Cortex A8 LED 点亮程序分析

1 Cortex A8 LED 点亮程序分析

1.1 环境搭建准备工作

软件环境： 1.下载eclipse软件(绿色软件)

2. 安装“yagarto-bu-2.22_gcc-4.7.1-c-c++_nl-1.20.0_gdb-7.4.1_eabi_20120616.exe”

3. tftpd32.exe

硬件平台： FS_S5PC100

搭建硬件环境： 1.PC UART-->开发板串口COM1(通过串口线)

2. 电脑网卡-->开发板网卡(通过网线)

1.2 启动Eclipse 软件，导入已有LED project

1.3 Makefile 文件分析

红色字体必须根据实际安装路径和项目路径细微修改

# CORTEX-A8 PERI DRIVER CODE

# VERSION 1.0

# ATHUOR lapset (klapset@gmail.com)

# MODIFY DATE

# 2012.2.22 by lapset ,to change the format of Makefile

#NOTE :please fix the following info to adpat to your environment

CROSS_COMPILE=arm-none-eabi-

LDPATH="C:\Program Files\yagarto\lib\gcc\arm-none-eabi\4.7.1\include"

OUTPATH="G:\tftp"

NAME=led

COMMONPATH = "G:\ARM\example modify\led_FS_S5PC100\common\include"

#=============================================================================#

#DO NOT TO CHANG THE CODE AFTER THIS !!!

export CFLAGS LD CC STRIP OBJCOPY OBJDUMP COMMONPATH

CFLAGS += -g -O0 -fno-strict-aliasing -mabi=apcs-gnu -mfpu=vfpv3 -mfloat-abi=softfp -fno-builtin -nostdinc -isystem $(LDPATH) -I $(COMMONPATH)

LD = $(CROSS_COMPILE)ld

CC = $(CROSS_COMPILE)gcc

STRIP = $(CROSS_COMPILE)strip

OBJCOPY = $(CROSS_COMPILE)objcopy

OBJDUMP = $(CROSS_COMPILE)objdump

OBJS := start/start.o common/src/printf.o common/src/uart.o common/src/_udivsi3.o common/src/_umodsi3.o $(NAME).o

SUBDIRS := common/src/ start/

all:$(SUBDIRS)$(OBJS)

$(LD) $(OBJS) -Tmap.lds -o $(NAME).elf

$(OBJCOPY) -O binary $(NAME).elf $(NAME).bin

$(OBJDUMP) -D $(NAME).elf > $(NAME).dis

cp ./$(NAME).bin $(OUTPATH)

$(SUBDIRS):

$(MAKE) -C $@

%.o: %.S

$(CC)$(CFLAGS) -c -o $@ $<

%.o: %.c

$(CC)$(CFLAGS) -c -o $@ $<

clean:

rm -rf $(OBJS) *.elf *.bin *.dis $(OUTPATH)/$(NAME).bin

1.4 Build project 生成led.bin 文件

1. 鼠标右击project name，选择“Build Project”

2. 成功后，会在该目录下【OUTPATH="G:\tftp"】生成led.bin文件，

如下所示,将tftpd32.exe和led.bin放在同一个目录下

1.5 配置ip地址

1. 让开发板上电，进入uboot

2. 输入pri 打印环境变量，使用setenv 命令来修改参数，让ip和PC ip地址保持一致

3. Ping ip地址，显示alive字样，表示网络连接OK

4. 打开PC上的tftpd32.exe 软件，设置好对应的ip地址

5.执行tftp 下载led.bin到内存0x20008000地址处，然后运行该程序”go 20008000”