Reading and writing individual port pins.

/*-------------------------------------------------------------*-
Reading and writing individual port pins.
NOTE: Both pins on the same port
-*-------------------------------------------------------------*/
#include <reg52.H>
void Write_Bit_P1(const unsigned char, const bit);

bit Read_Bit_P1(const unsigned char);
/* ............................................................... */
void main (void)
{
bit x;
while(1)
{
x = Read_Bit_P1(0); /* Read Port 1, Pin 0 */
Write_Bit_P1(1,x); /* Write to Port 1, Pin 1 */
}
}
/* --------------------------------------------------------------- */
void Write_Bit_P1(const unsigned char PIN, const bit VALUE)
{
unsigned char p = 0x01; /* 00000001 */
/* Left shift appropriate number of places */
p <<= PIN;
/* If we want 1 output at this pin */
if (VALUE == 1)
{
P1 |= p; /* Bitwise OR */
return;
}
/* If we want 0 output at this pin */
p = ~p; /* Complement */
P1 &= p; /* Bitwise AND */
}