Hm, just a small question. As i soldered the missing headers to the Mega i saw that the lines are all, as expected, numbered... but what surprised me is the following:
I2C lines SDA and SCL are 20 and 21, The rx and tx 1 to 3 are numbered 14 to 19. Are those accessible like any others? Also, what i wonder about most is the line of pins saying PE2, PE6, PE7, PG3...., PH7, PH2
What are those?!
I2C lines SDA and SCL are 20 and 21, The rx and tx 1 to 3 are numbered 14 to 19. Are those accessible like any others? Also, what i wonder about most is the line of pins saying PE2, PE6, PE7, PG3...., PH7, PH2
What are those?!
The 20,21 and 14-19 pin numbers are the Arduino software abstraction pin numbers of those I/O pins and can be used as simple digital reads and writes using those Arduino assigned abstraction pin numbers. Just as the sixteen analog pins, A0 to A15 are ALSO avalible as digital I/O pins by referencing them as digital pins 54 to 69.
The 16 pins labled PE2 through PH2 are somthing different all together. The Arduino Mega did not run traces from the processor chip to any connectors for these 16 bits so that they are also not 'mapped' into the Arduino software core libaray at all and can not be referenced with a Arduino abstraction pin number.
The Seeeduino Mega board did run these traces to connector pads, however because the Arduino core software did not map these 'extra' 16 digital pins, they can only be used if you utilize direct port read and write access statements using PORT, DDR and PIN registers using ports E,G,D,J and H and then masking the individual I/O bits.
http://www.arduino.cc/en/Reference/PortManipulation
Lefty
Oh, alright, that was a great explaination :0)
Thanks