A common reason for blowing up I/Os like this is different ground potentials between the different bits of equipment you are plugging together.
For example, typical laptops or USB plugtop supplies will, when not connected to anything else, have the 0V on their USB connectors at about 120V AC relative to the ground on any metal-cased equipment that is connected to mains earth. Discharging this voltage difference through an RP2040 I/O pin is likely to damage it.
We get away with this in casual connection of Picos to USB cables because the USB connectors are designed to connect the ground before the data pins. That doesn't necessarily apply when using debug probes, especially if you ever connect up the debug probe while the equipment is powered on.
For example, typical laptops or USB plugtop supplies will, when not connected to anything else, have the 0V on their USB connectors at about 120V AC relative to the ground on any metal-cased equipment that is connected to mains earth. Discharging this voltage difference through an RP2040 I/O pin is likely to damage it.
We get away with this in casual connection of Picos to USB cables because the USB connectors are designed to connect the ground before the data pins. That doesn't necessarily apply when using debug probes, especially if you ever connect up the debug probe while the equipment is powered on.
Statistics: Posted by arg001 — Thu Jul 11, 2024 4:49 pm