IORD 11.0 vs IORD 9.1

[Altera_Forum]

Hello, 

  Code:     --- Quote Start ---  int main() {  int i;    while(1)  {  i = IORD_ALTERA_AVALON_PIO_EDGE_CAP(BUTTON_BASE);  printf("PIO EDGE CAP: %d\n", i);  IOWR_ALTERA_AVALON_PIO_EDGE_CAP(BUTTON_BASE, 0x0);  usleep(1000000);  } }  --- Quote End ---     BUTTON is a 4-bit PIO in my SOPC.   If I run this code with Nios II 9.1 I read: PIO EDGE CAP: 0 If I press BUTTON[0] I read: PIO EDGE CAP: 1 .. If I press BUTTON[3] I read: PIO EDGE CAP: 8   Now: If I run the same code with Nios II 11.0 I read: PIO EDGE CAP: 512 If I press BUTTON[0] I read: PIO EDGE CAP: 513 .. If I press BUTTON[3] I read: PIO EDGE CAP: 520   What does it means? http://bestringtones.mobi/zedge-ringtones/

[Altera_Forum]

Decimal 513 = Hex 201 

Decimal 520 = Hex 208 Then the changing bits are the same in both versions Since it's a 4-bit PIO you must consider the bits above 4 as "don't care". Their status is not deterministic.