This is the schema: http://i.imgur.com/dfH33NF.jpg of the project which I've found and want to build. In this project both RTC and LCD uses the same analog pins A4 & A5. As I read this is because both these devices uses I2C bus. I found this information on google however I couldnt find it on the devices, how can I know whether ther is I2C support or not.
The difference from the above project is that I have this LCD: Touch Screen Shield for Arduino UNO – misc.ws
Morover I have RTC, Arduino Uno.
Q1) First thing which I dont understand was when I started sample Adafruit_Gfx paint example with TouchScreen library usage. Code defines the same pins A1 and A2 for the LCD and touch layer - these are two different devices one could say. Does it mean that it uses I2C bus?
Q2) And more important question is will I be able to connect RTC which uses two analog pins RTC DS3231 + 24C32 I2C and to which PINs? If A0-A4 will be taken by LCD and TouchScreen, A5 is free, can I connect RTC to A4 and A5 or A3 and A4 ?
#define YP A1 // must be an analog pin, use "An" notation! #define XM A2 // must be an analog pin, use "An" notation! #define YM 7 // can be a digital pin (9 uno)(pin 23 Mega) #define XP 6 // can be a digital pin (8 uno)(pin 22 Mega) #define TS_MINX 150 #define TS_MINY 120 #define TS_MAXX 920 #define TS_MAXY 940 // For better pressure precision, we need to know the resistance // between X+ and X- Use any multimeter to read it // For the one we're using, its 300 ohms across the X plate TouchScreen ts = TouchScreen(XP, YP, XM, YM, 300); #define LCD_CS A3 #define LCD_CD A2 #define LCD_WR A1 #define LCD_RD A0 // optional #define LCD_RESET A4