DMA 串口

串口数据分段收到，这种情况如何用DMA方式接收？

发布于 2022-06-21 16:33:42 浏览：956 订阅该版

lqwuliang 2022-06-21

天下没有解决不了的bug，只有发现不了的bug.

DuBaojun 2022-06-21

这家伙很懒，什么也没写！

lqwuliang 2022-06-22

天下没有解决不了的bug，只有发现不了的bug.

伊森亨特 2022-07-25

这家伙很懒，什么也没写！

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7 个回答

红枫认证专家 2022-06-21

这家伙很懒，什么也没写！

出出啊 2022-06-21

恃人不如自恃，人之为己者不如己之自为也

出出啊 2022-06-21

恃人不如自恃，人之为己者不如己之自为也

DuBaojun 2022-06-22

这家伙很懒，什么也没写！

出出啊 2022-06-22

恃人不如自恃，人之为己者不如己之自为也

DuBaojun 2022-06-24

这家伙很懒，什么也没写！

出出啊 2022-06-24

恃人不如自恃，人之为己者不如己之自为也

出出啊 2022-06-24

恃人不如自恃，人之为己者不如己之自为也

DuBaojun 2022-06-28

这家伙很懒，什么也没写！

出出啊 2022-06-28

恃人不如自恃，人之为己者不如己之自为也

伊森亨特 2022-07-25

这家伙很懒，什么也没写！

出出啊 2022-07-25

恃人不如自恃，人之为己者不如己之自为也

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lchnu 2022-06-21

Witness, Understand, Skill

swet123 2022-06-22

ztlchina@foxmail.com

这个看来是串口屏的吧？直接给你代码

```
enum lcdCMDProcessStatus
{
    LCDPSTATUS_FINDHEAD1 = 0,
    LCDPSTATUS_FINDHEAD2 = 1,
    LCDPSTATUS_LEN,
    LCDPSTATUS_CMD,
    LCDPSTATUS_DATA,
};

typedef struct
{
    rt_device_t   dev;
    struct rt_semaphore  r_tx;
    rt_uint8_t buff[Screen_BUFF_SIZE];
    rt_uint8_t buff_len;
    rt_uint8_t r_sta;
    rt_uint8_t errtime;
} Screen_DEV ;

static Screen_DEV  ScreenDev;

ALIGN(RT_ALIGN_SIZE)
static rt_uint8_t sc_read_stack[ 1024 ];
static struct rt_thread sc_read_thread;
void Screen_process(void* s)
{
    RT_ASSERT(ScreenDev.dev);

u8 ch = 0;

rt_kprintf("scree process thread running...\r\n");

/* 清空接收参数.,做接收准备 */
    ScreenDev.r_sta = LCDPSTATUS_FINDHEAD1;
    ScreenDev.buff_len = 0;
    rt_memset(ScreenDev.buff, 0, Screen_BUFF_SIZE);

while (1)
    {
        if ((rt_sem_take(&ScreenDev.r_tx, 50)) != RT_EOK)
        {
            continue;
        }

/* read one character from device */
        while (rt_device_read(ScreenDev.dev, 0, &ch, 1) == 1)
        {
            lcd_cmd_analyse(ch);
        }

rt_thread_delay(40);
    }
}

void  lcd_cmd_analyse(u8 c)
{
    static u8 len = 0;
    static u8 index = 0;

switch (ScreenDev.r_sta)
    {
        case  LCDPSTATUS_FINDHEAD1:
            if (c != 0x5A)
                break;
            len = 0;
            ScreenDev.buff_len = 0;
            ScreenDev.buff[ScreenDev.buff_len++] = c;
            ScreenDev.r_sta = LCDPSTATUS_FINDHEAD2;
            break;
        case  LCDPSTATUS_FINDHEAD2:
            if (c != 0xA5)
            {
                ScreenDev.r_sta = LCDPSTATUS_FINDHEAD1;
                break;
            }

ScreenDev.buff[ScreenDev.buff_len++] = c;
            ScreenDev.r_sta = LCDPSTATUS_LEN;
            break;
        case LCDPSTATUS_LEN:
            len = c;
            index = 0;
            ScreenDev.buff[ScreenDev.buff_len++] = len;
            ScreenDev.r_sta = LCDPSTATUS_CMD;
            if (len < 3)
                ScreenDev.r_sta = LCDPSTATUS_FINDHEAD1;
            break;
        case LCDPSTATUS_CMD:
            if (c != 0x80 && c != 0x81 && c != 0x82 && c != 0x83 && c != 0x84)
            {
                ScreenDev.r_sta = LCDPSTATUS_FINDHEAD1;
                break;
            }
            ScreenDev.buff[ScreenDev.buff_len++] = c;
            index++;
            ScreenDev.r_sta = LCDPSTATUS_DATA;
            break;
        case LCDPSTATUS_DATA:
            ScreenDev.buff[3 + index] = c;
            ScreenDev.buff_len++;
            index++;
            if (index == len)
            {
#ifdef USING_LCD_CRC
                if (CRC16(ScreenDev.buff + 3, index) == 0)
                {
                    Screen_Analyze(ScreenDev.buff);
                }
                else
                    rt_kprintf("[LCD]: Recv from lcd, but crc error.\n");
#else
                rt_kprintf("get one screen cmd.\r\n");
                debug_sendbuff(ScreenDev.buff, len + 3);
                Screen_Analyze(ScreenDev.buff);
#endif
            }
            else
            {
                break;
            }

ScreenDev.r_sta = LCDPSTATUS_FINDHEAD1;
            break;
        default:
            ScreenDev.r_sta = LCDPSTATUS_FINDHEAD1;
            break;
    }
}

typedef struct  _LCD_COMMU_PARA
{
    rt_uint8_t begain[2];       //5a  a5
    rt_uint8_t len;             //长度
    rt_uint8_t cmd;             //命令
    union
    {
        rt_uint8_t data[256];
        struct
        {
            rt_uint8_t reg;
            word len;
            rt_uint8_t year;
            rt_uint8_t month;
            rt_uint8_t day;
            rt_uint8_t week;
            rt_uint8_t hour;
            rt_uint8_t min;
            rt_uint8_t sec;
        } lcd_time;
        struct
        {
            rt_uint16_t reg;
            rt_uint8_t  regnum;
            rt_uint8_t regdata[1];
        } txt_regvalue;
        struct
        {
            rt_uint16_t reg;
            rt_uint8_t  regnum;
            rt_uint16_t regdata[1];
        } num_regvalue;
        struct
        {
            rt_uint16_t reg;
            rt_uint8_t  regnum;
            rt_uint32_t regdata[1];
        } num_regLongvalue;

struct cmd82
        {
            rt_uint8_t begainreg1;
            rt_uint8_t begainreg2;
            union {
                rt_uint8_t dat[250];
                PP_HeadLine1    page_HeadLine1; 
            }cmd82dat;
        } cmd82;
    } data_area;
} LCD_COMMU_PARA;

void Screen_Analyze(u8* _buf)
{
#if 1
    static SCREEN_PAGE_CHOSE oldpage = SCREEN_PAGE_Logo;
    uint16_t  presskeyid = 0;           //按键返回的按键ID
    uint16_t  getvalue  = 0;

LCD_COMMU_PARA* reply = (LCD_COMMU_PARA*)_buf;

//    if (reply->cmd == 0x81) //只有时间设置才返回81，因为使用的是屏幕上的RTC
    //    {
    //        switch (reply->data_area.lcd_time.reg) {
    //        case 0x20:
    ////            analyse_lcd_time(reply);
    //            break;
    //        default:
    //            break;
    //        }
    //    }
    //    else
    if (reply->cmd == 0x83)
    {
	}
}

```