The OpenLCD firmware has a built-in “emergency reset” feature. When the screen first boots up, the AVR on the back will watch its RX pin. If that pin is held LOW (aka tied to ground), for 2 seconds, then it will reset all settings to default
However, since the AVR is integrated into the display (I think?) it is unclear which RX pin is being referred to - as there are THREE marked RX, and one labelled RST (reset?). In the above statement about grounding the RX pin, it would be helpful to know which one. None of these are marked as AVR/RX.
At this point I have tried all of them and do not get the indicated message on the display. Suspect the firmware needs to be reloaded and have ordered a ftdi adapter to do so. Would appreciate a reply however, as it may help others.
Hello, did you ever get a response about this? I am having the same problem. I need to issue an emergency reset. I have tried each individual RX’s to ground, and none of them cause the emergency reset.
I had a spare brand new screen. That one is working normally out of the box. However, I still am unable to issue the reset on the working one.
All 3 RX pins are connected so any will work. To do the reset, connect RX and GND ×then× apply power and wait 3 to 4 seconds. Then disconnect RX and GND.
I think I’m doing it correctly. Do you know if the baud rate message still displays on the screen when you try the emergency reset? It just shows the baud rate message as usual when I try the emergency reset.
I don’t recall what message pops up but I believe the baud rate should change to 9600 after the reset and the I2C address will change to the default value. (Whatever the docs say it is)
