【GD32H757Z海棠派开发板使用手册】第十五讲 TFT-8080电阻屏屏触摸实验

15.1 实验内容

通过本实验主要学习以下内容：

• LCD触控原理
• SPI外设功能

15.2 实验原理

本实验介绍通过SPI接口控制8080接口屏的touch功能。

15.3 硬件设计

8080接口屏touch部分实现如下图所示，通过SPI接口进行实现。

15.4 代码解析

15.4.1 Touch SPI定义

Touch 的SPI定义如下所示：

JSON //定义TOUCH_SPI SPI_MASTER_SCK_GPIO_DEF(TOUCH_SPI,B,3,GPIO_AF_5); SPI_MASTER_MOSI_GPIO_DEF(TOUCH_SPI,B,5,GPIO_AF_5); SPI_MASTER_MISO_GPIO_DEF(TOUCH_SPI,B,4,GPIO_AF_5); SPI_MASTER_CS_GPIO_DEF(TOUCH_SPI,A,8); SPI_TX_DMA_DEF(TOUCH_SPI,SPI0,DMA1,DMA_CH1); SPI_RX_DMA_DEF(TOUCH_SPI,SPI0,DMA1,DMA_CH0); SPI_DEF(TOUCH_SPI,SPI0,SPI_MASTER,SPI_DATASIZE_8BIT,SPI_CK_PL_LOW_PH_1EDGE,SPI_PSC_64,SPI_ENDIAN_MSB,MODE_POLL);

15.4.2 SPI初始化配置

Touch SPI初始化配置如下所示：

JSON void bsp_spi_init(typdef_spi_struct *spix) {     driver_spi_init(spix); }

15.4.3 屏幕touch状态获取函数

屏幕touch状态获取函数如下所示，通过该函数可扫描获取touch位置。

JSON Drv_Err bsp_touch_scan(uint16_t *x, uint16_t *y) {     static uint8_t count=0;     uint16_t touch_ad_x,touch_ad_y = 0;     /* touch pen is active */     if (SET == bsp_touch_pen_irq())     {            if(++count>=20 || lcd_touch_panel_struct.TOUCH_State==1)         {             lcd_touch_panel_struct.TOUCH_State=1;             if((SUCCESS != bsp_touch_ad_xy_get(&touch_ad_x, &touch_ad_y))){                 return DRV_ERROR;              }         //            if(invalid_count >= 20){  //                return DRV_ERROR; //            }                    }else         {             return DRV_ERROR;         }             }else{          count=0;         if(lcd_touch_panel_struct.TOUCH_State==1){             lcd_touch_panel_struct.TOUCH_State=2;             lcd_touch_panel_struct.Touch_x_Last=*x;             lcd_touch_panel_struct.Touch_y_Last=*y;                      }         return DRV_ERROR;     }          *x=bsp_touch_coordinate_x_get(touch_ad_x);      *y=bsp_touch_coordinate_y_get(touch_ad_y);       if(count==20)     {         lcd_touch_panel_struct.TOUCH_State=1;                lcd_touch_panel_struct.Touch_x_First=*x;         lcd_touch_panel_struct.Touch_y_First=*y;                      }     lcd_touch_panel_struct.Touch_x_Now=*x;     lcd_touch_panel_struct.Touch_y_Now=*y;                 return DRV_SUCCESS; }

15.4.4 主函数

本例程主函数如下所示，在本例程中，8080液晶屏上显示4个LED图标，通过触控点到哪个LED，MCU检测到后打开对应的LED灯。

JSON int main(void) {     uint16_t num[4]={0,0,0,0}; /* store the touch point number on four buttons */     uint8_t count=0;     char* led_string[4]={"LED1","LED2","LED3","LED4"} ;     uint8_t button_id=0;          driver_init();       /* 延时和公共驱动部分初始化 */     bsp_8080_lcd_init();                 /* 初始化LCD */       bsp_led_group_init();         //初始化SPI         bsp_spi_init(&TOUCH_SPI);          /* configure the GPIO of SPI touch panel */     bsp_touch_panel_init(bsp_8080_lcd_parameter.width,bsp_8080_lcd_parameter.height);     delay_ms(50);       /* clear the LCD screen */     bsp_8080_lcd_clear(WHITE);     bsp_8080_lcd_show_log();              bsp_8080_lcd_show_string(a1+30, b1+80,bsp_8080_lcd_parameter.width,FONT_ASCII_24_12,FONT_ASCII_24_12,led_string[0],BLUE);             /* draw picture of button on LCD screen */     bsp_8080_lcd_color_fill(a1+30,b1+40,a1+30+40-1,b1+40+40-1,(uint16_t *)(image_off + BMP_HEADSIZE));     bsp_8080_lcd_show_string(a2+30, b1+80,bsp_8080_lcd_parameter.width,FONT_ASCII_24_12,FONT_ASCII_24_12,led_string[1],BLUE);             bsp_8080_lcd_color_fill(a2+30,b1+40,a2+30+40-1,b1+40+40-1,(uint16_t *)(image_off + BMP_HEADSIZE));          bsp_8080_lcd_show_string(a1+30, b2+80,bsp_8080_lcd_parameter.width,FONT_ASCII_24_12,FONT_ASCII_24_12,led_string[2],BLUE);             bsp_8080_lcd_color_fill(a1+30,b2+40,a1+30+40-1,b2+40+40-1,(uint16_t *)(image_off + BMP_HEADSIZE));          bsp_8080_lcd_show_string(a2+30, b2+80,bsp_8080_lcd_parameter.width,FONT_ASCII_24_12,FONT_ASCII_24_12,led_string[3],BLUE);                 bsp_8080_lcd_color_fill(a2+30,b2+40,a2+30+40-1,b2+40+40-1,(uint16_t *)(image_off + BMP_HEADSIZE));     while(1){         /* get the position of touch on LCD screen */         if(DRV_SUCCESS == bsp_touch_scan(&touch_x,&touch_y)){             count++;                   get_touch_area(touch_x,touch_y,num);         }         else         {             count=0;         }         /*  generate response to the touch(turn on LED and change picture )*/         if(count==10){             button_id = find_max(num);             turn_on_led(button_id);             change_picture(button_id);             num[0]=num[1]=num[2]=num[3]=0;             count=0;         }     } }

15.5 实验结果

将本例程烧录到海棠派开发板中，通过手指点击屏幕上的LED图标，可以点亮对应的LED.

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