I destroyed two I/O pins doing so...

Geert Vancompernolle a écrit :

>Hi,
>
>I read in the documentation that all pins on the two 40 pin connectors
>are 5V tolerant.
>
>I'm currently using the I2C pins of the connector and they're
>connected to two series resistors of 100 Ohm (one for clock, one for
>data), which are connected to a PCF8574 device.
>
>The PCF8574 device is powered with +5V (also coming from the 40 pin
>connector).  The signal levels of the I2C bus are 3.3V at the I2C
>inputs of the PCF8574.  I know this is sufficient, but I would like to
>use a pull-up resistor of 5k6 to +5V for both SDA and SCL to increase
>the level to +5V.  Like this:
>
>          +5V 
>           |
>           _ 
>          | |
>          |_|
>           |   ___
>SDA-FOX ------|___|----> SDA-PCF8574
>
>Same for SCL.
>
>Is this allowed?  Will I not harm the I/O ports of the FoxBoard?
>
>Best rgds,
>
>--Geert
>
>
>  
>

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