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MSP430FR4133: Not able to achieve excepted sampling rate and plot waveform.

Part Number: MSP430FR4133
Other Parts Discussed in Thread: MSP-EXP430FR4133, BOOST-ADS7042, , ADS7042

Dear All,

I am using boost-ads7042 with msp430fr4133 dev board and programming using energia in my project "USB OSCILLOSCOPE"

I have used the energia SPI Library to interface with ads7042 and I am able to convert Analog sine wave values from signal generator.

I have set my spi speed to 8 MHz.So as per this setting i need to achieve sampling speed of 500 KSPS.

But  practically i am unable to get that.

I am able to plot  upto 50hz sine wave only.

Does baud rate affect the spi speed? if so what should  i set it to?

If not what should be done to get that sampling speed.

Please help me out.

Regards 

BHARAT

 

  • Hi Bharat,

    Before send the data to USB, maybe you could try to verify the ADC sample rate with oscilloscope.

    And are you using MSP-EXP430FR4133 Lunchpad? There is an eZ-FET on board which support baud rate for UART is from 4800 to 115200 and the baud rate is depend on the target configuration and the debug settings, please refer to MSP debuggers UG Table 9 : www.ti.com/.../slau647h.pdf

    regards
    KC
  • Bharat,

    The BOOST-ADS7042_Firmware is a demonstration of the ADS7042's low-power consumption, not the MSP430FR4133's ability to send data over UART. As it stands the sampled data is only sent to the host PC at a baud rate of 9600 and once every iteration of the while loop, not every time a sample is taken. To alter this you will need to increase the baud rate to 115200 and send the data as soon as it is sampled, and even then you will encounter bottle-necking as the baud rate fails to keep up with the sampling speed. The LaunchPad furthermore is only capable of supporting a maximum 250 ksps, not the desired 500k. You will need to lower your sampling speed if continuing to develop with the MSP-EXP430FR4133.

    Regards,
    Ryan