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MSP430F5510: Input Threshold levels for GPIO at Vcc = 2.5V

Steve Widener
Genius 11010 points

Part Number: MSP430F5510

The data sheet does not have levels for the voltage that we are running the MSP430 at, 2.5V

What is the Vih for VCC = 2.5V?

May we use Figure 5-18 to estimate the Vih, Vil and hysteresis levels?

  • 0
    TI__Mastermind 30545 points

    Hello,

    I don't think I would use Figure 5-18 as it's describing the USB port which is powered by VUSB and not the the MCU's VDD, but you can use a similar process to try and estimate it from the table.  It's going to be be somewhere in between the 1.8V and 3.0V data points, so if you you draw a similar line for them, you can estimate.  

    I will say to also remember that it's a pretty wide range between the min and max, but the most important spec is typically the Max when the voltage is positive-going and the Min when the voltage is negative-going.   Estimate those, and if you can hit those numbers, the GPIO will always read the correct value.  

    Thanks,

    JD

  • 0 in reply to JD Crutchfield
    TI__Genius 11010 points

    JD - the concern is that 1.8V logic is being interfaced to the MSP430 (with Vcc @ 2.5V). 

    Will the 1.8V logic be able to meet Vit+ MAX?

    What would be the Vit+ max level with Vcc = 2.5V?

  • +1 in reply to Steve Widener
    TI__Mastermind 30545 points

    Hey Steve,

    If we assume the Vit+ Max is linear with VDD, then my calculation shows @ 2.5VDD a Vit+ max of 1.81V.   So no, I don't think a 1.8V signal would be guaranteed to meet Vit+ max.

    I don't think 1.8V logic should be interfaced directly to the MSP430F5510.   

    In a pinch for a single signal, the could maybe try and use the integrated COMP_B.   

    Do they need USB?  If not, we do offer a family of MSP430F5xx that support 1.8V GPIO through a Split VCC rail.  See the MSP430F5229.  Maybe something in this family can fit their application.  

    Thanks,

    JD

     

      

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