I am working on a Arduino Mega Variant and I did a pin map for the TQFP Pinout.
First I would like a second set of eyes and please let me know If I am missing anything or if there is something incorrect.
Second, I would like to know why only 70 GPI/Os are used and not all 86?
As you can see, Other than the obvious GND or VCC there are 16 pins not connected to anything and if you add up the GPI/Os used, 54 Digital + 16 Analog = 70. The Datasheet states there are 86 GPI/Os, 86 - 70 = 16 pins not used.
Are these pins available in the software, but just didn't fit the design on the Arduino MEGA baord?
Third, I think the RX0/0 and TX0/1 is incorrect. The data sheet does not state that Pins 2 and 3 are pwm pin outs and all other pwms are listed as a clock, i.e OC1A or OC2A. so which pins are actually pwm 0 and 1? NOTE: this has been correct, see post below. Image also is corrected.
Also, Pins 38, 39, 40 should be PWM 16 bit pins, but they are not shown as such. instead the mega uses 3 of the 8 bit PWMs, pins 1, 18, and 23. The 16 bit PWMs have 3 channels (i.e. OC1A, OC1B, OC1C) and the 8 bits only have 2 channels.
Any further info would be great. Thanks