56 lines
1.3 KiB
C
56 lines
1.3 KiB
C
#include "serial.h"
|
|
#include "io.h"
|
|
#include "irq.h"
|
|
|
|
#define PORT 0x3f8 /* COM1 */
|
|
#define SERIAL_MAX_SPEED 115200
|
|
|
|
/* The type of parity. */
|
|
#define UART_NO_PARITY 0x00
|
|
#define UART_ODD_PARITY 0x08
|
|
#define UART_EVEN_PARITY 0x18
|
|
|
|
/* The type of word length. */
|
|
#define UART_5BITS_WORD 0x00
|
|
#define UART_6BITS_WORD 0x01
|
|
#define UART_7BITS_WORD 0x02
|
|
#define UART_8BITS_WORD 0x03
|
|
|
|
/* The type of the length of stop bit. */
|
|
#define UART_1_STOP_BIT 0x00
|
|
#define UART_2_STOP_BITS 0x04
|
|
|
|
void initSerial(int speed)
|
|
{
|
|
unsigned short div = SERIAL_MAX_SPEED / speed;
|
|
outb(PORT + 1, 0x00); // Disable all interrupts
|
|
outb(PORT + 3, 0x80); // Enable DLAB (set baud rate divisor)
|
|
outb(PORT + 0, div & 0xFF); // Set divisor lo byte
|
|
outb(PORT + 1, div >> 8); // Set divisor hi byte
|
|
outb(PORT + 3,
|
|
UART_NO_PARITY | UART_8BITS_WORD | UART_1_STOP_BIT); // 8 bits, no parity, one stop bit
|
|
outb(PORT + 2, 0xC7); // Enable FIFO, clear them, with 14-byte threshold
|
|
outb(PORT + 4, 0x0B); // IRQs enabled, RTS/DSR set
|
|
}
|
|
|
|
int isTransmitEmpty()
|
|
{
|
|
return inb(PORT + 5) & 0x20;
|
|
}
|
|
|
|
void writeSerial(char a)
|
|
{
|
|
while (isTransmitEmpty() == 0)
|
|
;
|
|
|
|
outb(PORT, a);
|
|
}
|
|
|
|
void serial_do_irq(int level){
|
|
if(level == IRQ_COM1){
|
|
char c = inb(PORT + 5) & 1;
|
|
writeSerial(c);
|
|
}
|
|
return;
|
|
}
|