2018年10月12日 | Tiny210裸机之按键中断

start.S源码：

.global _start

_start:

    ldr sp, =0xD0030000  // 初始化栈，因为后面要调用C函数 

    bl clock_init                // 初始化时钟 

    bl ddr_init                   // 初始化内存 

    bl nand_init                // 初始化NAND 

    ldr r0, =0x36000000   // 要拷贝到DDR中的位置 

    ldr r1, =0x0                 // 从NAND的0地址开始拷贝 

    ldr r2, =bss_start         // BSS段的开始地址 

    sub r2,r2,r0                  // 要拷贝的大小 

    bl nand_read              // 拷贝数据 

clean_bss:

    ldr r0, =bss_start

    ldr r1, =bss_end

    mov r3, #0

    cmp r0, r1

    ldreq pc, =on_ddr

clean_loop:

    str r3, [r0], #4

    cmp r0, r1    

    bne clean_loop        

    ldr pc, =on_ddr

on_ddr:

    mrs  r0, cpsr

    bic    r0,r0,#0x1f  // 清M4~M0 

    orr    r0,r0,#0x12

    msr    cpsr,r0        // 进入irq 

    ldr sp, =0x3e000000    // 初始化普通中断模式的栈，指向内存 

    bl irq_init

    mrs  r0, cpsr

    bic    r0,r0,#0x9f  // 开总的中断开关,清M4~M0 

    orr    r0,r0,#0x10

    msr    cpsr,r0      // 进入user mode 

    ldr sp, =0x3f000000    // 初始化用户模式的栈，指向内存 

    ldr pc, =main

halt:

    b halt    

.global key_IRQ

key_IRQ:

    sub lr, lr, #4                   // 1.计算返回地址 

    stmdb sp!, {r0-r12, lr}  // 2.保护现场 

    // 3. 处理异常 

    bl do_irq

    // 4. 恢复现场 

    ldmia sp!, {r0-r12, pc}^  // ^表示把spsr恢复到cpsr 

===================================================================

irq.c源码：

#include "lib.h"

#define GPH2CON        (*(volatile unsigned int *)0xE0200C40)

#define GPH2DAT        (*(volatile unsigned int *)0xE0200C44)

#define GPH3CON        (*(volatile unsigned int *)0xE0200C60)

#define GPH3DAT        (*(volatile unsigned int *)0xE0200C64)

#define EXT_INT_2_CON        (*(volatile unsigned int *)0xE0200E08)

#define EXT_INT_3_CON        (*(volatile unsigned int *)0xE0200E0C)

#define EXT_INT_2_MASK        (*(volatile unsigned int *)0xE0200F08)

#define EXT_INT_3_MASK        (*(volatile unsigned int *)0xE0200F0C)

#define VIC0INTSELECT        (*(volatile unsigned int *)0xF200000C)

#define VIC0INTENABLE        (*(volatile unsigned int *)0xF2000010)

#define VIC0VECTADDR16        (*(volatile unsigned int *)0xF2000140)

#define VIC0ADDRESS          (*(volatile unsigned int *)0xF2000F00)

#define EXT_INT_2_PEND        (*(volatile unsigned int *)0xE0200F48)

#define EXT_INT_3_PEND        (*(volatile unsigned int *)0xE0200F4c)

int i = 0;

void do_irq(void)

{

    // 清中断 

    EXT_INT_2_PEND |= 1<<3;

    EXT_INT_3_PEND |= 1<<0;

    // 清中断向量 

    VIC0ADDRESS = 0;

    if(!(GPH2DAT & (1<<3)))

    {

        wy_printf("counter(k4) : %d \n",i++);

    }

    if(!(GPH3DAT & (1<<0)))

    {

        wy_printf("counter(K5) : %d \n",i--);

    }

}

extern void key_IRQ(void);

void irq_init(void)

{

    // 设置GPH2_3(K4),GPH3_0(K5)用于中断 

    GPH2CON |= 0xf<<12;

    GPH3CON |= 0xf<<0;

    // 设置触发方式为下降沿触发 

    EXT_INT_2_CON |= 0x2<<12;

    EXT_INT_3_CON |= 0x2<<0;

    // 使能中断(GPIO里面的) 

    EXT_INT_2_MASK &= ~(1<<3);

    EXT_INT_3_MASK &= ~(1<<0);

    // 设置为IRQ中断 

    VIC0INTSELECT &= ~(1<<16);

    // 使能中断(中断控制器里面的) 

    VIC0INTENABLE |= 1<<16;

    // 设置中断向量 

    VIC0VECTADDR16 = (int)key_IRQ;

}

==================================================================

main.c源码：

#include "command.h"

#include "clock.h"

#include "led.h"

#include "uart.h"

#include "lib.h"

#include "nand.h"

#define    CFG_PROMPT        "WY_BOOT # "    // Monitor Command Prompt    

#define    CFG_CBSIZE        256        // Console I/O Buffer Size    

char *argv[10];

int readline (const char *const prompt)

{

    char console_buffer[CFG_CBSIZE];        // console I/O buffer    

    char *buf = console_buffer;

    int argc = 0;

    int state = 0;

    //puts(prompt);

    wy_printf("%s",prompt);

    gets(console_buffer);

    while (*buf)

    {

        if (*buf != ' ' && state == 0)

        {

            argv[argc++] = buf;

            state = 1;

        }

        if (*buf == ' ' && state == 1)

        {

            *buf = '\0';

            state = 0;

        }

        buf++;    

    }

    return argc;

}

void message(void)

{

    wy_printf("\nThis bootloader support some command to test peripheral:\n");

    wy_printf("Such as: LCD, IIS, BUZZER \n");

    wy_printf("Try 'help' to learn them \n\n");    

}

int main(void)

{

    char buf[6];

    int argc = 0;

    int i = 0;

    led_init(); // 设置对应管脚为输出 

    uart_init(); // 初始化UART0 

    nand_read_id(buf);

    wy_printf("\n**********************************************************\n");

    wy_printf("                     wy_bootloader\n");

    wy_printf("                     vars: %d \n",2012);

    wy_printf("                     nand id:");

    putchar_hex(buf[0]);

    putchar_hex(buf[1]);

    putchar_hex(buf[2]);

    putchar_hex(buf[3]);

    putchar_hex(buf[4]);

    wy_printf("\n**********************************************************\n");

    while (1)

    {

        argc = readline (CFG_PROMPT);

        if(argc == 0 && i ==0)

        {

            message();

            i=1;

        }

        run_command(argc, argv);

    }

    return 0;

}

==================================================================

Makefile文件：

uart.bin:start.s main.c uart.c clock.c led.c lib.c command.c nand.c mem_setup.S irq.c

    arm-linux-gcc -nostdlib -c start.s -o start.o

    arm-linux-gcc -nostdlib -c main.c -o main.o

    arm-linux-gcc -nostdlib -c uart.c -o uart.o

    arm-linux-gcc -nostdlib -c lib.c -o lib.o

    arm-linux-gcc -nostdlib -c clock.c -o clock.o    

    arm-linux-gcc -nostdlib -c led.c -o led.o    

    arm-linux-gcc -nostdlib -c command.c -o command.o    

    arm-linux-gcc -nostdlib -c nand.c -o nand.o    

    arm-linux-gcc -nostdlib -c irq.c -o irq.o    

    arm-linux-gcc -nostdlib -c mem_setup.S -o mem_setup.o    

    arm-linux-ld -T bootloader.lds start.o main.o uart.o lib.o clock.o led.o command.o nand.o mem_setup.o irq.o -o uart_elf

    arm-linux-objcopy -O binary -S uart_elf uart.bin

clean:

    rm -rf *.o *.bin uart_elf *.dis

===================================================================

bootloader.lds链接文件：

SECTIONS {

    . = 0x36000010;

    .text : {

        * (.text)

    }

    . = ALIGN(4);

    .rodata : {

        * (.rodata)

    }

    . = ALIGN(4);

    .data : {

        * (.data)

    }

    . = ALIGN(4);

    bss_start = .;

    .bss  : { *(.bss)  *(COMMON) }

    bss_end = .;

}