“The input current however is something nobody usually cares about as in digital circuits we usually assume low impedance outputs and high impedance inputs.”
What is the minimum current value into the Pi’s GPIO input?
Push buttons – should I be using a resistor or not? (yes)
Bread Board Setup for Input Buttons
GPIO Electrical Specifications
GPIO pin pull state on powerup
New
dt-blob.bin not working for RaspberryPi 3+ ?
New “gpio” config command
New “gpio” config.txt command announcement
Old
Changing the default pin configuration
Device Trees, overlays, and parameters
github.com/raspberrypi/firmware/blob/master/extra/dt-blob.dts
Enabling Pullup and Pulldown Resistors on The Raspberry Pi
Device Tree Overlay to adjust GPIO Outputs
Raspberry Pi GPIO states at boot time
Raspberry Pi Device Tree and Overlay Configuration
GPIO pin states on powerup [duplicate]
Default pin pull state upon boot
Power on behaviour
Override GPIO state at boot (2016)
GPIO Pin States a Boot time – Change in 3.6.11+ (2013)
5V to 3.3V
- 0.0V – 2.0V = LOW
- 2.1V – 3.3V = HIGH
Books
Exploring Raspberry Pi: Interfacing to the Real World with Embedded Linux
“CMOS gate inputs have extremely large resistance and draw almost no current, allowing large fan-out capability.”