More than one year after I shared my I²C logic level converter for the Robotics TXT, the lastest issue 2016-4 of ft-pedia presents on page 73 a similar circuit.
Unfortunately, it doesn't match with the Level shifting techniques in I2C-bus design application note from NXP.
This is not the first time ft-pedia introduces dangerous circuits.
Issue 2015-4 of ft-pedia suggested on page 44 that pin 9 of the Robotics TXT extension port provided +3.3V power supply. Pin 9 actually corresponds to RX and is used for debugging.
Let's hope no Robotics TXT has been damaged.
The official circuit from NXP