[Atria Development Board AT32F421 Review] SPI Usage

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[Atria Development Board AT32F421 Review] SPI Usage [Copy link]

 

There is one thing you need to pay special attention to when using domestic substitution. Look at the block diagram below. The APB1 and APB2 of this device can run at full frequency, while the APB1 of S*M is divided by 2. Sometimes after transplanting, you find that it worked before, but now it doesn’t work. You will wonder what you missed. Sometimes checking the frequency of APB1 will bring unexpected gains.

Here we see that SPI2 is connected to APB1, so, needless to say, find system_at32f4xx.c under CMSIS, where we can see its clock configuration. In addition, many clock configurations have been written in system_at32f4xx.c, just define whichever you need.

Next, we can start writing the SPI initialization function, which I have written in at32_board.c.

void SPI2_Init()
{
  GPIO_InitType GPIO_InitStructure;
  SPI_InitType  SPI_InitStructure;
	
	/* 启用时钟 */
  RCC_APB1PeriphClockCmd(RCC_APB1PERIPH_SPI2, ENABLE);
  RCC_AHBPeriphClockCmd(RCC_AHBPERIPH_GPIOB , ENABLE);
	

  /* 配置 SPI2引脚: 
	 *	SPI2_CLK-->PB13
	 *	SPI2_MOSI-->PB15
	 *	SPI2_NSS-->PB12
	 *	LCD_RS-->PB14
	 *	LCD_DC-->PB11
	 */
  GPIO_StructInit(&GPIO_InitStructure);
  GPIO_InitStructure.GPIO_Pins = GPIO_Pins_13| GPIO_Pins_15;
  GPIO_InitStructure.GPIO_MaxSpeed = GPIO_MaxSpeed_50MHz;
  GPIO_InitStructure.GPIO_OutType = GPIO_OutType_PP; 
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_Pull = GPIO_Pull_NOPULL;
  GPIO_Init(GPIOB, &GPIO_InitStructure);
	
  GPIO_InitStructure.GPIO_Pins = GPIO_Pins_11|GPIO_Pins_12|GPIO_Pins_14;
  GPIO_InitStructure.GPIO_MaxSpeed = GPIO_MaxSpeed_50MHz;
  GPIO_InitStructure.GPIO_OutType = GPIO_OutType_PP; 
  GPIO_InitStructure.GPIO_Pull = GPIO_Pull_NOPULL;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;
  GPIO_Init(GPIOB, &GPIO_InitStructure);
	
  GPIO_PinAFConfig(GPIOB, GPIO_PinsSource13, GPIO_AF_0);
  GPIO_PinAFConfig(GPIOB, GPIO_PinsSource15, GPIO_AF_0);

  /* SPI2配置*/
  SPI_DefaultInitParaConfig(&SPI_InitStructure);
  SPI_InitStructure.SPI_TransMode = SPI_TRANSMODE_TX_HALFDUPLEX   ;
  SPI_InitStructure.SPI_Mode = SPI_MODE_MASTER;
  SPI_InitStructure.SPI_FrameSize = SPI_FRAMESIZE_8BIT;
  SPI_InitStructure.SPI_CPOL = SPI_CPOL_LOW;
  SPI_InitStructure.SPI_CPHA = SPI_CPHA_1EDGE;
  SPI_InitStructure.SPI_NSSSEL = SPI_NSSSEL_SOFT;
  SPI_InitStructure.SPI_MCLKP = SPI_MCLKP_2;
  SPI_InitStructure.SPI_FirstBit = SPI_FIRSTBIT_MSB;
  SPI_InitStructure.SPI_CPOLY = 7;
  SPI_Init(SPI2, &SPI_InitStructure);
	
	SPI_Enable(SPI2, ENABLE);
}

The writing style is familiar to you. There is one more thing to note. Although it looks the same, the actual capitalization and the presence or absence of the suffix are different. Before configuring the members, the GPIO_StructInit(); and SPI_DefaultInitParaConfig(); functions are called to fill in the default values. Sometimes we may not configure every member, so it is a good habit to restore the defaults before configuring. The next step is to add the peripheral driver code to the project.

.c and .h have been added to the project. Next, we need to rewrite the header file in oled.h and modify the IO to be used.

This is basically completed. If there is no error in the compilation, you can write main. Here I took the following template myself

unsigned char COAlarm16[10][16]={


{0x00,0xC2,0xBA,0x82,0x82,0xFE,0xA2,0x90,0xFC,0x4B,0x48,0xF9,0x4A,0x48,0x08,0x00},
{0x20,0x10,0x08,0x46,0x81,0x7F,0x00,0x00,0xFF,0x22,0x22,0x3F,0x22,0x22,0x20,0x00},/*"雅",0*/
/* (16 X 16 , 宋体 )*/

{0x40,0x3C,0x10,0xFF,0x10,0x10,0x40,0x48,0x48,0x48,0x7F,0x48,0xC8,0x48,0x40,0x00},
{0x02,0x06,0x02,0xFF,0x01,0x01,0x00,0x02,0x0A,0x12,0x42,0x82,0x7F,0x02,0x02,0x00},/*"特",1*/
/* (16 X 16 , 宋体 )*/

{0x00,0x10,0x10,0x10,0x10,0x10,0xFF,0x10,0x10,0x10,0x10,0x10,0xF0,0x00,0x00,0x00},
{0x00,0x80,0x40,0x20,0x18,0x06,0x01,0x00,0x20,0x40,0x80,0x40,0x3F,0x00,0x00,0x00},/*"力",2*/
/* (16 X 16 , 宋体 )*/

{0x24,0x24,0xA4,0xFE,0xA3,0x22,0x00,0x22,0xCC,0x00,0x00,0xFF,0x00,0x00,0x00,0x00},
{0x08,0x06,0x01,0xFF,0x00,0x01,0x04,0x04,0x04,0x04,0x04,0xFF,0x02,0x02,0x02,0x00},/*"科",3*/
/* (16 X 16 , 宋体 )*/

{0x10,0x10,0x10,0xFF,0x10,0x90,0x08,0x88,0x88,0x88,0xFF,0x88,0x88,0x88,0x08,0x00},
{0x04,0x44,0x82,0x7F,0x01,0x80,0x80,0x40,0x43,0x2C,0x10,0x28,0x46,0x81,0x80,0x00},/*"技",4*/
/* (16 X 16 , 宋体 )*/

};

Finally, add main

int main(void)
{     


  while (1)
  {
    OLED_ShowString(30,0,(uint8_t*)"Arterytek",16);
		
		OLED_ShowChinese(11,26,0,16);//雅
		OLED_ShowChinese(33,26,1,16);//特
		OLED_ShowChinese(55,26,2,16);//力
		OLED_ShowChinese(77,26,3,16);//科
		OLED_ShowChinese(99,26,4,16);//技

		OLED_ShowNum(12,50,86,2,12);//电话
		OLED_ShowChar(26,50,'-',12);
		OLED_ShowNum(36,50,23,2,12);
		OLED_ShowChar(50,50,'-',12);
		OLED_ShowNum(60,50,6868,4,12);
		OLED_ShowNum(92,50,8899,4,12);
		OLED_Refresh();
		return 0;
		
		
  }
}

Also put SPI2_Init and OLED_Init in rt_hw_board_init, so that they will be initialized when the system starts.

Burn it,

This indicates that SPI is working normally.

Jacktang

When writing the SPI initialization function, I wrote it in at32_board.c. Is there any introduction in this manual?

freebsder

Thanks for sharing, looking forward to the follow-up!

eew_Violet

Jacktang posted on 2021-4-19 09:50 When writing the SPI initialization function, it was written in at32_board.c. Is there any introduction in this manual?

The spi initialization function can be written anywhere, as long as it is called in rt_board_init.

火辣西米秀

The clock configuration looks quite simple, the host is awesome