uarts裸機程式

硬體平台：jz2440

實現功能：向串列埠軟體實現輸出putchar函式

start.s   --> 設定堆疊，關閉看門狗，初始化時鐘，初始化sdram

init.c      -->初始化函式

uart.c    -->初始化串列埠暫存器

uart.h    -->

main.c  -->

start.s原始碼：

.extern

main
.text
.global
_start
_start:
ldr sp,=4096
bl watchdog_init
bl clock_init
bl sdram_init 
bl copy_steppingstone_to_sdram
ldr pc,=sdram
sdram:
ldr sp,=0x34000000
ldr lr,=main_return
ldr pc,=main 
main_return:
b main_return

init.c 原始碼：

//

watchdog
#define wtcon (*(volatile unsigned long *)0x53000000)
//clock 
#define locktime (*(volatile unsigned long *)0x4c000000)
#define mpllcon (*(volatile unsigned long *)0x4c000004)
#define clkdivn (*(volatile unsigned long *)0x4c000014)
//sdram 
#define bwscon (*(volatile unsigned long *)0x48000000)
#define bankcon0 (*(volatile unsigned long *)0x48000004)
#define bankcon1 (*(volatile unsigned long *)0x48000008)
#define bankcon2 (*(volatile unsigned long *)0x4800000c)
#define bankcon3 (*(volatile unsigned long *)0x48000010)
#define bankcon4 (*(volatile unsigned long *)0x48000014)
#define bankcon5 (*(volatile unsigned long *)0x48000018)
#define bankcon6 (*(volatile unsigned long *)0x4800001c)
#define bankcon7 (*(volatile unsigned long *)0x48000020)
#define refresh (*(volatile unsigned long *)0x48000024)
#define banksize (*(volatile unsigned long *)0x48000028)
#define mrsrb6 (*(volatile unsigned long *)0x4800002c)
#define mrsrb7 (*(volatile unsigned long *)0x48000030)
void watchdog_init(void
)void clock_init(void
)void sdram_init(void
)void copy_steppingstone_to_sdram(void
)}

uart.c 原始碼：

//

uart 
#define ulcon0 (*(volatile unsigned long *)0x50000000)
#define ucon0 (*(volatile unsigned long *)0x50000004)
#define ufcon0 (*(volatile unsigned long *)0x50000008)
#define umcon0 (*(volatile unsigned long *)0x5000000c)
#define utrstat0 (*(volatile unsigned long *)0x50000010)
#define uerstat0 (*(volatile unsigned long *)0x50000014)
#define utxh0 (*(volatile unsigned char *)0x50000020)
#define urxh0 (*(volatile unsigned char *)0x50000024)
#define ubrdiv0 (*(volatile unsigned long *)0x50000028)
//gph
#define gphcon (*(volatile unsigned long *)0x56000070)
#define gphdat (*(volatile unsigned long *)0x56000074)
#define gphup (*(volatile unsigned long *)0x56000078)
void uart0_init(void
)unsigned 
char getc(void
)void putc(unsigned char
date)

uart.h 原始碼：

#ifndef _uart_h_ 

#define _uart_h_ 
void uart0_init(void
);unsigned 
char getc(void
);void putc(unsigned char
date);
#endif

main.c 原始碼：

#include"

uart.h
"int main(void
)

連線指令碼uart.lds ：

sections

.rodata : 
.dtat : 
.bss : 
}

makefile:

objs:=start.o init.o uart.o main.o 

uart.bin:$(objs)
arm-linux-ld -tuart.lds -o uart_elf $^arm-linux-objcopy -o binary -s uart_elf $@
arm-linux-objdump -d -m arm uart_elf >uart.dis
%.o:%.s
arm-linux-gcc -o $@ -c $<
%.o:%.c
arm-linux-gcc -o $@ -c $rm -f *.o *.bin *.dis uart_elf

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