Hello. At first, please sorry for a such lame question but I'm really newbie in this subject. My question is also discussed a little on Arduino forum: http://forum.arduino.cc/index.php?topic=196100.0. I operate with the sensors MAX44008 (datasheet here) and connected SDA pin of the sensor to P6 pin of expander, next passing 01000000 to PCF8574 I’m trying to get the data generated by sensor, from SDA of expander with Arduino board. It doesn’t work. Actually I asked MAX support and they say that this connection is wrong and SDA should be connected to SDA of Arduino only. Is it true? But if it is true, how should I commutate between 4 MAX sensors. It seems that passing 01000000 value to chip only opens P6, i.e. makes voltage +5 at, but reading from expander only show which pins are alive and which aren’t. Am I right? How the signal from sensors should be commutated in this case?3201.MyBoard.zip
A bit information (schematic, photos, Arduino sketch) in the attachment.