ARM day7 day8 UART串口、PWM蜂鸣器、WDT看门狗、ADC数模转换

一、串口编程

1.看原理图

|---------------------------|
| GPA1_0: RXD2 GPA1_1: TXD2 |

2.看芯片手册

3.编程

uart.c

cpp 复制代码

    		#define GPA1CON (*((volatile unsigned int *)0x11400020))
    		#define ULCON2 (*((volatile unsigned int *)0x13820000))
    		#define UCON2 (*((volatile unsigned int *)0x13820004))
    		#define UTRSTAT2 (*((volatile unsigned int *)0x13820010))
    		#define UBRDIV2 (*((volatile unsigned int *)0x13820028))
    		#define UFRACVAL2 (*((volatile unsigned int *)0x1382002C))
    		#define UTXH2 (*((volatile unsigned int *)0x13820020))
    		#define URXH2 (*((volatile unsigned int *)0x13820024))
    		
    		void uart_init(void) //初始化
    		{
    			//1.对外设置 (GPIO)
				GPA1CON &= ~0xff;  
				GPA1CON |= 0x22; //3:0->0x2(RXD2)  7:4->0x2(TXD2)	
            	//2.对内设置(uart)
                ULCON2 =  0x3;//8 1 无
                UCON2 &= ~0xf; 
                UCON2 |= 0x5; // 1:0->01(polling)  3:2->01(polling)
                UBRDIV2 = 53;
                UFRACVAL2 = 4;//波特率：115200
    		}
    		
    		void putc(char ch)
    		{
    			UTXH2 = ch;//发送数据
    			while((UTRSTAT2 & 0x2) == 0);//等待发送完成
    		}
    		
    		void puts(char *str)//一个一个发
    		{
    			while(*str)
    			{
    				putc(*str);
    				str++;
    			}
    		}
    		
    		char getc(void)
    		{
  				char ch;
    			while((UTRSTAT2 & 0x1) == 0);//等待接收缓冲区有数据
    			ch = URXH2;//接收数据
    		}
         void put_int(int num)
         {
             char buf[100];
             int i = 0;
             if (0 == num)
                 buf[i++] = '0';
             while (num) {
                 buf[i] = num % 10 + '0';
                 i++;
                 num = num / 10;
             }
             int j, k;
             for (j=0,k=i-1; j < k; j++,k--) {
                 char c = buf[j];
                 buf[j] = buf[k];
                 buf[k] = c;
             }
             buf[i] = '\r';
             buf[i+1] = '\n';
             buf[i+2] = '\0';
             puts(buf);
         }

main.c

cpp 复制代码

    			void mydelay(int x)
    			{
    				int i = 0;
    				while(x--)
    					for(i=1000;i>0;i--);
    			
    			}
    			int main()
    			{
    				uart_init(); //初始化
    				while(1)
    				{
    					puts("hello\r\n");
    					mydelay(500);
    				}
    			
    				return 0;
    			}

练习：串口控制LED 输入0时灯亮输入1时灯灭

二、PWM

1.看原理图

|-------------------|
| GPD0_0: XpwmTOUT0 |

2.看芯片手册

3.编程

pwm.c

cpp 复制代码

#define GPD0CON (*(volatile unsigned int *)0x114000A0)
#define TCFG0 (*(volatile unsigned int *)0x139D0000)
#define TCFG1 (*(volatile unsigned int *)0x139D0004)
#define TCON (*(volatile unsigned int *)0x139D0008)
#define TCNTB0 (*(volatile unsigned int *)0x139D000C)
#define TCMPB0 (*(volatile unsigned int *)0x139D0010)

void pwm_init()
{
	//1.对外设置(GPIO)
	GPD0CON &= ~0xf;
	GPD0CON |= 0x2;//3:0->0x2(TOUT0)
	
	//2.对内设置
	TCFG0 &= ~0xff;
	TCFG0 |= 255; //第一次分频
	
	TCFG1 &= ~0xf;
	TCFG1 |= 0x4;//第二次分频

	TCNTB0 = 300;//周期值
	TCMPB0 = 150;//比较值
		
	TCON &= ~0xf;
	TCON |= 0xe;
	TCON &= ~0x2; // 0->0(关闭定时器) 1->1 1->0(manual off) 2->1(inveter on) 3->1(自动重装载)
}

void buzz_on()
{
	TCON |= 0x1; //0->1
}
void buzz_off()
{
	TCON &= ~0x1; // 0->0
}

三、看门狗定时器

0.作用

看门狗的作用就是防止程序发生死循环，或者说程序跑飞。

在系统运行以后也就启动了看门狗的计数器，看门狗就开始自动计数，如果到了一定的时间还不去清看门狗，那么看门狗计数器就会溢出从而引起看门狗中断，造成系统复位。

1.看原理图

|-----|
| 不需要 |

2.看芯片手册

|----------------------------------------------------------------------------------------------------------------------|
| WTCNT:0x10060008 3000 周期值 WTCON: 0x10060000 0->1(reset enable) 4:3->11(128分频) 5->1(WDT enable) 15:8->255 (255分频) |

3.编程

wdt.c

cpp 复制代码

#define WTCNT (*((volatile unsigned int *)0x10060008))
#define WTCON (*((volatile unsigned int *)0x10060000))
void wdt_init()
{
	WTCNT = 3000;// 周期值 1s = 1/100MHZ/(255+1)/128 * 3000
	WTCON &= ~(0xff<<8);
	WTCON |= 255 << 8; //第一次分频 255分频
	WTCON |= 0x3 << 3;//第二次分频 128
	WTCON |= 0x1; //reset enable
	WTCON |= 0x1<<5; // WDT enable
}

四、ADC数模转换

1.看原理图

|----------|
| XadcAIN3 |

2.看芯片手册

|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| ADCCON: 0x126C0000 16->1(12bit的分辨率) 15(转换完成的标志位) 14->1(分频使能) 13:6->19(分频值: 132+1) 2->0(正常模式) 1->1() 0->1(ADC start) ADCDAT:0x126C000C 转换结果 ADCMUX:0x126C001C 3:0->0x3 |

3.编程

adc.c

cpp 复制代码

#define ADCCON (*((volatile unsigned int *)0x126C0000))
#define ADCDAT (*((volatile unsigned int *)0x126C000C))
#define ADCMUX (*((volatile unsigned int *)0x126C001C))
void adc_init(void)
{
	ADCCON |= 0x1 << 16;//12bit的分辨率  15(转换完成的标志位)  
	ADCCON |= 0x1 << 14; //分频使能
	ADCCON &= ~(0xff<<6);
	ADCCON |= 132 << 6;//分频值: 132+1
	ADCCON &= ~(0x1<<2); //正常模式
	ADCCON &= ~0x2; //转换完成再去读数据

	ADCMUX &= ~0x7;
	ADCMUX |= 0x3;//AIN3
}

int readData(void)
{
	int data = 0;//保存转换之后的数字量
	int voltage = 0;//保存转换之后的电压

	ADCCON |= 0x1;//ADC使能
	while(ADCCON & (0x1<<15) == 0);//等待转换完成
	data = ADCDAT & 0xfff;//转换的数字量
	voltage = (1800 * (data+1)) / 4096;//电压值

	return voltage;

}

Makefile

perl 复制代码

all:
	arm-none-linux-gnueabi-gcc -fno-builtin -nostdinc -c -o start.o start.s
	arm-none-linux-gnueabi-gcc -fno-builtin -nostdinc -c -o main.o main.c
	arm-none-linux-gnueabi-gcc -fno-builtin -nostdinc -c -o uart.o uart.c
	arm-none-linux-gnueabi-gcc -fno-builtin -nostdinc -c -o pwm.o pwm.c
	arm-none-linux-gnueabi-gcc -fno-builtin -nostdinc -c -o wdt.o wdt.c
	arm-none-linux-gnueabi-gcc -fno-builtin -nostdinc -c -o adc.o adc.c
	arm-none-linux-gnueabi-ld start.o main.o uart.o pwm.o wdt.o adc.o -Tmap.lds -o pwm.elf
	arm-none-linux-gnueabi-objcopy -O binary pwm.elf pwm.bin
	arm-none-linux-gnueabi-objdump -D pwm.elf > pwm.dis
clean:
	rm -rf *.bak *.o *.elf *.dis *.bin

五、中断编程

|------------------------------------------------------------------------------------------------------------------------------|
| 1.理解外部设备触发的一种异常; |
| 2.好处能够让cpu及时响应外部设备的请求，即马上请求马上响应，提升的硬件的性能。 |
| 3.处理过程 1)当多个中断同时发生时，CPU如何处理？优先级 2)当cpu正在处理中断是，突然又来一个同级或低优先级的中断时，cpu如何处理？ cpu一定先处理完当前的中断，再去处理新中断； 3)中断标志位中断处理完之后一定要清除中断标志位。 |

六、按键中断编程（按一下K2 执行打印，需要用到串口）

1.看原理图

|-----------------------------|
| GPX1_1: EINT9 port:25 Id:57 |

2.看芯片手册

|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| 1)对外设置(GPIO) GPX1CON: 0x11000C20 7:4->0xF //EXT_INT41 EXT_INT41CON: 0x11000E04 6:4->0x2 //下降沿触发 EXT_INT41_MASK: 0x11000F04 1->0 //Enables Interrupt EXT_INT41_PEND: 0x11000F44 1->1 //清除GPIO中断标志位 |
| 2)对内设置(INT) ICDISER_CPU: 0x10490104 25->1 //总使能 ICDIPTR14:0x10490838 0x01010101 //分发器 ICDDCR: 0x10490000 0->1 //分发使能 ICCICR_CPU0:0x10480000 0->1 //接口使能 ICCPMR_CPU0:0x10480004 255 //优先级 ICCEOIR_CPU0: 0x10480010 9:0->写中断ID //结束中断 ICDICPR_CPU: 0x10490284 25->1 //清除GIC中断标志位 ICCIAR_CPU0: 0x1048000C 9:0->ID //获取中断ID |

3.编程

irq.c

cpp 复制代码

#include "uart.h"

#define GPX1CON 		(*(volatile unsigned int *)0x11000C20)
#define EXT_INT41CON 	(*(volatile unsigned int *)0x11000E04)
#define EXT_INT41_MASK 	(*(volatile unsigned int *)0x11000F04)
#define EXT_INT41_PEND 	(*(volatile unsigned int *)0x11000F44)    
#define ICDISER_CPU 	(*(volatile unsigned int *)0x10490104)
#define ICDIPTR14 		(*(volatile unsigned int *)0x10490838)
#define ICDDCR 			(*(volatile unsigned int *)0x10490000)
#define ICCICR_CPU0 	(*(volatile unsigned int *)0x10480000) 
#define ICCPMR_CPU0 	(*(volatile unsigned int *)0x10480004)
#define ICCEOIR_CPU0 	(*(volatile unsigned int *)0x10480010)
#define ICDICPR_CPU 	(*(volatile unsigned int *)0x10490284)
#define ICCIAR_CPU0 	(*(volatile unsigned int *)0x1048000C)

void irq_init(void)
{
	//1.对外设置(GPIO)
	GPX1CON |= 0xF << 4; //EXT_INT41
	EXT_INT41CON &= ~(0x7<<4);
	EXT_INT41CON |= 0x2<<4;//下降沿触发
	EXT_INT41_MASK &= ~(0x1<<1); //Enables Interrupt

	//2.对内设置(INT)
	ICDISER_CPU |= 0x1 << 25; //总使能 
	ICDIPTR14 = 0x01010101; //分发器
	ICDDCR |= 0x1; //分发使能
	ICCICR_CPU0 |= 0x1; //接口使能
	ICCPMR_CPU0 = 255; //优先级
}

void do_irq(void)//自定义中断处理函数
{
	//1.判断是哪个irq
	int id = ICCIAR_CPU0 & 0x3ff; //获取中断ID
	switch(id)
	{
		case 57:
			putc('i');//处理中断
			EXT_INT41_PEND |= 0x1<<1; //清除GPIO中断标志位
			ICDICPR_CPU |= 0x1<<25;  //清除GIC中断标志位
			break;
		case 58:
				break;
		default:
				break;
		}
		ICCEOIR_CPU0 &= ~0x3ff; 
		ICCEOIR_CPU0 |= id; //结束中断
}

start.s

cpp 复制代码

       .text
       		b reset	@0x00 reset 
       		ldr pc,_undef_handler		@0x04 undefine
       		ldr pc, _swi_handler @0x08 swi  pc =* _swi_handle
       		ldr pc, _prefetch_abort_handler @0x0C prefetch abort
       		ldr pc, _data_abort_handler @0x10 data abort
       		nop @保留
       		ldr pc, _irq_handler @irq 0x18
       		ldr pc, _fiq_handler @fiq 0x1c
       	_swi_handler:
			.word swi_handler
        _irq_handler:
			.word irq_handler
         _fiq_handler:
			.word _fiq_handler
       
       swi_handler:
			stmfd sp!,{r0-r12,lr}  @现场保护
            @处理
            ldmfd sp!,{r0-r12,pc}^ @cpsr=spsr
                
                
       irq_handler:
			stmfd sp!,{r0-r12,lr}  @现场保护
            @处理
            ldmfd sp!,{r0-r12,pc}^ @cpsr=spsr	
       
        reset: @reset异常的处理函数
           mov r0,#0x3
           mov r1,r0
       
       .end

main.c

cpp 复制代码

void mydelay(int x)
{
	int i = 0;
	while(x--)
		for(i=1000;i>0;i--);
}

int main()
{
	irq_init();//irq初始化
	uart_init(); //初始化

	while(1)
	{
		putc('a');
		mydelay(500);
	}

	return 0;
}