Sonoff Basic doesn't start when GPIO2 is LOW

[Velthuis]

Hi!

I've a Sonoff Basic with the latest hardware revision (Sonoff RF R2 POWER V1.0).
GPIO14 is no longer available and has been replaced with "IO2" which is connected to GPIO2.

GPIO2 needs to be "HIGH" during boot, otherwise EasyESP won't start. Once EasyESP has started I can use the GPIO to detects triggers, this is working fine and stable.

This behavior makes my application unreliable since the sensor might output "LOW" when the Sonoff unit is booting.

Secondly, there seems to be an internal pullup, can this be disabled? My sensor actively pulls down in a "LOW" situation, this conflicts with the internal pullup of the Sonoff unit resulting in +/- 200mV on the GPIO in a "LOW" condition.

Any ideas?

[Shardan]

The ESP8266 has some "special" GPIOs.
It can be started from a SD-Card for example, or it can be started in Flash mode.
These modes are controlled by these special GPIO's.
GPIO2 is one of these special ones. It must be "high" at boot time.
If it is "low", the ESP boots to wrong mode.

[kimot]

At first I suggest using different GPIOs - I am using RX and TX pins from new Sonoffs connector.

Or you must use some circuit like this:

IMG_20190127_094534.jpg (208.64 KiB) Viewed 4775 times

[Velthuis]

Using the RX pin now instead. TX pin has the same behavior !

Thanks!