stm32 实现对6835 或6825 的spi数据读取

stm32 实现对6835 或6825 的spi数据读取
1,SPI初始化部分
本例程使用的是stm32F1系列单片机
void _Spi::SPI1_Init(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
SPI_InitTypeDef SPI_InitStructure;

RCC_APB2PeriphClockCmd(	RCC_APB2Periph_GPIOA, ENABLE );//PORTB时钟使能 
RCC_APB2PeriphClockCmd(	RCC_APB2Periph_SPI1,  ENABLE );//SPI1时钟使能 	

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5 | GPIO_Pin_6 | GPIO_Pin_7;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;  //PB13/14/15复用推挽输出 
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOA, &GPIO_InitStructure);//初始化GPIOA

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;  //PA4 cs
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOA, &GPIO_InitStructure);//初始化GPIOA
SPI1_Cs(1);

GPIO_SetBits(GPIOA,GPIO_Pin_5|GPIO_Pin_6|GPIO_Pin_7);  //PB13/14/15上拉

SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex;  //设置SPI单向或者双向的数据模式:SPI设置为双线双向全双工
SPI_InitStructure.SPI_Mode = SPI_Mode_Master;		//设置SPI工作模式:设置为主SPI
SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b;		//设置SPI的数据大小:SPI发送接收8位帧结构
SPI_InitStructure.SPI_CPOL = SPI_CPOL_High;		//串行同步时钟的空闲状态为高电平
SPI_InitStructure.SPI_CPHA = SPI_CPHA_2Edge;	//串行同步时钟的第二个跳变沿（上升或下降）数据被采样
SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;		//NSS信号由硬件（NSS管脚）还是软件（使用SSI位）管理:内部NSS信号有SSI位控制
SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_8;		//定义波特率预分频的值:波特率预分频值为256
SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;	//指定数据传输从MSB位还是LSB位开始:数据传输从MSB位开始
SPI_InitStructure.SPI_CRCPolynomial = 7;	//CRC值计算的多项式
SPI_Init(SPI1, &SPI_InitStructure);  //根据SPI_InitStruct中指定的参数初始化外设SPIx寄存器

SPI_Cmd(SPI1, ENABLE); //使能SPI外设

// SPI1_ReadWriteByte(0xff);//启动传输

}

2.数据读取
CS引脚使用的是软件的 ,可以根据需要自己修改
void Foc::EncoderRead()
{
uint8_t txdata[6] = {0x83,0x00,0x00,0x00};
uint8_t readByte=4;
if(encoderType35)
{
readByte=6;
txdata[0]=0xa0;
txdata[1]=0x03;
}
uint8_t rxdata[6] = {0},check1 = 0,check2 = 0;
uint32_t rxvalue = 0,i;
Cspi1.SPI1_Cs(0);
delay_us(2);
for(i=0;i<readByte;i++)
{
rxdata[i]=Cspi1.SPI1_ReadWriteByte(txdata[i]);
}
delay_us(2);
Cspi1.SPI1_Cs(1);
if(encoderType16)//6816
{
rxvalue |= rxdata[1]<<8;
rxvalue |= rxdata[2];
rxvalue >>=2;
for(i = 0;i < 14;i ++)
{
check1 += (rxvalue >> (i)) & 0x1;
}

	if((check1 & 0x1) == (rxdata[2] & 0x1))
	{
		EncoderNum= rxvalue; //数据正常
		EncoderNum=(EncoderBitWith-EncoderNum)&EncoderBitWith;
		CurrentAngle=(EncoderNum-EncoderOrg)&EncoderBitWith;
	}
}
else if(encoderType==35)//6835
{
		rxvalue |= rxdata[2];
		rxvalue <<= 8;
		rxvalue |= rxdata[3] ;
		rxvalue <<= 8;
		rxvalue |= rxdata[4] ;
		check1=rxdata[5];
		check2=cal_crc_table(&rxdata[2], 3) ;
		if(check1 == check2 )
		{
			EncoderNum= rxvalue>>3; //数据正常
			CurrentAngle=(EncoderNum-EncoderOrg)&EncoderBitWith;
		}
else if(encoderType==25)//6825
		{
			rxvalue |= rxdata[1];
			rxvalue <<= 6;
			rxvalue |= rxdata[2] >> 2;
			rxvalue <<= 4;
			rxvalue |= rxdata[3] >> 4;
			for(i = 0;i < 14;i ++)
			{
				check1 += (rxvalue >> (4 + i)) & 0x1;
			}
			for(i = 0;i < 4;i ++)
			{
				check2 += (rxvalue >> i) & 0x1;
			}
			if(((check1 & 0x1) == (rxdata[2] & 0x1)) && ((check2 & 0x1) == (rxdata[3] >> 2 & 0x1)))
			{
    			EncoderNum= rxvalue; //数据正常
				CurrentAngle=(EncoderNum-EncoderOrg)&EncoderBitWith;
			}
	}
}

}
3,CRC昨天忘记放了,今天补上
static const unsigned char crc_table[] =
{
0x00,0x07,0x0e,0x09,0x1c,0x1b,0x12,0x15,0x38,0x3f,0x36,0x31,0x24,0x23,0x2a,0x2d,
0x70,0x77,0x7e,0x79,0x6c,0x6b,0x62,0x65,0x48,0x4f,0x46,0x41,0x54,0x53,0x5a,0x5d,
0xe0,0xe7,0xee,0xe9,0xfc,0xfb,0xf2,0xf5,0xd8,0xdf,0xd6,0xd1,0xc4,0xc3,0xca,0xcd,
0x90,0x97,0x9e,0x99,0x8c,0x8b,0x82,0x85,0xa8,0xaf,0xa6,0xa1,0xb4,0xb3,0xba,0xbd,
0xc7,0xc0,0xc9,0xce,0xdb,0xdc,0xd5,0xd2,0xff,0xf8,0xf1,0xf6,0xe3,0xe4,0xed,0xea,
0xb7,0xb0,0xb9,0xbe,0xab,0xac,0xa5,0xa2,0x8f,0x88,0x81,0x86,0x93,0x94,0x9d,0x9a,
0x27,0x20,0x29,0x2e,0x3b,0x3c,0x35,0x32,0x1f,0x18,0x11,0x16,0x03,0x04,0x0d,0x0a,
0x57,0x50,0x59,0x5e,0x4b,0x4c,0x45,0x42,0x6f,0x68,0x61,0x66,0x73,0x74,0x7d,0x7a,
0x89,0x8e,0x87,0x80,0x95,0x92,0x9b,0x9c,0xb1,0xb6,0xbf,0xb8,0xad,0xaa,0xa3,0xa4,
0xf9,0xfe,0xf7,0xf0,0xe5,0xe2,0xeb,0xec,0xc1,0xc6,0xcf,0xc8,0xdd,0xda,0xd3,0xd4,
0x69,0x6e,0x67,0x60,0x75,0x72,0x7b,0x7c,0x51,0x56,0x5f,0x58,0x4d,0x4a,0x43,0x44,
0x19,0x1e,0x17,0x10,0x05,0x02,0x0b,0x0c,0x21,0x26,0x2f,0x28,0x3d,0x3a,0x33,0x34,
0x4e,0x49,0x40,0x47,0x52,0x55,0x5c,0x5b,0x76,0x71,0x78,0x7f,0x6a,0x6d,0x64,0x63,
0x3e,0x39,0x30,0x37,0x22,0x25,0x2c,0x2b,0x06,0x01,0x08,0x0f,0x1a,0x1d,0x14,0x13,
0xae,0xa9,0xa0,0xa7,0xb2,0xb5,0xbc,0xbb,0x96,0x91,0x98,0x9f,0x8a,0x8d,0x84,0x83,
0xde,0xd9,0xd0,0xd7,0xc2,0xc5,0xcc,0xcb,0xe6,0xe1,0xe8,0xef,0xfa,0xfd,0xf4,0xf3
};
unsigned char cal_crc_table(unsigned char *ptr, unsigned char len)
{
uint8_t crc=0x00; //计算的初始crc值，也存放结果
while(len–)
{
crc ^= *ptr++; //每次先与需要计算的数据异或,计算完指向下一数据
crc = crc_table[crc];
}
return (crc);

}

作者：airei0