Signal Voltage Level

05 Jun 2011


I am looking to get my mbed talking to a slave PIC with SPI. I intend to leave the mbed attached to the USB cable and use the 3.3V output to run the PIC. Now my question is what will the output voltage of the SPI lines be from the mbed? Given that the PIC is powered to 3.3V will there be issues if the mbed logic '1' is 5V?

Ideally I would check this myself with a scope but I don't have one at home, yet ...

Any help would be great, even if it is just to point to a document with this in :-)



05 Jun 2011

mbed logic levels are 3.3V. The only exception is the VU pin which outputs 5V from the USB connector and nothing if USB is not connected.

"Digital IO pins are 3.3v, 40mA each, 400mA max total"

06 Jun 2011

Thank you, can't believe I missed that - didn't scroll down the page far enough!


22 May 2014

For the newbies.... That page was moved to platform section. And such piece of info does not longer exists. It would be nice the correction was made along with the pinout definition. Its just too simple and I cant tell wich UART Im using.