nuc972開發詳解

一、nuc972 spi

nuc972是一款基於ARM926EJ-S內核的嵌入式高性能開發板，支持SPI介面，可以實現與SPI設備的通信。以下是SPI模式讀寫的代碼示例：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <linux/spi/spidev.h>

static const char *dev = "/dev/spidev0.0";
static uint8_t mode = 0;
static uint8_t bits = 8;
static uint32_t speed = 500000;
static uint16_t delay = 0;

int main(int argc, char *argv[])
{
    int fd, ret;
    uint8_t tx[3];
    uint8_t rx[3];

    fd = open(dev, O_RDWR);
    if (fd < 0)
    {
        perror("open");
        return 1;
    }

    ret = ioctl(fd, SPI_IOC_WR_MODE, &mode);
    if (ret == -1)
    {
        perror("can't set spi mode");
        return 1;
    }

    ret = ioctl(fd, SPI_IOC_WR_BITS_PER_WORD, &bits);
    if (ret == -1)
    {
        perror("can't set bits per word");
        return 1;
    }

    ret = ioctl(fd, SPI_IOC_WR_MAX_SPEED_HZ, &speed);
    if (ret == -1)
    {
        perror("can't set max speed hz");
        return 1;
    }

    memset(tx, 0, sizeof(tx));
    memset(rx, 0, sizeof(rx));

    tx[0] = 0x9f;

    struct spi_ioc_transfer tr =
    {
        .tx_buf = (unsigned long)tx,
        .rx_buf = (unsigned long)rx,
        .len = 3,
        .delay_usecs = delay,
        .speed_hz = speed,
        .bits_per_word = bits,
    };

    ret = ioctl(fd, SPI_IOC_MESSAGE(1), &tr);
    if (ret < 1)
    {
        perror("can't send spi message");
        return 1;
    }

    for (int i = 0; i < 3; i++)
    {
        printf("%02x ", rx[i]);
    }
    printf("\n");

    close(fd);

return status;
}

以上代碼為nuc972讀取SPI設備的代碼示例，通過SPI介面讀取設備數據。其中dev是SPI介面的設備文件名，spi_ioc_transfer結構體中初始化了發送和接收緩衝區，以及SPI的參數。

二、nuc972 8720

nuc972 8720是nuc972系列中一款常用的晶元，以下是用nuc972 8720編寫的二進位文件燒寫的代碼示例：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>

#define FILENAME "nuc972.bin"
#define MEM_DEV  "/dev/mem"

static unsigned int Nuc_Phy_Addr = 0x00;
static unsigned int Nuc_Virt_Addr = 0x00;
static unsigned int Nuc_Size = 0x00;

int main(int argc, char *argv[])
{
    int fd, fdbin, ret;
    unsigned long offset;
    char *bin_buf;
    void *mem_ptr;

    fdbin = open(FILENAME, O_RDONLY);
    if (fdbin < 0)
    {
        printf("open %s error, %s\n", FILENAME, strerror(errno));
        return -1;
    }

    fd = open(MEM_DEV, O_RDWR | O_SYNC);
    if (fd < 0)
    {
        printf("open %s error, %s\n", MEM_DEV, strerror(errno));
        return -1;
    }

    bin_buf = malloc(BIN_SIZE);
    if (bin_buf == NULL)
    {
       printf("malloc failed\n");
       return -1;
    }

    memset(bin_buf, 0, BIN_SIZE);

    ret = read(fd, bin_buf, BIN_SIZE);
    if (ret != BIN_SIZE)
    {
        printf("read %s error, %s\n", FILENAME, strerror(errno));
        return -1;
    }

    mem_ptr = mmap(0, BIN_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, fd, Nuc_Phy_Addr);
    if (mem_ptr == MAP_FAILED)
    {
        printf("mmap failed, %s\n", strerror(errno));
        return -1;
    }

    memcpy(mem_ptr + Nuc_Virt_Addr, bin_buf, BIN_SIZE);

    munmap(mem_ptr, BIN_SIZE);

    close(fd);
    close(fdbin);

    return 0;
}

以上代碼為將二進位文件nuc972.bin燒寫到nuc972 8720晶元的程序中。代碼通過打開/dev/mem設備，然後將nuc972.bin讀入內存緩衝區，再將其映射到nuc972 8720的物理地址上，修改虛擬地址的內容為bin_buf。最後釋放映射區和關閉設備文件。

三、NUC972DF71YC

NUC972DF71YC是一款低功耗、高性能的嵌入式開發板。以下是通過NUC972DF71YC串口的代碼示例：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <termios.h>

static int fd;

int open_port(void)
{
    fd = open("/dev/ttyS1", O_RDWR | O_NOCTTY | O_NDELAY);
    if (fd < 0)
    {
        printf("open ttyS1 failed\n");
        return -1;
    }

    struct termios options;
    tcgetattr(fd, &options);
    options.c_cflag = B115200 | CS8 | CLOCAL | CREAD;
    options.c_iflag = 0;
    options.c_oflag = 0;
    options.c_lflag = 0;
    tcflush(fd, TCIFLUSH);
    tcsetattr(fd, TCSANOW, &options);

    return fd;
}

int main(int argc, char *argv[])
{
    open_port();

    int ret;
    char *send_buf = "hello from nuc972\r\n";
    char recv_buf[50];

    ret = write(fd, send_buf, strlen(send_buf));
    printf("send: %s\n", send_buf);

    usleep(10000);

    ret = read(fd, recv_buf, sizeof(recv_buf));
    printf("recv: %s\n", recv_buf);

    close(fd);

    return 0;
}

以上代碼為nu972串口通信的代碼示例，程序中定義了UART的屬性，並利用串口傳輸數據。首先打開串口設備文件，通過tcgetattr()函數獲取串口屬性，再通過tcsetattr()函數設置串口屬性。然後通過read()和write()函數進行串口通信。最後關閉串口設備文件。

四、NUC972什麼時候發布

NUC972是由國內知名晶元設計公司——翱捷科技開發的具有國際水平的高性能晶元。該晶元於2015年12月發布，經過多年的市場檢驗，已經成為嵌入式領域中的重要晶元之一。