hardware

power delivery

In summary, the Raspberry Pi 3 can deliver a maximum of 50 mA to 150 mA from the 3.3V GPIO pins, but care should be taken not to exceed the individual pin limit of 16 mA for each GPIO pin. Always ensure that the total current drawn does not exceed the recommended limits to avoid damaging the board.

3.3V power delivery

All Raspberry Pi since the Model B+ can provide quite a bit more, up to 500mA to remain on the safe side, thanks to a switching regulator.

  • ref - https://pinout.xyz/pinout/pin1_3v3_power/#:~:text=The%203v3%20supply%20pin%20on,regulator%20for%203.3v%20projects.

Shields

RPI4

  • BCM2711B0: cortex-A72

I2C

chip

demo code

can use commands nohup to run script in background for long term.

repository

  • display https://github.com/Edragon/RPI_Display
  • nas - https://github.com/Edragon/RPI_nas
  • matrix - https://github.com/Edragon/RPI_matrix
  • RPI prog - https://github.com/Edragon/RPI-PROG
  • RPI serial - https://github.com/Edragon/RPI-Serial