[N32L43X Review] 5. SPI driver LCD 1.3 ST7789

dyc1229

[N32L43X Review] 5. SPI driver LCD 1.3 ST7789 [Copy link]

 

I have been busy with work recently, which has delayed the progress of the evaluation.

When I applied for the board, I mainly wanted to test the SPI performance of N32. The M4 core with a main frequency of 108MHz was very attractive to me.

It is perfect for refreshing LCD

Unfortunately, the SPI module uses the APB2 bus, which is only half of the main frequency, and the SPI module needs to divide the APB2 bus by at least half.

That is 1/4 of the main frequency, so the fastest speed is only 27MHz. And I also need to use a USB module, the main frequency is 96MHz, that is, the highest frequency of SPI is only 24MHz, what a pity.

The most convenient solution for SPI screen flashing is ESP32. Its SPI can reach 80MHz, and it can flash a 240x240 screen very smoothly.

The following is the driver, you can directly download the attachment for details

void SPIConfig(void){
    SPI_InitType SPI_InitStructure;

    GPIO_InitType GPIO_InitStructure;
	
	RCC_EnableAPB2PeriphClk(RCC_APB2_PERIPH_SPI1, ENABLE);


    GPIO_InitStructure.Pin = SPI_LCD_SCK_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Alternate = GPIO_AF1_SPI1;
    GPIO_InitStructure.GPIO_Current = GPIO_DC_4mA;
    GPIO_InitStructure.GPIO_Pull = GPIO_No_Pull;
    GPIO_InitPeripheral(SPI_LCD_SCK_PORT, &GPIO_InitStructure);

    GPIO_InitStructure.Pin = SPI_LCD_MOSI_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Alternate = GPIO_AF0_SPI1;
    GPIO_InitStructure.GPIO_Current = GPIO_DC_4mA;
    GPIO_InitStructure.GPIO_Pull = GPIO_No_Pull;
    GPIO_InitPeripheral(SPI_LCD_MOSI_PORT, &GPIO_InitStructure);

    SPI_InitStructure.DataDirection = SPI_DIR_SINGLELINE_TX;
    SPI_InitStructure.SpiMode = SPI_MODE_MASTER;
    SPI_InitStructure.DataLen = SPI_DATA_SIZE_8BITS;
#if 0
    SPI_InitStructure.CLKPOL = SPI_CLKPOL_LOW;
    SPI_InitStructure.CLKPHA = SPI_CLKPHA_FIRST_EDGE;
	SPI_InitStructure.CLKPHA = SPI_CLKPHA_SECOND_EDGE;
#else
    SPI_InitStructure.CLKPOL = SPI_CLKPOL_HIGH;
    SPI_InitStructure.CLKPHA = SPI_CLKPHA_SECOND_EDGE;
#endif
    SPI_InitStructure.NSS = SPI_NSS_SOFT;
    SPI_InitStructure.BaudRatePres = SPI_BR_PRESCALER_2; // 48/4 = 12MHz
    SPI_InitStructure.FirstBit = SPI_FB_MSB;
    SPI_InitStructure.CRCPoly = 7;

    SPI_Init(SPI_LCD, &SPI_InitStructure);
    SPI_Enable(SPI_LCD, ENABLE);	
}

#if LCDTYPE == 0
void LCD_Writ_Bus(uint8_t dat) {
    // uint8_t shiftdat = 0;
    // shiftdat = shift_byte(dat);
    LCD_CS_CLR;
    // LCD_WR_SET;
    DATAOUT(dat);
    LCD_WR_CLR;
    // delay_us(5);
    LCD_WR_SET;
    LCD_CS_SET;
    LCD_DC_SET;
}
#elif LCDTYPE == 1
void LCD_Writ_Bus(uint8_t dat) {
    uint16_t retry = 0;
    /* Wait for SPIy Tx buffer empty */
    while (SPI_I2S_GetStatus(SPI_LCD, SPI_I2S_TE_FLAG) == RESET)
        ;
    /* Send SPIz data */
    SPI_I2S_TransmitData(SPI_LCD, dat);
}

#endif

Here you can use the previous Shell function. After powering on, the screen will refresh with a gradient color. After typing setLcd 0, you can stop the scheduled refresh task.

Type setLcd 1 to start the task.

You can also type clearLcd x to refresh the desired colors. We have already talked about how to use them before.

For people who often write interfaces, the Shell function is much more convenient. You can adjust the font size, color, and position without having to compile, burn, adjust, compile, and burn again and again.

Although there are many GUIs now, all of them have designers, but they still take up too much memory, and for low-resolution screens it feels like an overkill.

I recently found uGUI. This project is very small and has a good architecture. There are only two files in total. If you are interested, let's try it in the next issue.

By the way, there is another good thing in the routine to share with you. Vscode should be familiar to everyone. EIDE is a plug-in of Vscode, which can import MDK projects. It is very comfortable to write programs with Vscode.

EIDE is also powerful. You can write compilers directly without MDK. The main thing is that the compiler can use MDK, which can avoid a lot of unnecessary trouble. If there is a chance, this part will be taken out for a separate evaluation.

lugl4313820

How is the font library? Can I learn from it? Hehe!

秦天qintian0303

lugl4313820 posted on 2022-7-17 21:03 How is the font library? Can I learn from it? Hehe!

You can use two arrays to create a custom font library. Basically, a hundred or so fonts are enough for a project.

秦天qintian0303

If you want to refresh quickly, you still need a parallel port

xld0932

lugl4313820 posted on 2022-7-17 21:03 How is the font library? Can I learn from it? Hehe!

Look at mine, look at mine, sharing the GBK Chinese full font library, mixed display of Chinese and English

lugl4313820

xld0932 posted on 2022-7-18 09:01 Look at mine, look at mine, share the GBK Chinese full font library, Chinese and English mixed display

Okay, looking forward to it. . .