box, there are no header pins installed there.

    -One solution is to solder headers there.

    -If that's infeasible, you can use P2.4/5 (TA0.1/2) which are (installed pins) on J2. To do this, you need to

    1) change the TIMER_A1 references to TIMER_A0

    2) Change the P7 references to P2

    3) Change the BIT6 and BIT7 references to BIT4 and BIT5. The SEL0/1 settings appear to be the same [Ref data sheet (SLAS826G) Table 6-67]

    This example produces two PWM outputs, one at 25% and one at 75%, both at 3kHz. From your description you only need one, so just pick one.

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