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DRV8825 and CPG004 EVM

Other Parts Discussed in Thread: MSP430F1612, MSP430G2553, DRV8825, MSP430F5340

I'm looking at this design which uses a MSP430F1612. I was wondering if a lower cost MSP430 could be recommended as a potential replacement.

  • Hi George,

    The value line series of the MSP430 can be used. The MSP430 required really depends on your application. If you plan to set VREF to a fixed value, you don't need a DAC. If you plan to set the DECAY and MODE inputs to fixed states, the number of GPIOs are reduced. For a base application, you can get by with 6 GPIOs; nFAULT as an input and nENBL, STEP, DIR, nRESET, and nSLEEP as outputs.

    Look at the MSP430G2xxx series. Since we don't know the rest of your system, you will have to determine which one matches your needs. For reference, we have used the MSP430G2553 in several similar applications.

  • At this point I'm researching options. I'm thinking of designing a "general" board with the main focus to handling the DRV8825 but having some flexibility to allow the use to use the MSP430 for other tasks.

    I looked at the firmware and it seemed rather large but I wasn't sure when it was compiled how much flash was needed.

  • Hi George,

    The DRV8825 code has several additional features that may not be required. There is code to communicate with the GUI through a UART, and code to handle multiple devices. Once compiled, the .map file can be examined to determine the size of the code. For the DRV8825 EVM code provided, the size is just  4276 bytes FLASH and 162 bytes RAM. I suggest that you write the code using the MSP430F1612 to determine the code size required. Then you can determine which MSP430 variant will meet your needs. If there is little extra space available, please consider using the next largest in case the code must grow.

  • Hi Rick:

    Thanks for the feedback. Knowing that the code compiles down to ~4k really helps. My goal is for this board to work with your GUI just so the user can immediately start with something. Since the GUI communicates over UART I assume that any MSP with a UART will still work with the GUI? I like the price point of the MSP430G2553 and I see it adds Cap touch which is a nice feature to offer. I might have budget for a 5 series part which would allow me to offer a 12-bit SAR. As an example I was looking at the MSP430F5340 which might be a bit overkill but it does seem to offer a bigger bang for buck if I can squeeze in the extra $1 of cost into this product.

    Your thoughts are appreciated.

    Thanks,

    George

  • Hi George,

    This is probably a good time to ask the folks at the MSP430 Microcontrollers Forum. They are much more knowledgeable regarding the variety of devices available. I will be glad to assist if you need additional information regarding the DRV8825 or any other DRV8xxx devices.

  • Thanks Rick, yes, I think you've answered what I needed to know about the DRV8825, now I'm off to the MSP430 group to see what input they have.