Keil Compiler and Unions

[nrmlguru]

Hello,

I have the following code.
I want to define a PORTA at address 0x80;
and then write an 8 bit data to PORTA.
I am not getting the expected result.

typedef union {
byte Byte;
struct {
byte BIT0 :1;
byte BIT1 :1;
byte BIT2 :1;
byte BIT3 :1;
byte BIT4 :1;
byte BIT5 :1;
byte BIT6 :1;
byte BIT7 :1;
} Bits;
} PORTASTR;
PORTASTR *_PORTA=(PORTASTR *)0x80;

#define PORTA _PORTA->Byte


void main()
{
unsigned int i;

while(1)
{
for(i=1000; i>0; i--);
PORTA = 0xFF;
for(i=1000; i>0; i--);
PORTA = 0x00;

}
}

 

[ckshivaram]

its already defined by the manufacturer in the startup code.. it will not allow you to redifne.. you may get error that you are re-defining.................

 

[nrmlguru]

Hello Shivaram,

No it doesn't through an error. But am not seeing address location 0x80 changing.
I want to create my own library for all the hardware registers.