Re: [avr-gcc-list] PORT access

[Àíäðåé]

Hi.

It should work.

void modify_port(u08 adr, u08 mask, u08 data)
{
   u08* pp;
   u08 tmp;
   pp = (u08*)adr;
   pp += 0x20;
   tmp = *pp;
   tmp  &= ~mask;
   *pp |= (data & tmp);
}

Thursday, April 26, 2001, 7:19:25 PM, you wrote:

> I am using CAN-bus with two MCUs, one is an 8515 and the other is an 8535. I
> would like be able to modify a port using the following example;


> 1: void Modify_Port(u08 address, u08 mask, u08 data)
> 2: {
> 3:      u08 tmp;
> 4:      tmp = inp(address); // place port reading in tmp
> 5:      tmp &= ~mask;
> 6:      tmp |= (data & mask);
> 7:      outb(tmp, address);
> 8: }

> I made up this example to demonstrate what I am wanting to do. Is there a
> way? This does not work because the value of address is non-constant. I am
> wanting to be able to modify a port in the other MCU via the CAN-bus. Thus,
> controller 'B' could directly set a bit on a port in controller 'A' to sound
> a buzzer. The 'address', 'mask', 'data' is transferred over the CAN-bus.

> Any help would be much appreciated.

> Marlin


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