/* keybrd_MCP23017.ino

MCP23017 pin assignments
DESTINATION  PIN PIN_NUMBER  PIN   DESTINATION
     row0    GPB0  1     28 GPA7
     row1    GPB1  2     27 GPA6
             GPB2  3     26 GPA5
             GPB3  4     25 GPA4
             GPB4  5     24 GPA3
             GPB5  6     23 GPA2
             GPB6  7     22 GPA1    col1
             GPB7  8     21 GPA0    col0
     LC 3.3V VDD   9     20 INTA
     GND     VSS  10     19 INTB
              NC  11     18 /RESET   VDD
     LC 19   SCL  12     17 A2       GND
     LC 18   SDA  13     16 A1       GND
              NC  14     15 A0       GND

*/