Arduino DUE Un-explained Connections D4, D10

Development Tools IDE 1.x
1

Can someone suggest why in Arduino Due following IO pins are connected together in the Schematic?

  1. Physical Pin-102/Digital Pin D10/SPI_CS0 is also connected with Physical Pin-111/Digital Pin D77

  2. Physical Pin-137/Digital Pin D4/SPI_CS1 is also connected with Physical Pin-112/Digital Pin D87

2

I don't know why , but you can decide whether you set the pin to TIOB7 ---> PC29(Timer Counter 2 channel 0) or SPI0_NPCS0 --->PA28:

 // To select the pin for TIOB7
  PIOC->PIO_PDR |= PIO_PDR_P29;       // The pin is no more driven by the GPIO
  PIOC->PIO_ABSR |= PIO_PC29B_TIOB7;    // Peripheral type B

  // To select the pin for SPI0_NPCS0
  PIOA->PIO_PDR |= PIO_PDR_P28;         // The pin is no more driven by the GPIO
  PIOA->PIO_ABSR &= ~PIO_PA28A_SPI0_NPCS0; // Peripheral type A
3

thanks ard_newbie for your reply but i really wanted to know why D4 is connected with D87 and D10 with D77.