Serial Ports: Difference between revisions

==Example Code==

===Initialization===

#define PORT 0x3f8 /* COM1 */

 

outb(PORT + 4, 0x0B); // IRQs enabled, RTS/DSR set

}

 

Notice that the initialization code above writes to [PORT + 1] twice with different values. This is once to write to the Divisor register along with [PORT + 0] and once to write to the Interrupt register as detailed in the previous section. The second write to the Line Control register [PORT + 3] clears the DLAB again as well as setting various other bits.

 

===Receiving data===

int serial_received() {

return inb(PORT + 5) & 1;

return inb(PORT);

}

 

===Sending data===

 

int is_transmit_empty() {

return inb(PORT + 5) & 0x20;

outb(PORT,a);

}

 

==Glossary==