參考：

1）《USER'S MANUAL-S3C6410X》第31章 UART

2）u-boot uart初始化及讀寫：u-boot-x.x.x/board/samsumg/smdk6410/lowlevel_init.S

   　　　　　　　　　　　　 u-boot-x.x.x/cpu/s3c64xx/serial.c

3) 內核串口驅動：linux-x.x.x/driver/tty/serial/s3c6400.c samsung.c serial_core.c

代碼：

uart.c

 1 #include 'uart.h'

 2 

 3 #define GPACON        (*((volatile unsigned long *)0x7f008000))

 4 

 5 #define ULCON0        (*((volatile unsigned long *)0x7f005000))

 6 #define UCON0        (*((volatile unsigned long *)0x7f005004))

 7 #define UFCON0        (*((volatile unsigned long *)0x7f005008))

 8 #define UMCON0        (*((volatile unsigned long *)0x7f00500c))

 9 #define UTRSTAT0    (*((volatile unsigned long *)0x7f005010))

10 #define UERSTAT0    (*((volatile unsigned long *)0x7f005014))

11 #define UFSTAT0        (*((volatile unsigned long *)0x7f005018))

12 #define UMSTAT0        (*((volatile unsigned long *)0x7f00501c))

13 #define UTXH0        (*((volatile unsigned long *)0x7f005020))

14 #define URXH0        (*((volatile unsigned long *)0x7f005024))

15 #define UBRDIV0        (*((volatile unsigned long *)0x7f005028))

16 #define UDIVSLOT0    (*((volatile unsigned long *)0x7f00502c))

17 #define UINTP0        (*((volatile unsigned long *)0x7f005030))

18 #define UINTSP0        (*((volatile unsigned long *)0x7f005034))

19 #define UINTM0        (*((volatile unsigned long *)0x7f005038))

20 

21 void uart0_init(void)

22 {

23     GPACON &= ~0xff;

24     GPACON |= 0X22;

25     

26     ULCON0 = 0x03; //data frame: 8n1

27     /*

28     clk: pclk

29     tx int type: level

30     rx int type: pulse

31     rx err int enable

32     tx/rx mode: interrupt or polling 

33     */

34     UCON0 = 0x245; 

35     UFCON0 = 0x00; //disable fifo;

36     UMCON0 = 0X00; //disable auto flow control(AFC)

37     /*

38     DIV_VAL = UBRDIV + (num of 1's in UDIVSLOT)/16

39     DIV_VAL = (PCLK/(bps*16))-1 = (66000000/115200)-1=34.8

40     UBRDIV = 34;

41     num of 1's in UDIVSLOT = 13; 

42     */

43     UBRDIV0 = 0x22;

44     UDIVSLOT0 = 0x1fff;

45 }

46 

47 int uart0_getc(void)

48 {

49     while (!(UTRSTAT0 & 0x1));

50     return (URXH0 & 0xff); 

51 }

52 

53 void uart0_putc(const char c)

54 {

55     while (!(UTRSTAT0 & 0x2));

56     UTXH0 = c;

57     if (c == 'n')

58     {

59         uart0_putc('r');

60     }

61 }

62 

63 void uart0_puts(const char *s)

64 {

65     while (*s)

66     {

67         uart0_putc(*s++);

68     }

69 }