I am a relative newbie with tons of electronic experience but not so much programming. So I am working with an Arduino Uno R3 in Win 7 Pro using the Arduino IDE ver 1.6.3.
The idea was to use the PCF8574N to control a 16x2 LCD: (P0 to RS, P1 to RW, P2 to en, P4 to d4, P5 to d5, P6 to d6, P7 to d7.) But I cant even get that far. I was wanting to scan the PCF8574 to verify the address, I THINK it is 0x40 (0100 000), but none of the assorted versions of I2C scanners work. Inserting code to turn the Uno R3 onboard led on just before endTransmission works fine but turning off immediately after never happens. None of the connecting wires are over 7cm long, power and ground are good at 5.0vdc and 4.7k pullups are on the SDA and SCL lines.
I have downloaded Mr. Gammons I2C_Rev5.zip library and am trying to use it in his I2CScanDevices.ino which looked promising but having no luck. My newbie attempts to substitute the I2C_Rev5 functions for the Wire functions is apparently over my head and after 14 hours reading, experimenting, rewiring, replacing parts, etc I am no closer to scanning the I2C address of my PCF8574N set up with all address lines pulled low than when I started. I have even disconnected all lines to the PCF device except for power, ground SDA and SCL but no change, every scan.ino I run hangs at the same place.
Any ideas or perhaps a scanner sketch that has the I2C_Rev5 restart functions in it? Thank you for your time.