실험 6-직렬
23175 단어 직렬 포트
개발판: jz2440
시스템: ubuntu 12.04
컴파일러:arm-linux-gcc
둘.UART
아껴.
셋.직접 부호 붙이기
Makefile
1 objs := head.o init.o serial.o main.o
2
3 uart.bin: $(objs)
4 arm-linux-ld -Ttext 0x00000000 -o uart_elf $^
5 arm-linux-objcopy -O binary -S uart_elf $@
6 arm-linux-objdump -D -m arm uart_elf > uart.dis
7
8 %.o:%.c
9 arm-linux-gcc -Wall -O2 -c -o $@ $<
10
11 %.o:%.S
12 arm-linux-gcc -Wall -O2 -c -o $@ $<
13
14 clean:
15 rm -f uart.bin uart_elf uart.dis *.o
16 head.S:
1 @******************************************************************************
2 @ File：head.S
3 @ ： SDRAM， SDRAM， SDRAM
4 @******************************************************************************
5
6 .extern main
7 .text
8 .global _start
9 _start:
10 Reset:
11 ldr sp, =4096 @ ， C ，
12 bl disable_watch_dog @ WATCHDOG， CPU
13 bl clock_init @ MPLL， FCLK、HCLK、PCLK
14
15 ldr pc, =on_sdram @ SDRAM
16 on_sdram:
17 ldr sp, =0x34000000 @
18 ldr lr, =halt_loop @
19 ldr pc, =main @ main
20 halt_loop:
21 b halt_loopinit.c
1 /*
2 * init.c:
3 */
4
5 #include "s3c24xx.h"
6
7 void disable_watch_dog(void);
8 void clock_init(void);
9
10
11 /*
12 * WATCHDOG， CPU
13 */
14 void disable_watch_dog(void)
15 {
16 WTCON = 0; // WATCHDOG ， 0
17 }
18
19 #define S3C2410_MPLL_200MHZ ((0x5c<<12)|(0x04<<4)|(0x00))
20 #define S3C2440_MPLL_200MHZ ((0x5c<<12)|(0x01<<4)|(0x02))
21 /*
22 * MPLLCON ，[19:12] MDIV，[9:4] PDIV，[1:0] SDIV
23 * ：
24 * S3C2410: MPLL(FCLK) = (m * Fin)/(p * 2^s)
25 * S3C2410: MPLL(FCLK) = (2 * m * Fin)/(p * 2^s)
26 * : m = MDIV + 8, p = PDIV + 2, s = SDIV
27 * ，Fin = 12MHz
28 * CLKDIVN， ：FCLK:HCLK:PCLK=1:2:4，
29 * FCLK=200MHz,HCLK=100MHz,PCLK=50MHz
30 */
31 void clock_init(void)
32 {
33 // LOCKTIME = 0x00ffffff; //
34 CLKDIVN = 0x03; // FCLK:HCLK:PCLK=1:2:4, HDIVN=1,PDIVN=1
35
36 /* HDIVN 0，CPU “fast bus mode” “asynchronous bus mode” */
37 __asm__(
38 "mrc p15, 0, r1, c1, c0, 0
" /* */
39 "orr r1, r1, #0xc0000000
" /* “asynchronous bus mode” */
40 "mcr p15, 0, r1, c1, c0, 0
" /* */
41 );
42
43 /* S3C2410 S3C2440 */
44 if ((GSTATUS1 == 0x32410000) || (GSTATUS1 == 0x32410002))
45 {
46 MPLLCON = S3C2410_MPLL_200MHZ; /* ，FCLK=200MHz,HCLK=100MHz,PCLK=50MHz */
47 }
48 else
49 {
50 MPLLCON = S3C2440_MPLL_200MHZ; /* ，FCLK=200MHz,HCLK=100MHz,PCLK=50MHz */
51 }
52 }main.c
1 #include "serial.h"
2
3 int main()
4 {
5 unsigned char c;
6 uart0_init(); // 115200，8N1(8 ， ，1 )
7
8 while(1)
9 {
10 // ， ， 1
11 c = getc();
12 if (isDigit(c) || isLetter(c))
13 putc(c+1);
14 }
15
16 return 0;
17 }serial.h:
1 void uart0_init(void);
2 void putc(unsigned char c);
3 unsigned char getc(void);
4 int isDigit(unsigned char c);
5 int isLetter(unsigned char c);serial.c
1 #include "s3c24xx.h"
2 #include "serial.h"
3
4 #define TXD0READY (1<<2)
5 #define RXD0READY (1)
6
7 #define PCLK 50000000 // init.c clock_init PCLK 50MHz
8 #define UART_CLK PCLK // UART0 PCLK
9 #define UART_BAUD_RATE 115200 //
10 #define UART_BRD ((UART_CLK / (UART_BAUD_RATE * 16)) - 1)
11
12 /*
13 * UART0
14 * 115200,8N1,
15 */
16 void uart0_init(void)
17 {
18 GPHCON |= 0xa0; // GPH2,GPH3 TXD0,RXD0
19 GPHUP = 0x0c; // GPH2,GPH3
20
21 ULCON0 = 0x03; // 8N1(8 ， ，1 )
22 UCON0 = 0x05; // ，UART PCLK
23 UFCON0 = 0x00; // FIFO
24 UMCON0 = 0x00; //
25 UBRDIV0 = UART_BRD; // 115200
26 }
27
28 /*
29 *
30 */
31 void putc(unsigned char c)
32 {
33 /* ， */
34 while (!(UTRSTAT0 & TXD0READY));
35
36 /* UTXH0 ，UART */
37 UTXH0 = c;
38 }
39
40 /*
41 *
42 */
43 unsigned char getc(void)
44 {
45 /* ， */
46 while (!(UTRSTAT0 & RXD0READY));
47
48 /* URXH0 ， */
49 return URXH0;
50 }
51
52 /*
53 *
54 */
55 int isDigit(unsigned char c)
56 {
57 if (c >= '0' && c <= '9')
58 return 1;
59 else
60 return 0;
61 }
62
63 /*
64 *
65 */
66 int isLetter(unsigned char c)
67 {
68 if (c >= 'a' && c <= 'z')
69 return 1;
70 else if (c >= 'A' && c <= 'Z')
71 return 1;
72 else
73 return 0;
74 }좋은 웹페이지 즐겨찾기
