I looked into the arduino mega 2560 refernce design
and on some port there's bits that ait connected to anything.
like PD4-6,PE2,PE6-7,PG3-4,PG6-7,PH2,PH7,PJ2-7.
Will those bits always stay 0 (in DDR,PORT,PIN) ?
I don't know, but it would be easy to mask them out just to be safe.
...R
manmaor:
I looked into the arduino mega 2560 refernce design
and on some port there's bits that ait connected to anything.
like PD4-6,PE2,PE6-7,PG3-4,PG6-7,PH2,PH7,PJ2-7.Will those bits always stay 0 (in DDR,PORT,PIN) ?
Those bits will function internally in the chip, just not wired to any circuit traces & connectors. This applies to the original mega1280 board as well. There are some vendors that add extra traces and connectors to allow access to all the I/O pins (Seeeduino is one brand).
manmaor:
I looked into the arduino mega 2560 refernce design
and on some port there's bits that ait connected to anything.
like PD4-6,PE2,PE6-7,PG3-4,PG6-7,PH2,PH7,PJ2-7.Will those bits always stay 0 (in DDR,PORT,PIN) ?
No, they exist. They aren't connected to anything, so will be floating (thus PINx will
not always be zero). DDR and PORT will probably be at zero after reset, but the
currect thing to do is assume nothing and mask out all irrelevant bits when doing
direct port manipulation.