Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
14 years ago

banks and gpio and ports

I noticed that the Cyclone III has banks and the pins are labeled IO and list other functions.....

Are the gpio pins assignable or assigned to a port like a 8 bit or 16 bit port ? I am used to programming pic microchip where each GPIO pin is assigned to a port (ex LATA, PORTD, PORTA)

Are all the gpio pins independently assignable to my own specified port or are they split into 8+ bit ports on each bank ?

Thanks

4 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    14 years ago

    Sure. Any pio pin is freely assignable to any general purpose I/O pin.

    You are neither required to route all N signals of a N-bit pio port to the same i/o bank
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    14 years ago

    the I/Os are essentially independent. there are exceptions when doing wide, high speed buses like RAM interfaces and LVDS buses

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    14 years ago

    what is the top speed attainable by an assigned pin if the code was strobing it?

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    14 years ago

    You find such information in the device datasheet, although this will be an upper limit.

    The maximum switching frequency is actually limited by some design specific aspects; for example the selected i/o standard and slew rate strength, external capacitive loading.