LPSPI using 1.8V instead of 3.3V

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LPSPI using 1.8V instead of 3.3V

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jh1
Contributor III

Hi,

i have a curious problem with i.MXRT1052 using the LPSPI0 interface.

The following pins are used for SPI communication:

jh1_1-1606235320100.png

I noticed that when using SPI in master mode the signals have only 1.8V.

The same pins can also be used for USDHC1 so i thought it must have something to do with 
the USDHC1 voltage selection as mentioned in the reference manual

jh1_2-1606235844684.png

The pin that seems to override the setting is GPIO_B1_14 which can be muxed to  USDHC1_VSELECT. But i use this pin as  GPIO2_IO30 as output pin NOT as USDHC1_VSELECT.
When i set the GPIO_B1_14 to low i do indeed get the desired 3.3V but when i set it to high i only get
1.8V.

Is it indeed the eFUSE override by the gpio pin that causes the problem?
(I don't boot from SD-Card but from NOR-Flash). 

How do i get rid of this behavior?
I want the SPI pins to run with 3.3V. 

Thank you,
Johann

 

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victorjimenez
NXP TechSupport
NXP TechSupport

Hello Johann, 

Are you reproducing this behavior with a custom board or with the RT1050-EVK? If you are using a custom board, are you booting from the fuses or from the GPIOs? Could you please share how you are configuring GPIO_B1_14 as an output GPIO? 

Regards,
Victor 

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