How to use boost mode and GPIO characteristics at 3 Volts

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Jay Hamlin
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How to use boost mode and GPIO characteristics at 3 Volts

I am interested in using the DA14586 with a SPI peripheral at 3 Volts. The datasheet only barely mentions that you need to use boost mode to pull the GPIOs to the 3V rail - but it sounds like only a pullup resistor. There are no operating parameters shown for 3V operation and no examples of boost mode I can find on the reference designs. I found the definitions of GPIO_ConfigurePinPower() and GPIO_POWER_RAIL_3V in the SDK but, again, its not clear that the GPIOs can operate at 3 Volts. I need 3V push-pull for SPI.

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PM_Dialog
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Hi Jay Hamlin,

Hi Jay Hamlin,

In boost mode configuration, the maximum output that can be achieved in general is 2.4 V. What you are trying to accomplish it is highly not recommended.  We could do some tweak to increase the voltage but that will create an unstable system behavior. In buck mode configuration it is always possible.

Thanks, PM_Dialog

Jay Hamlin
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Ok, but just to clarify: I

Ok, but just to clarify: I will provide whatever voltage is required. Buck or boost I don't care except the datasheet says I can only select the 3V gpio in boost mode. you said "in buck configuration it is always possible" - please clarify, what is "it"? I can use 3 Volts? Can I remove the buck inductor and just supply the voltage myself? Thank you.

PM_Dialog
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Hi Jay Hamlin,

Hi Jay Hamlin,

Regarding the datasheets, the DA14585 supports both buck and boost mode, but the DA14586 supports only buck mode. In the DA14586 you can use 3V GPIO output and you can remove the buck inductor and just supply the voltage yourself. The supply voltage is usually at 3V.

Thanks, PM_Dialog