AS5048A讲解

编码器角度读取流程：
一、初始化SPI。
注意这里需要初始化SPI读写位16位，平时的例程，正点原子，或者野火均是8位，需要修改下位数

void SPI1_Init(void)
{	 GPIO_InitTypeDef  GPIO_InitStructure;SPI_InitTypeDef  SPI_InitStructure;RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);//Ê¹ÄÜGPIOBÊ±ÖÓRCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1, ENABLE);//Ê¹ÄÜSPI1Ê±ÖÓ//GPIOFB3,4,5³õÊ¼»¯ÉèÖÃGPIO_InitStructure.GPIO_Pin = GPIO_Pin_5|GPIO_Pin_6|GPIO_Pin_7;//PB3~5¸´ÓÃ¹¦ÄÜÊä³ö	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;//¸´ÓÃ¹¦ÄÜGPIO_InitStructure.GPIO_OType = GPIO_OType_PP;//ÍÆÍìÊä³öGPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;//100MHzGPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;//ÉÏÀGPIO_Init(GPIOA, &GPIO_InitStructure);//³õÊ¼»¯GPIO_PinAFConfig(GPIOA,GPIO_PinSource5,GPIO_AF_SPI1); //PB3¸´ÓÃÎª SPI1GPIO_PinAFConfig(GPIOA,GPIO_PinSource6,GPIO_AF_SPI1); //PB4¸´ÓÃÎª SPI1GPIO_PinAFConfig(GPIOA,GPIO_PinSource7,GPIO_AF_SPI1); //PB5¸´ÓÃÎª SPI1//ÕâÀïÖ»Õë¶ÔSPI¿Ú³õÊ¼»¯RCC_APB2PeriphResetCmd(RCC_APB2Periph_SPI1,ENABLE);//¸´Î»SPI1RCC_APB2PeriphResetCmd(RCC_APB2Periph_SPI1,DISABLE);//Í£Ö¹¸´Î»SPI1SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex;  //ÉèÖÃSPIµ¥Ïò»òÕßË«ÏòµÄÊý¾ÝÄ£Ê½:SPIÉèÖÃÎªË«ÏßË«ÏòÈ«Ë«¹¤SPI_InitStructure.SPI_Mode = SPI_Mode_Master;		//ÉèÖÃSPI¹¤×÷Ä£Ê½:ÉèÖÃÎªÖ÷SPISPI_InitStructure.SPI_DataSize = SPI_DataSize_16b;		//ÉèÖÃSPIµÄÊý¾Ý´óÐ¡:SPI·¢ËÍ½ÓÊÕ8Î»Ö¡½á¹¹SPI_InitStructure.SPI_CPOL = SPI_CPOL_Low;		//´®ÐÐÍ¬²½Ê±ÖÓµÄ¿ÕÏÐ×´Ì¬Îª¸ßµçÆ½SPI_InitStructure.SPI_CPHA = SPI_CPHA_2Edge;	//´®ÐÐÍ¬²½Ê±ÖÓµÄµÚ¶þ¸öÌø±äÑØ£¨ÉÏÉý»òÏÂ½µ£©Êý¾Ý±»²ÉÑùSPI_InitStructure.SPI_NSS = SPI_NSS_Soft;		//NSSÐÅºÅÓÉÓ²¼þ£¨NSS¹Ü½Å£©»¹ÊÇÈí¼þ£¨Ê¹ÓÃSSIÎ»£©¹ÜÀí:ÄÚ²¿NSSÐÅºÅÓÐSSIÎ»¿ØÖÆSPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_8;		//¶¨Òå²¨ÌØÂÊÔ¤·ÖÆµµÄÖµ:²¨ÌØÂÊÔ¤·ÖÆµÖµÎª256SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;	//Ö¸¶¨Êý¾Ý´«Êä´ÓMSBÎ»»¹ÊÇLSBÎ»¿ªÊ¼:Êý¾Ý´«Êä´ÓMSBÎ»¿ªÊ¼SPI_InitStructure.SPI_CRCPolynomial = 15;	//CRCÖµ¼ÆËãµÄ¶àÏîÊ½SPI_Init(SPI1, &SPI_InitStructure);  //¸ù¾ÝSPI_InitStructÖÐÖ¸¶¨µÄ²ÎÊý³õÊ¼»¯ÍâÉèSPIx¼Ä´æÆ÷SPI_Cmd(SPI1, ENABLE); //Ê¹ÄÜSPIÍâÉèSPI1_ReadWriteByte(0xffff);//Æô¶¯´«Êä		 
}   
//SPI1ËÙ¶ÈÉèÖÃº¯Êý
//SPIËÙ¶È=fAPB2/·ÖÆµÏµÊý
//@ref SPI_BaudRate_Prescaler:SPI_BaudRatePrescaler_2~SPI_BaudRatePrescaler_256  
//fAPB2Ê±ÖÓÒ»°ãÎª84Mhz£º
void SPI1_SetSpeed(u8 SPI_BaudRatePrescaler)
{assert_param(IS_SPI_BAUDRATE_PRESCALER(SPI_BaudRatePrescaler));//ÅÐ¶ÏÓÐÐ§ÐÔSPI1->CR1&=0XFFC7;//Î»3-5ÇåÁã£¬ÓÃÀ´ÉèÖÃ²¨ÌØÂÊSPI1->CR1|=SPI_BaudRatePrescaler;	//ÉèÖÃSPI1ËÙ¶È SPI_Cmd(SPI1,ENABLE); //Ê¹ÄÜSPI1
} 
//SPI1 ¶ÁÐ´Ò»¸ö×Ö½Ú
//TxData:ÒªÐ´ÈëµÄ×Ö½Ú
//·µ»ØÖµ:¶ÁÈ¡µ½µÄ×Ö½Ú
u16 SPI1_ReadWriteByte(u16 TxData)
{		 			 while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) == RESET){}//µÈ´ý·¢ËÍÇø¿Õ  SPI_I2S_SendData(SPI1, TxData); //Í¨¹ýÍâÉèSPIx·¢ËÍÒ»¸öbyte  Êý¾Ýwhile (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE) == RESET){} //µÈ´ý½ÓÊÕÍêÒ»¸öbyte  return SPI_I2S_ReceiveData(SPI1); //·µ»ØÍ¨¹ýSPIx×î½ü½ÓÊÕµÄÊý¾Ý	}

这是SPI的初始化

u16 SPI_AS5048A_Read(u16 TxData)
{u16 data;GPIO_ResetBits(GPIOA,GPIO_Pin_4);SPI1_ReadWriteByte(TxData);GPIO_SetBits(GPIOA,GPIO_Pin_4);CPU_TS_Tmr_Delay_US(10);GPIO_ResetBits(GPIOA,GPIO_Pin_4);data = SPI1_ReadWriteByte(0xc000);GPIO_SetBits(GPIOA,GPIO_Pin_4);data = data & 0x3fff;return data;
}

这是读写，直接调用SPI_AS5048A_Read（0xffff）就是读出来角度数据，根据寄存器应该是从0x3fff这个地址读取，这个地址进行校验等处理后就变成了0xffff，当然，这个函数是读写函数，也可以简化一点，因为我们需要从AS5048获取数据，所以从ANGLE寄存器读取数据就可以了所以可以写成这样：

u16 SPI_AS5048A_Read(void)
{u16 data;GPIO_ResetBits(GPIOA,GPIO_Pin_4);data = SPI1_ReadWriteByte(0xffff);GPIO_SetBits(GPIOA,GPIO_Pin_4);data = data & 0x3fff;return data;
}as5600_adc = SPI_AS5048A_Read();			angle = (float)(as5600_adc) / (float)16384 * 360.0f;