Confusion on AN5252

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Confusion on AN5252

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smiller2
Contributor III

App note seems to give conflicting recommendations for some pins that I am not using.  I am using neither eSDHC nor SPI.   In Table 15, it says to weakly pull down pin SDHC_CLK_SYNC_IN.    However, in Table 26 is says to pull up pin SPI_SIN.   As far as I can tell, these are actually the same pin of the chip, pin U3.    So, should I pull them HIGH or pull them LOW?     Does the pullup termination have to be then factored into the RCW?   In other words, if I pull them up, do I then need to tell the RCW that they are SPI pins?

 

Thanks.

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r8070z
NXP Employee
NXP Employee

You are right SDHC_CLK_SYNC_IN and SPI_SIN use the same pin. In both configurations you can keep it High or Low. It does not care. In other words, if you pull this pin up, you do not need to tell the RCW that it is SPI_SIN pin.

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smiller2
Contributor III

OK,  I will pull them high with resistors.  Thanks.

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r8070z
NXP Employee
NXP Employee

You are right SDHC_CLK_SYNC_IN and SPI_SIN use the same pin. In both configurations you can keep it High or Low. It does not care. In other words, if you pull this pin up, you do not need to tell the RCW that it is SPI_SIN pin.

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