時鐘設定和uart基本配置

開發板採用友善之臂的mini2440

以下**包含了uart配置，uart需要的時鐘配置，fclk：hclk：pclk = 1:2：4=200mhz：100mhz:50mhz

時鐘控制邏輯給整個晶元提供3種時鐘：fclk用於cpu核；hclk用於ahb(advanced high performance bus)匯流排上裝置(高效能模組)，比如cpu核，儲存器控制器，中斷控制器，lcd控制器，dma和usb主機模組等；pclk用於apb(advance peripheral bus)匯流排上裝置(低頻寬的周邊外設)，比如看門狗，iis，i2c，pwm定時器，mmc介面，adc，uart、gpio，rtc和spi

init.s

.equ sdram_base,
0x30000000
.text
.global _start
_start:
bl disable_watch_dog
ldr sp,
=4096
bl clock_init
bl mem_ctrl_setup
bl copy_steppingstone_to_sdram
ldr pc,
=on_sdram
on_sdram:
ldr sp,
=0x34000000
ldr pc,
=main
loop:
b loop
test:
ldr r0,
=0x56000010
ldr r1,
=0x11400
str r1,
[r0]
ldr r0,
=0x56000014
mov r1, #0
str r1,
[r0]
mov pc, lr
disable_watch_dog:
ldr r0,
=0x53000000
mov r1, #0
str r1,
[r0]
mov pc, lr
copy_steppingstone_to_sdram:
mov r0, #0
add r1, r0, #4096       @1024*4
4k byte
ldr r2,
=sdram_base1:
ldr r3,
[r0]
, #4
str r3,
[r2]
, #4
cmp r0, r1
bne 1b      @relative to pc 1 is below,
(b:below f:forward)
mov pc, lr

uart.c

#include
#define gpbcon (*(volatile int *)0x56000010)
#define gpbdat (*(volatile int *)0x56000014)
#define gphcon (*(volatile int *)0x56000070)
#define gphup (*(volatile int *)0x56000078)
#define ulcon0 (*(volatile int *)0x50000000)
#define ucon0 (*(volatile int *)0x50000004)
#define ufcon0 (*(volatile int *)0x50000008)
#define umcon0 (*(volatile int *)0x5000000c)
#define ubrdiv0 (*(volatile int *)0x50000028)
#define utxh0 (*(volatile int *)0x50000020)
#define urxh0 (*(volatile int *)0x50000024)
#define utrstat0 (*(volatile int *)0x50000010)
#define mem_ctl_base  (volatile int *)0x48000000
#define mpllcon (*(volatile int *)0x4c000004)
#define clkdivn (*(volatile int *)0x4c000014)
//#define mpllvalue ((0x11 << 12) | (0x01 << 4) | (0x00 << 0)) 測試插口回顯不正確原因未找到
#define mpllvalue ((0x5c << 12) | (0x01 << 4) | (0x02)) 
//完全手冊上的配置
void
delay
(int time)
}unsigned
char
uart_getc
(void
)void
uart_putc
(unsigned
char c)
void
clock_init()
void
mem_ctrl_setup()
intmain
(int argc,
char
*ar**)
return0;
}

makefile

.phony:clean bin: arm-linux-gcc -c init.s -o init.o arm-linux-gcc -c uart.c -o uart.o arm-linux-ld -ttext= 0x30000000 init.o uart.o -o uart arm-linux-objcopy -o binary uart uart.bin arm-linux-objdump -d -m arm uart > uart.dis clean:

rm -rf init.o uart.o uart uart.bin uart.dis

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