Actions
Forum Thread Details
  • Replies 21 replies
  • Subscribers 634 subscribers
  • Views 1292 views
  • Users 0 members are here
Related

Raspberry Pi I/O pins.

DAB

Hi all,

 

I was doing some testing yesterday and discovered that the I/O pins on the RPi come up with interesting voltages on powerup.

 

I had just assumed that they would all come up at ground state, but we measured several pins and found them at 0.7, 1.2, 1.7, and 2.7 volts output.

 

We were trying to debug a driver circuit I designed, but noticed the default was at 1.2 volts and thought we might have a defective board. So we installed a brand new RPi 3 and found the pins at the above stated levels.

 

I am VERY disappointed in the RPi designers for not defaulting the pins to ground state until they are accessed by software.

 

Hopefully, they will correct this oversight in the next version.

 

Having random output levels could really do some damage to external circuits wired into an RPi.

 

DAB

Parents Reply
  • in reply to Jan Cumps

    Hi Jan,

     

    I cannot share details as it is a project under an NDA, but the circuit is just a simple transistor driver to boost the current drive from the RPi to another SBU device.

    As I said, I was just surprised that the outputs from the RPi varied all over the place.

     

    Now that I know what is going on, I can adjust the circuit accordingly.

    I just wanted everyone here on element14 to be aware.

     

    DAB

Children
No Data