tanic 发表于 2019-8-7 10:11:08

STM32F0 SPI

如图，为啥我SPI的 3个字节写完了 SCK信号不停止呢
SPI_InitTypeDefSPI_InitStructure;
        GPIO_InitTypeDef GPIO_InitStructure;
       
        RCC_APB1PeriphClockCmd(RCC_APB1Periph_SPI2, ENABLE);
        RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOB, ENABLE);
       
        GPIO_PinAFConfig(GPIOB, GPIO_PinSource13, GPIO_AF_0);
GPIO_PinAFConfig(GPIOB, GPIO_PinSource14, GPIO_AF_0);
GPIO_PinAFConfig(GPIOB, GPIO_PinSource15, GPIO_AF_0);
        GPIO_InitStructure.GPIO_Pin = GPIO_Pin_13|GPIO_Pin_14|GPIO_Pin_15;
        GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd= GPIO_PuPd_UP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;;
        GPIO_Init(GPIOB,&GPIO_InitStructure);

       
SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex;
        SPI_InitStructure.SPI_Mode = SPI_Mode_Master;
SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b;
SPI_InitStructure.SPI_CPOL = SPI_CPOL_High;
SPI_InitStructure.SPI_CPHA = SPI_CPHA_2Edge;
SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;
SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_64;
SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_LSB;
SPI_InitStructure.SPI_CRCPolynomial = 7;
SPI_Init(SPI2, &SPI_InitStructure);        
       
        SPI_RxFIFOThresholdConfig(SPI2,SPI_RxFIFOThreshold_QF);
        SPI_Cmd(SPI2, ENABLE);
uint8_t spi2_read_write(uint16_t a)
{
        while(RESET==(SPI2->SR & SPI_I2S_FLAG_TXE));
        SPI2->DR = a;
        while(RESET==(SPI2->SR & SPI_I2S_FLAG_RXNE));
        a = SPI2->DR;
        while(RESET==(SPI2->SR & SPI_I2S_FLAG_TXE));
        while(RESET==(SPI2->SR & SPI_I2S_FLAG_RXNE));
       
        SPI_I2S_ClearFlag(SPI2,SPI_I2S_FLAG_OVR);
        return a;
}void LensWriteReg(uint8_t addr,uint16_t data)
{
        uint8_t buf;
        buf=addr&0x3f;
        buf=data;
        buf=data>>8;
        CS_1;
        spi2_read_write(buf);
        spi2_read_write(buf);
        spi2_read_write(buf);
        CS_0;
}

tanic 发表于 2019-8-7 10:14:00

用HAL傻瓜式配置，是没有问题的

tanic 发表于 2019-8-7 10:58:29

*(uint8_t*)&SPI2->DR = (uint8_t)a;
即可

butterflyspring 发表于 2019-8-7 17:22:38

对比一下两种配置后的寄存器内容呗;P

tanic 发表于 2019-8-8 09:23:28

butterflyspring 发表于 2019-8-7 17:22
对比一下两种配置后的寄存器内容呗

神奇的操作
将DR地址转换为 uint8_t* 和 uint16_t* 是两种不同的情况,
在根据初始化配置的8bit(包含以下)用uint8_t*高于8的用uint16_t*

tanic 发表于 2019-8-8 09:25:53

(中文版)手册翻遍没找到相关说明,看库试出来的:)
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