BDD: Header2 on an Arduino Mega2560R3


All pins on the 2nd header of the Mega2560 only involve the ATmega2560 mcu chip or the GND and +5V nets:

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Apart from most pins acting as digital I/O pins, the 2nd header also offers access to:
  • 16 pins for the XMEM expansion points to additional external SRAM, split into 8 pins for multiplexed data and low order address, and 8 high order address pins.
  • A T0 timer pin.
  • An XMEM Address Latch Enable (ALE) pin
  • An XMEM inverted read strobe RD pin
  • An XMEM inverted write strobe WD pin
  • 3 additional Pulse Width Modulation (PWM) pins
  • Serial Peripheral Interface (SPI) Pins (MISO, MOSI, SCK, SS)

The pin ports in the header block have corresponding pin shared reference properties split across the 2 row blocks, but we won't be using the row blocks further in this trail.

Separate system-wide instances of type GND and +5V with net values (rather than a mapping to a specific pin), have been assigned as Context-Specific Values for pins of corresponding types.

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