6.1. SPI - TFT LCD Display

6.1.1. Hardware Connection

This demo is based on BL706_AVB, and the connection method is as follows

   GPIO function         GPIO pin
----------------------------------
    LCD_CS      <-->     GPIO10
    LCD_DC      <-->     GPIO22
    SPI_SCK     <-->     GPIO19
    SPI_MISO    <-->     GPIO20
    SPI_MOSI    <-->     GPIO21

6.1.2. Software Implementation

  • See examples/spi/spi_lcd for the software code

1#define BSP_SPI_CLOCK_SOURCE  ROOT_CLOCK_SOURCE_BCLK
2#define BSP_SPI_CLOCK_DIV  0

  • Configure the SPI device clock source, see bsp/board/bl706_avb/clock_config.h

1#define CONFIG_GPIO19_FUNC GPIO_FUN_SPI
2#define CONFIG_GPIO20_FUNC GPIO_FUN_SPI
3#define CONFIG_GPIO21_FUNC GPIO_FUN_SPI

  • Configure SPI device multiplexing pins, see bsp/board/bl706_avb/pinmux_config.h

备注

bsp/board/bl706_avb/pinmux_config.h is currently used by all demo demos, so you need to select PINMUX_SELECT as PINMUX_LVGL, and open one of the demos

备注

In order to adapt to the bl702_avb hardware, the MOSI and MISO of SPI have been swapped by default. If you want to restore the default, modify SPI_SWAP_ENABLE in drivers/bl702_driver/hal_drv/default_config/spi_config.h to 0

 1#define BSP_USING_SPI0
 2
 3#if defined(BSP_USING_SPI0)
 4#ifndef SPI0_CONFIG
 5#define SPI0_CONFIG \
 6{   \
 7.id = 0, \
 8.clk = 36000000,\
 9.mode = SPI_MASTER_MODE, \
10.direction = SPI_MSB_BYTE0_DIRECTION_FIRST, \
11.clk_polaraity = SPI_POLARITY_LOW, \
12.clk_phase = SPI_PHASE_1EDGE, \
13.datasize = SPI_DATASIZE_8BIT, \
14.fifo_threshold = 4, \
15}
16#endif
17#endif

  • Enable BSP_USING_SPI0 and configure SPI device, see bsp/board/bl706_avb/peripheral_config.h

 1gpio_set_mode(LCD_CS_PIN,GPIO_OUTPUT_MODE);
 2gpio_set_mode(LCD_DC_PIN,GPIO_OUTPUT_MODE);
 3gpio_write(LCD_CS_PIN,1); //CS1
 4gpio_write(LCD_DC_PIN,1); //DC
 5
 6spi0 = device_find("spi0");
 7if(spi0)
 8{
 9    device_close(spi0);
10}
11else{
12    spi_register(SPI0_INDEX,"spi0",DEVICE_OFLAG_RDWR);
13    spi0 = device_find("spi0");
14}
15if(spi0)
16{
17    device_open(spi0,DEVICE_OFLAG_STREAM_TX|DEVICE_OFLAG_STREAM_RX);
18}

  • Configure the LCD_CS and LCD_DC pins as output mode and pull up

  • Call spi_register function to register SPI device, currently register SPI0

  • Then use the find function to find the handle corresponding to the device and save it in the spi0 handle

  • Finally use device_open to open the spi0 device in polling sending mode

 1void LCD_WR_Byte(uint8_t data)
 2{
 3    CS1_LOW;
 4    DC_HIGH;
 5    spi_transmit(spi0,&data,1,SPI_TRANSFER_TYPE_8BIT);
 6    CS1_HIGH;
 7}
 8
 9void LCD_WR_HalfWord(uint16_t data)
10{
11    CS1_LOW;
12    DC_HIGH;
13    spi_transmit(spi0,&data,1,SPI_TRANSFER_TYPE_16BIT);
14    CS1_HIGH;
15}
16
17void LCD_WR_Word(uint32_t data)
18{
19    CS1_LOW;
20    DC_HIGH;
21    spi_transmit(spi0,&data,1,SPI_TRANSFER_TYPE_32BIT);
22    CS1_HIGH;
23}

  • Provide interface for LCD display driver

6.1.3. Compile and Program

1 $ cd <sdk_path>/bl_mcu_sdk
2 $ make BOARD=bl706_avb APP=spi_lcd

6.1.4. Experimental Phenomena

spi display!