linux下应用------七段数码管（一）

套件：IMX287A

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

#define SPI_DEVICE"/dev/spidev1.0"
#define GPIO_DEVICE "/sys/class/gpio/gpio117/value"   // gpio3.21的属性文件

uint8_t led_value_table[] =   {0xC0, 0xF9, 0xa4, 0xb0, 0x99, 0x92, 0x82, 0xF8, 0x80, 0x90};
static uint8_t mode = 0;
static uint8_t bits = 8;
static uint32_t speed = 10000;
static uint16_t delay = 0;

static void show_led_num(int fd_spi, int fd_gpio, int value, int num)
{
    int ret;
    uint8_t tx[] = {led_value_table[value],
                                (1 << num),
    }

    struct spi_ioc_transfer tr_txrx[] = {
        {
            .tx_buf      = (unsigned long)tx,
            .rx_buf      = 0,
            .len         = 2,
            .delay_usecs = delay,
            .speed_hz    = speed,
            .bits_per_word = bits,
        },
    };

    ret = ioctl(fd_spi, SPI_IOC_MESSAGE(1), &tr_txrx[0]);

    if (ret == 1) {
        printf("can't revieve spi message");
        return;
    }
    write(fd_gpio, "0", 1);
    usleep(100);
    write(fd_gpio, "1", 1);
}

int main(int argc, char *argv[]){
    int ret       = 0;
    int fd_spi    = 0;
    int fd_gpio   = 0;
    int led_value = 0;
    int led_num   = 0;

    if (argc !=3) {
        /* 输入参数必须为两个*/
        printf("cmd : ./spi_led_test led_value led_num \n ");
        return -1;
    }

    led_value = atoi(argv[1]);/* 获取程序输入参数的数码管的显示值*/
    if ((led_value) < 0 || (led_value > 9)) {
        /* 该值必须在0 ~ 9之间*/
        printf("led num just in 0 ~ 9 \n");
        return -1;
    }

    led_num = atol(argv[2]);/* 获取程序输入参数的数字选择值*/
    if ((led_num < 0) || (led_num > 3)) {
        /* 该值必须在0 ~ 3之间*/
        printf("led number just in 0 ~ 3");
        return -1;
    }

    fd_spi = open(SPI_DEVICE, O_RDWR);/* 打开SPI总线的设备文件*/
    if (fd_spi < 0) {
        printf("can't open %s \n", SPI_DEVICE);
        return -1;
    }

    fd_gpio = open(GPIO_DEVICE, O_RDWR);/* 打开GPIO设备的属性文件*/
    if (fd_gpio < 0) {
        printf("can't open %s device\n", GPIO_DEVICE);
        return -1;
    }

    ret = ioctl(fd_spi, SPI_IOC_WR_MODE, &mode);
    if (ret == -1) {
        printf("can't set wr spi mode\n");
        return -1;
    }

    ret = ioctl(fd_spi, SPI_IOC_WR_BITS_PER_WORD, &bits);/* 设置SPI的数据位*/
    if (ret == -1) {
        printf("can't set bits per word\n");
        return -1;
    }

    ret = ioctl(fd_spi, SPI_IOC_WR_MAX_SPEED_HZ, &speed);/* 设置SPI的最大总线频率*/
    if (ret == -1){
        printf("can't set max speed hz\n");
        return -1;
    }

    show_led_num(fd_spi, fd_gpio, led_value, led_num);

    close(fd_spi);
    return ret;
}

数码管的段选信号是gpio117即p3_21引脚，高电平有效，通过执行命令

 /sys/dev# cd /sys/class/gpio
 /sys/class/gpio# echo 117 >export                                       
 /sys/class/gpio# echo out >gpio117/direction                            

执行编译好的文件

root@EasyARM-iMX28x /mnt/nfs# ./spi_led_test 3 1

结果如图：

root@EasyARM-iMX28x /mnt/nfs# ./spi_led_test 3 0

结果如图：