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MSP430F6459-HIREL: MSP430F6459TPZR

Srinadh Moka
Prodigy 110 points
Part Number: MSP430F6459-HIREL

Can i generate the DAC output voltage as 0.9V ?

Because, with the REF voltage of the DAC mentioned as 1.5V and AVcc we are getting 0.75V and 1.5V peak to peak.

If I want to get DAC output as 0.9V what are the registers do i need to configure.

  • 0
    TI__Mastermind 18470 points

    Hi Srinadh,

    If your reference value is 1.5V then when the DAC value is 4096 (0xFFF) you will get 1.5V. If you want to limit to 0.9 V then you should use 2457 (0x999).

    To get the DAC value the formula is: DAC Value =  Target Voltage * 4096 / Reference Voltage. You will want to update the DAC12x_DAT register. I recommend looking at the User's Guide and the DAC12 section. DAC Example

    Regards,
    Luke

  • 0 in reply to Luke Ledbetter
    Prodigy 110 points

    Hi,

    For that we need to keep the fixed data value in the DAC, but in my application i need to use as variable data like GPS data.

    Suggest any other way to get the peak as 0.9V peak with respect to internal ref voltages.

  • 0 in reply to Srinadh Moka
    TI__Mastermind 18470 points

    Hi Srinadh,

    You can use variabled data for the DAC12_xDAT register, just do some data checking before assigning the value in the DAC12_xDAT register.

    For example

    uint16_t dacValue;
uint16_t threshhold;
//Vref value changes
threshold = 0.9*4096/Vref;

if(dacValue <= threshold)
    DAC12x_DAT = dacValue;
////////////////
//or if you have static references you can define the VREF and change your conditional
#define VREF_15

#ifdef VREF_15
    if(dacValue <= 2457)
        DAC12_xDAT = dacValue;
#ifdef VREF_25
    if(dacValue <= 1474)
        DAC12_xDAT = dacValue;

    The above is psuedocode but should help give you an idea on how you can make sure the DAC does not exceed 0.9V.

    Regards,
    Luke

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