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DC_CAL pin and DC_CAL register of SPI in DRV8301

Kister Genesis Jimenez
Prodigy 210 points
Other Parts Discussed in Thread: DRV8301

Hi!

In the datasheet of DRV8301, section 7.3.2, paragraph 4, it is stated that:

"To minimize DC offset and drift overtemperature, a calibration method is provided through either the DC_CAL pin

or SPI register."

I am currently layouting my drv8301 PCB and it would help me a lot if I can reduce the number of pins I need to connect to my microcontroller. I am planning to pull high the nFAULT, PWRGD and nOCTW but not connect them to microcontroller. I will read all status from SPI. SO if SPI won't work, I'll just test them manually using a multitester on the pull-up resistors. However, for the DC_CAL, it is not clear to me if it is ok to keep it floating or if needs to be pulled-down for normal running conditions. I want my calibration to be activated through the SPI registers. So here are my questions:

1. Which has higher priority on the DC_CAL? is it the DC_CAL pin or is it the DC_CAL register? So if I set my DC_CAL register to active, will it become active even if the DC_CAL pin is low?

2. Depending on the above, what should be my DC_CAL pin default state so that I can use SPI for DC_CAL activation?

  • 0
    TI__Guru** 114905 points

    Hi Kister,

    Kister Genesis Jimenez said:
    1. Which has higher priority on the DC_CAL? is it the DC_CAL pin or is it the DC_CAL register? So if I set my DC_CAL register to active, will it become active even if the DC_CAL pin is low?

    The external DC_CAL pin and DC_CAL register have equal priority. If either are set, the device will enter DC_CAL. The difference is the DC_CAL pin enables calibration on both amplifiers simultaneously while the register bits allow calibration of the amplifiers separately.

    Kister Genesis Jimenez said:
    2. Depending on the above, what should be my DC_CAL pin default state so that I can use SPI for DC_CAL activation?

    If you intend to calibrate through the SPI, you should set the DC_CAL pin to a logic low. Also note EN_GATE = high is needed to perform the calibration.

  • 0 in reply to Rick Duncan
    Prodigy 210 points

    Hi Rick,

    Thank you for a very quick response. I'm going to do what you suggest.