linux下74lv164驱动3LED数码管

板子上使用了74lv164作为io的串行并处的扩展来驱动3个数码管LED。原理图如下

从两张图可以阐述链接的io顺序不是你想的那样有规律，因此需要做个表格来
分别将0…9的数据段统计出来

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define DEVICE_NAME “led”

include “74LV164.h”

//#define debug

/*
CPU Board s3c6410
samsung s3c6410 74lv164
GPI0 7SEG_CLK 57
GPI2 7SEG_DATA 61
GPI4 7SEG_CLR 59
*/

unsigned char data[]={0xc0,0xcf,0x64,0x46,0x4b,0x52,0x50,0xc7,0x40,0x42,0x41};//led 0,1,…9

void init_74lv764_port(void){

unsigned int reg_value;__raw_writel(0x55555555,S3C64XX_GPICON);PORTI=0xFFFFFFFF;__raw_writel(0xFFFFFFFF,S3C64XX_GPIDAT);printk("S3C64XX_GPIDAT %08x",__raw_readl(S3C64XX_GPIDAT));printk("S3C64XX_GPICON %08x",__raw_readl(S3C64XX_GPICON));reg_value=readl(S3C64XX_GPICON);reg_value=(reg_value & (~((0x03 << 0 )| (0x03 << 2 )| (0x03 <<4 ))));//port0,port2,port4 reg_value |= ((0x01 << 0 )| (0x01 << 2 )| (0x01 <<4 ));//set port 0,2,4 outputwritel(reg_value,S3C64XX_GPICON);CLR_1;DI_1;CLK_1;

}

void delay_ms(UI16_T Counter){
while(Counter–);

}

/*
* Loads a byte into the shift register (74’164).
*
* Parameters:
* out_byte The byte to load into the ‘164.
*/
void
led_load_byte(uint8_t out_byte)
{
/* make sure clock is low */
CLK_0;

    int i;    for(i=0; i<8; i++)    {            /* loop through bits */            if (out_byte & 0x80)            {                    /* this bit is high */                    DI_1;             }            else            {                    /* this bit is low */                    DI_0;            }            out_byte = out_byte << 1;            /* pulse the the shift register clock */            CLK_1;            delay_ms(20000);            CLK_0;    }

}

ssize_t s3c6410_led_write(struct file *filp,const char __user *buf,size_t dontcare,loff_t *f_pos){

return 1;

}

static long s3c6410_led_ioctl(struct file *filp, unsigned int cmd, unsigned long arg){

return 0;

}

static struct file_operations dev_fops = {
.owner = THIS_MODULE,
.unlocked_ioctl = s3c6410_led_ioctl,
.write = s3c6410_led_write,
};

static struct miscdevice misc = {
.minor = MISC_DYNAMIC_MINOR,
.name = DEVICE_NAME,
.fops = &dev_fops,
};

static int __init dev_init(void){
int ret;
int i;
unsigned char address[6];
init_74lv764_port();

for(i=0;i<11;i++){    led_load_byte(data[i]);    mdelay(2000);}ret = misc_register(&misc);printk (DEVICE_NAME"\t initialized \n");return ret;

}

static void __exit dev_exit(void){
misc_deregister(&misc);
writel(0x00,S3C64XX_GPIDAT);
printk (DEVICE_NAME “\tdev_exit\n”);
}

module_init(dev_init);
module_exit(dev_exit);
MODULE_LICENSE(“GPL”);
MODULE_AUTHOR(“gary Inc.”);
简单测试了下，在insmod 下循环送出LED数