how to use 8 ping as full 8 bit ports in arduino mega?
8 ping
Assuming you meant "8 pins" look for examples of direct port manipulation. For example
DDRD = 0xFF; // set all PORTD pins to outputs
PORTD = B10101010; // set alternate bits on PORTD
Rob
And this chart may come in useful to show what arduino pin numbers coorespond to what port/bit number for either a 328p chip or a mega1280/2560 chip.
https://spreadsheets.google.com/pub?key=rtHw_R6eVL140KS9_G8GPkA&gid=0