Re: On powerup, GPIO state, relay drive problem
Posted: Thu Sep 21, 2017 1:33 pmFor a regular boot, GPIO 0,1,2 must be HIGH during startup, 15 must be LOW.
During boot and with RST LOW & EN HIGH, GPIO 0,1,2,3,12,13,14 are pulled HIGH, 16 is driven HIGH.
GPIO 15 is pulled HIGH during boot but also driven LOW shortly. It must be held LOW for regular boot.
As said, GPIOs 4,5 are floating during reset and boot and thus safe to use.
GPIOs 3,12,13,14 are pulled HIGH during reset and boot and thus should also be okay, as long as you enable the relays with active low signal.
During boot and with RST LOW & EN HIGH, GPIO 0,1,2,3,12,13,14 are pulled HIGH, 16 is driven HIGH.
GPIO 15 is pulled HIGH during boot but also driven LOW shortly. It must be held LOW for regular boot.
As said, GPIOs 4,5 are floating during reset and boot and thus safe to use.
GPIOs 3,12,13,14 are pulled HIGH during reset and boot and thus should also be okay, as long as you enable the relays with active low signal.