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MSP430G2553 Energia - SD card interfacing and DMA

Raghav Thiru
Prodigy 30 points
Other Parts Discussed in Thread: MSP430G2553, ENERGIA, MSP-EXP430FR5994, CCSTUDIO, MSP-FET

Hi!

I saw the data sheet for MSP430G2553 and read that it has a DMA. This means that I can send ADC values from my MSP directly to the SD card right?

  • How can I do this?
  • Also, how do I use the DMA in Energia? 
  • Data sheet says the sampling frequency is 200kHz, but I'm able to get only 9.6kHz because of the hardcoded FTDI built in the MSP launchpad. How do I bypass this?

Thanks in advance! :)

  • 0
    TI__Guru**** 202256 points

    Hi Raghav,

    The MSP430G2553 does not have a true-form, dedicated general-purpose DMA so you are most likely referring to the ADC10DTC. There are some similar requests with valuable responses already provided on the E2E forum:

    e2e.ti.com/.../668839
    e2e.ti.com/.../228265

    Furthermore, TI provides several ADC10 DTC examples in the MSP430G2xx3_Code_Examples software package: www.ti.com/.../slac485

    Look for msp430g2x33_adc10_[08 through 16]. There are no API calls for DMA/DTC functionality in Energia so you will have to use basic C code to accomplish this task. The 9600 baud rate limitation only pertains to the eZ430 backchannel UART to a host computer and should not affect the SD card interface, which is most likely using SPI.

    BTW: The new MSP-EXP430FR5994 has an on-board SD card and interface code demos, definitely worth looking into!

    Regards,
    Ryan

  • 0 in reply to Ryan Brown1
    Prodigy 30 points

    Thanks for the reply Ryan.

    1) I use a Mac. What do you suggest I use besides Energia? Must I switch to Windows in order to use the MSP without the Energia IDE?

    2) I understand that the 9600 limitation pertains only the UART. But when my code simply makes an integer increment each time in the loop after analog reading a value, and then prints the count every second, I get only 9600 values. Why does this happen?

  • 0 in reply to Raghav Thiru
    TI__Guru**** 202256 points
    Raghav,

    CCSTUDIO can be downloaded to Mac OS devices or is available through CCS Cloud. The number of conversions each second depends on the ADC settings, which have not been provided on this post.

    Regards,
    Ryan
  • 0 in reply to Ryan Brown1
    Prodigy 30 points

    The CCS version for macOS does not support MSP430G2 boards. Are there any other viable options? I've tried searching, but still haven't found a way to program the board in C/C++.

    When you say ADC settings, d'you mean I can tinker around with them? I have not done anything with the settings as far as I can tell, and yet I am stuck with the 9600 problem. It just will not increase. :(

  • 0 in reply to Raghav Thiru
    TI__Guru**** 202256 points
    MSP430G2 devices are supported, but not by the eZ430 FET tool that comes on the MSP-EXP430G2 LaunchPad. If you were to use a MSP-FET tool then it would be able to successfully program/debug a MSP430G2 device.

    ADC sampling frequency is most likely determined by the Energia API, which is why you either need to manually change the ADC registers inside the Energia interface or switch to a C code format with CCS.

    Regards,
    Ryan

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