PI400 GPIO PROTECTOR

The 40-pin GPIO Protector is made of a 40-pin ribbon cable & a circuit board, the 40-pin ribbon cable is to lead 40-pin GPIO signals from Pi 400 to the circuit board, and the circuit board provides a series of functions to protect the Pi 400 computer.
A tiny switch at the left board edge is to control +5V & +3.3V power supply for the daughter board, the user can switch off the daughter board by switching the tiny switch to the “OFF” position when the user wants to install the daughter board on the 40pin connector, he/she doesn’t have to shut down Pi 400, just need to switch off the power of 40pin GPIO Protector, it protects Pi400 from damage due to hot plug.
All 40 signals from Pi400 are protected by ESD immunity IC including the power signal, ESD immunity IC will absorb the energy of ESD which may come from the daughter boards.
All GPIO signals are protected by current limit resistors-33ohm, and short circuits between GPIOs and GPIO to GND, 5V or 3.3V won’t damage the IO of Pi400.
Although the PMU of Pi400 provides over-current protection, Pi400 won’t properly work when PMU is in protection mode. The over-current limit circuit on the GPIO protector limits 2A@5V and 1.5A@3.3V maximal current draw from Pi400, it voids Pi400’s PMU to shut down the system due to a short circuit or over current of the daughter board, a green LED indicates the status of 3.3V power supply for daughter board, a red LED indicates the status of 5V power. When the daughter board draw too much power from Pi400, LED will blink.
2pcs 220uF capacitors stabilize the power supply of 5V and 3.3V respectively,5*40pin breadboard allows the user to do some experiments without additional cost.