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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