TQ6410串口不能输入和输出的问题
我写的串口的裸板程序，运行以后，secureCRT上不能输入也没有输出，请高手们帮忙看一下原因究竟在哪里？代码如下：
1、clock.S
.globl clock_init
clock_init:
/* 1.设置LOCK_TIME */
ldr r0, =0x7E00F000/* APLL_LOCK */
ldr r1, =0x0000FFFF
str r1,
str r1, /* MPLL_LOCK */
str r1, /* EPLL_LOCK */
#define OTHERS 0x7e00f900
@ set async mode/* 当CPU时钟 != HCLK时，要设为异步模式 */
ldr r0, =OTHERS
ldr r1,
bic r1, r1, #0xc0 /* 1100,0000 */
str r1,
loop1: /* 等待，直到CPU进入异步模式 */
ldr r0, =OTHERS
ldr r1,
and r1, r1, #0xf00
cmp r1, #0
bne loop1
/* SYNC667 */
/* MISC_CON = 0 */
#define ARM_RATIO 0 /* ARMCLK = DOUTAPLL / (ARM_RATIO + 1) */
#define HCLKX2_RATIO 1 /* HCLKX2 = HCLKX2IN / (HCLKX2_RATIO + 1) */
#define HCLK_RATIO 1 /* HCLK = HCLKX2 / (HCLK_RATIO + 1) */
#define PCLK_RATIO 3 /* PCLK = HCLKX2 / (PCLK_RATIO + 1) */
#define MPLL_RATIO 0 /* DOUTMPLL = MOUTMPLL / (MPLL_RATIO + 1) */
ldr r0, =0x7E00F020/* CLK_DIV0 */
ldr r1, =(ARM_RATIO) | (MPLL_RATIO << 4) | (HCLK_RATIO << 8) | (HCLKX2_RATIO << 9) | (PCLK_RATIO << 12)
str r1,
/* 2.配置时钟 */
/* 2.1 配置APLL */
/* 2.1.1 设置APLL
* 2.1.2 MUXAPLL
* 2.1.3 SYNC667
* 2.1.4 DIVAPLL
*/
#define APLL_CON_VAL((1<<31) | (266 << 16) | (3 << 8) | (1))
ldr r0, =0x7E00F00C
ldr r1, =APLL_CON_VAL
str r1, /* APLL_CON, FOUTAPL = MDIV * Fin / (PDIV*2^SDIV) = 266*12/(3*2^1) = 532MHz*/
/* 2.2 配置MPLL */
/* 2.2.1 设置MPLL
* 2.2.2 MUXMPLL
* 2.2.3 SYNCMUX
* 2.2.4 SYNC667
* 2.2.5 HCLKX2_RATIO
* 2.2.6 PCLK_RATIO
*/
#define MPLL_CON_VAL((1<<31) | (266 << 16) | (3 << 8) | (1))
ldr r0, =0x7E00F010
ldr r1, =MPLL_CON_VAL
str r1, /* MPLL_CON, FOUTMPL = MDIV * Fin / (PDIV*2^SDIV) = 266*12/(3*2^1) = 532MHz*/
/* 3.选择PLL的输出作为时钟源 */
ldr r0, =0x7E00F01C
ldr r1, =0x03
str r1,
mov pc, lr
2、start.S
.globl _start
_start:
/* 硬件相关的设置 : 把外设的基地址告诉CPU*/
/* Peri port setup */
ldr r0, =0x70000000
orr r0, r0, #0x13
mcr p15,0,r0,c15,c2,4 @ 256M(0x70000000-0x7fffffff)
/* 关看门狗 */
/* 往WTCON(0x7E004000)写0 */
ldr r0, =0x7E004000
mov r1, #0
str r1,
/*设置时钟 */
bl clock_init
/* 设置栈, 调用C函数 */
ldr sp, =0x0c002000
bl main
halt:
b halt
3、uart.c
#define ULCON0 (*((volatile unsigned long *)0x7F005000))
#define UCON0 (*((volatile unsigned long *)0x7F005004))
#define UFCON0 (*((volatile unsigned long *)0x7F005008))
#define UMCON0 (*((volatile unsigned long *)0x7F00500C))
#define UTRSTAT0 (*((volatile unsigned long *)0x7F005010))
#define UFSTAT0 (*((volatile unsigned long *)0x7F005018))
#define UTXH0 (*((volatile unsigned char *)0x7F005020))
#define URXH0 (*((volatile unsigned char *)0x7F005024))
#define UBRDIV0 (*((volatile unsigned short *)0x7F005028))
#define UDIVSLOT0(*((volatile unsigned short *)0x7F00502C))
#define GPACON (*((volatile unsigned long *)0x7F008000))
void init_uart(void)
{
GPACON &= ~0xff;
GPACON |= 0x22;
/* ULCON0 */
ULCON0 = 0x3;/* 数据位:8, 无较验, 停止位: 1, 8n1 */
UCON0= 0x5;/* 使能UART发送、接收 */
UFCON0 = 0x01; /* FIFO ENABLE */
UMCON0 = 0;/*流量控制*/
/* 波特率 */
/* DIV_VAL = (PCLK / (bps x 16 ) ) - 1
* bps = 115200
* DIV_VAL = (66500000 / (115200 x 16 ) ) - 1
* = 35.08
*/
UBRDIV0 = 35;
/* x/16 = 0.08
* x = 1
*/
UDIVSLOT0 = 0x1;
}
char getchar(void)
{
while ((UFSTAT0 & 0x7f) == 0);/* 如果RX FIFO空，等待 */
return URXH0; /* 取数据 */
}
void putchar(char c)
{
while (UFSTAT0 & (1<<14)); /* 如果TX FIFO满，等待 */
UTXH0 = c; /* 写数据 */
}
4、main.c
#include "uart.h"
int main()
{
char c;
init_uart();
while (1)
{
c = getchar();
putchar(c+1);
}
return 0;
}
5、Makefile
uart.bin: start.o main.o uart.o clock.o
arm-linux-ld -Ttext 0x0c000000 -o uart.elf $^
arm-linux-objcopy -O binary uart.elf uart.bin
arm-linux-objdump -D uart.elf > uart.dis
%.o : %.S
arm-linux-gcc -o $@ $< -c
%.o : %.c
arm-linux-gcc -o $@ $< -c
clean:
rm *.o uart.elf uart.bin uart.dis
C:\Documents and Settings\Administrator\桌面\新建文件夹 检查下CRT上的串口设置有没有取消流控 取消了的，还是不行。
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