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MSP430 DSS / sine generator

HS FAE Germany
Mastermind 32310 points
Other Parts Discussed in Thread: MSP430F5338

Hello,customer ask for a MCU with integrated DDS / sine generator for up to 100KHz. Would this be possilbe on the MSP430F5338 with the implemented 12bit DAC?

Regards, Holger

  • 0
    TI__Guru**** 218567 points

    Hi Holger,

    The answer to this question depends on the desired resolution of your sine wave. You would use Timer_A0/A1/A2/B to trigger a DMA conversion from a defined sine wave lookup table to the DAC output. The maximum Timer clock source frequency is 20 MHz (SMCLK) so it might be possible to get 100 points of resolution per wavelength (with CCR0 alternating set and reset on every timer pulse), but this is the best case assuming that setting the DAC output does not create a DMA bottleneck (which it will given that DMA requires two cycles per transfer). Lower wave resolutions, like 16 steps, would be ideal. Here are some related E2E threads:

    e2e.ti.com/.../118618
    e2e.ti.com/.../923149
    e2e.ti.com/.../222699

    Regards,
    Ryan

  • 0 in reply to Ryan Brown1
    Guru 25210 points
    Any DAC output is going to be piece-wise linear and require analog low-pass filtering on the output anyway. So - you may be able to just use the timer output in set/reset mode and filter the hell out of the resulting square-wave output. If the range of frequencies required is narrow enough, this might be a viable alternative.

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