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spi_lcd_demo.rst

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SPI - TFT LCD Display

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

Software Implementation

  • See examples/spi/spi_lcd for the software code
#define BSP_SPI_CLOCK_SOURCE  ROOT_CLOCK_SOURCE_BCLK
#define BSP_SPI_CLOCK_DIV  0
  • Configure the SPI device clock source, see bsp/board/bl706_avb/clock_config.h
#define CONFIG_GPIO19_FUNC GPIO_FUN_SPI
#define CONFIG_GPIO20_FUNC GPIO_FUN_SPI
#define CONFIG_GPIO21_FUNC GPIO_FUN_SPI
  • Configure SPI device multiplexing pins, see bsp/board/bl706_avb/pinmux_config.h

Note

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

Note

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

#define BSP_USING_SPI0

#if defined(BSP_USING_SPI0)
#ifndef SPI0_CONFIG
#define SPI0_CONFIG \
{   \
.id = 0, \
.clk = 36000000,\
.mode = SPI_MASTER_MODE, \
.direction = SPI_MSB_BYTE0_DIRECTION_FIRST, \
.clk_polaraity = SPI_POLARITY_LOW, \
.clk_phase = SPI_PHASE_1EDGE, \
.datasize = SPI_DATASIZE_8BIT, \
.fifo_threshold = 4, \
}
#endif
#endif
  • Enable BSP_USING_SPI0 and configure SPI device, see bsp/board/bl706_avb/peripheral_config.h
gpio_set_mode(LCD_CS_PIN,GPIO_OUTPUT_MODE);
gpio_set_mode(LCD_DC_PIN,GPIO_OUTPUT_MODE);
gpio_write(LCD_CS_PIN,1); //CS1
gpio_write(LCD_DC_PIN,1); //DC

spi0 = device_find("spi0");
if(spi0)
{
    device_close(spi0);
}
else{
    spi_register(SPI0_INDEX,"spi0",DEVICE_OFLAG_RDWR);
    spi0 = device_find("spi0");
}
if(spi0)
{
    device_open(spi0,DEVICE_OFLAG_STREAM_TX|DEVICE_OFLAG_STREAM_RX);
}
  • 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
void LCD_WR_Byte(uint8_t data)
{
    CS1_LOW;
    DC_HIGH;
    spi_transmit(spi0,&data,1,SPI_TRANSFER_TYPE_8BIT);
    CS1_HIGH;
}

void LCD_WR_HalfWord(uint16_t data)
{
    CS1_LOW;
    DC_HIGH;
    spi_transmit(spi0,&data,1,SPI_TRANSFER_TYPE_16BIT);
    CS1_HIGH;
}

void LCD_WR_Word(uint32_t data)
{
    CS1_LOW;
    DC_HIGH;
    spi_transmit(spi0,&data,1,SPI_TRANSFER_TYPE_32BIT);
    CS1_HIGH;
}
  • Provide interface for LCD display driver

Compile and Program

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

Experimental Phenomena

spi display!