linderman wrote:Hello all,
when it is safe to connect GPIOs?
Only when RPi is totally disconnected from power source?
RPi can show only red indicator?
Or the ambitious one - GPIOs can be connected when RPi is fully running?
I want to connect some LEDS and play, but i think it will be too show if after every change in the LEDS, connectors and so on i have to turn off Pi and unplug it from power source , then connect it again and start it...
It depends upon your interpretation of "safe" ie. there is greater risk to the Pi than you. It also depends upon how you are (physically) making/breaking the connections. Generally speaking the GPIO's are not "plug'n'play" ie. it's better to plug/unplug (multiple) connections with the Pi powered down - that way you can "double-check" your "new" wiring to make sure that, for example, you haven't connected something providing more than 3.3V to a GPIO pin (which will fry the Pi).
Still running Raspbian Jessie or Stretch on some older Pi's (an A, B1, 2xB2, B+, P2B, 3xP0, P0W, 2xP3A+, P3B+, P3B, B+, and a A+) but Buster on the P4B's. See: https://www.cpmspectrepi.uk/raspberry_pi/raspiidx.htm