Re: RN52 spontaneously went into firmware update mode

Posted by Mārcis on Oct 07, 2022; 12:06pm
URL: http://bluesaab-forum.90.s1.nabble.com/RN52-spontaneously-went-into-firmware-update-mode-tp1844p1846.html

Hello. The RN52 needs to have 47k resistor between GPIO3 pin and GND otherwise that pin will be "floating" it can fall into DFU mode. To update firmware the GPIO3 is HIGH at boot time (this is done by getting 5v from usb in BlueSaab board).