[avr-chat] Array access to ports

[Ron Kreymborg]

I am addressing a dozen or so LEDs on a number of different ports, turning
them on and off. I would like to address them through an array structure
that stores the relevant port and mask. For example:

typedef enum
{
    T_LED_OFF,
    T_LED_ON
} LED_STATE_TYPE;

typedef struct
{
    MYPORT    port;
    uint8     mask;
} LED_TYPE;

I could designate the respective LEDs with names. For example:

typedef enum
{
   LEDOUT,
   etc
} LED;

I had hoped to be able to preload the array something like:

static LED_TYPE LedList[] = {
    {PORTB, 0x20},                // LEDOUT
    {etc}
};

Where the 0x20 is the mask for pin5 of PORTB for the LEDOUT led. I could
then use a simple function to address all leds. For example, turning the
LEDOUT led on (high) would look like:

   ChangeLedState(LEDOUT, T_LED_ON);

And the partial function:

void ChangeLedState(LED index, LED_STATE_TYPE state)
{
   if (state == T_LED_ON)
      LedList[index].port |= LedList[index].mask;
   .
   .

The snag of course is that PORTB is not a constant but an SFR. Can anyone
suggest whether assigning a port like this is possible, and what would be
the definition of MYPORT?

Cheers
Ron