【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

15.4.1Touch 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);

15.4.2SPI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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