490353119 发表于 2014-8-21 10:33

stm32 使用SPI读取AD5422

STM32 使用IO模拟读取AD5422完全没问题，但是使用SPI读取不行：
SPI_I2S_DeInit(SPI_Master1);
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_Low;
SPI_InitStructure.SPI_CPHA = SPI_CPHA_1Edge;
SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;
SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_256;
SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;
SPI_InitStructure.SPI_CRCPolynomial = 7;
SPI_Init(SPI_Master1, &SPI_InitStructure);

u8 SPI_Master_RW(u8 date)
{
u8 retry=0;
while(SPI_I2S_GetFlagStatus(SPI_Master1,SPI_I2S_FLAG_TXE)==RESET)
{
retry++;
if(retry>200)
return 0;
}

SPI_I2S_SendData(SPI_Master1,date);
while(SPI_I2S_GetFlagStatus(SPI_Master1,SPI_I2S_FLAG_RXNE)==RESET)
{
retry++;
if(retry>200)
return 0;
}
return SPI_I2S_ReceiveData(SPI_Master1);
}
void AD5422_Read(u8 num,u8 *pbuf)
{
u8 i=0;
Select_DAC1();
for(i=num;i>0;i--)
{
*(pbuf+i-1)=SPI_Master_RW(AD5422_NOP);
}
NotSelect_DAC1();
}

void AD5422_Write(u8 num,u8 *pbuf)
{
u8 i=0;
Select_DAC1();
for(i=num;i>0;i--)
{
SPI_Master_RW(*(pbuf+i-1));
}
NotSelect_DAC1();
}

SPI四种模式都试过了，示波器有波形输出（CLK，CS，MOSI波形都有)，但是AD5422完全没反应。也不能读取数据。这是为什么？难道只能IO模拟不能使用STM32的SPI？

zhaojun_xf 发表于 2014-8-21 10:56

注意SPI模式，一共有4种，看看你的芯片支持哪一种。

Study_Stellaris 发表于 2014-8-21 11:00

不能只配置 SPI 外设这部分的参数，在这之前要配置 SPI 所用的4个管脚的 GPIO 的工作模式。

490353119 发表于 2014-8-21 14:06

AD5422时序图 ：使用
SPI_InitStructure.SPI_CPOL = SPI_CPOL_Low;
SPI_InitStructure.SPI_CPHA = SPI_CPHA_1Edge;
void SPI_Master_Config(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
//DMA_InitTypeDef DMA_InitStructure;
SPI_InitTypeDefSPI_InitStructure;
/* Peripheral Clock Enable -------------------------------------------------*/
/* Enable the SPI clock */
SPI_Master1_CLK_INIT(SPI_Master1_CLK, ENABLE);

/* Enable GPIO clocks */
RCC_AHB1PeriphClockCmd(SPI_Master1_SCK_GPIO_CLK | SPI_Master1_MISO_GPIO_CLK | SPI_Master1_MOSI_GPIO_CLK, ENABLE);

///* Enable DMA clock */
//RCC_AHB1PeriphClockCmd(SPI_Master1_DMA_CLK, ENABLE);

/* SPI GPIO Configuration --------------------------------------------------*/
/* GPIO Deinitialisation */
GPIO_DeInit(SPI_Master1_SCK_GPIO_PORT);
GPIO_DeInit(SPI_Master1_MISO_GPIO_PORT);
GPIO_DeInit(SPI_Master1_MOSI_GPIO_PORT);

/* Connect SPI pins to AF5 */
GPIO_PinAFConfig(SPI_Master1_SCK_GPIO_PORT, SPI_Master1_SCK_SOURCE, SPI_Master1_SCK_AF);
GPIO_PinAFConfig(SPI_Master1_MISO_GPIO_PORT, SPI_Master1_MISO_SOURCE, SPI_Master1_MISO_AF);   
GPIO_PinAFConfig(SPI_Master1_MOSI_GPIO_PORT, SPI_Master1_MOSI_SOURCE, SPI_Master1_MOSI_AF);

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd= GPIO_PuPd_NOPULL;

/* SPI SCK pin configuration */
GPIO_InitStructure.GPIO_Pin = SPI_Master1_SCK_PIN;
GPIO_Init(SPI_Master1_SCK_GPIO_PORT, &GPIO_InitStructure);

/* SPIMISO pin configuration */
GPIO_InitStructure.GPIO_Pin =SPI_Master1_MISO_PIN;
GPIO_Init(SPI_Master1_MISO_GPIO_PORT, &GPIO_InitStructure);

/* SPIMOSI pin configuration */
GPIO_InitStructure.GPIO_Pin =SPI_Master1_MOSI_PIN;
GPIO_Init(SPI_Master1_MOSI_GPIO_PORT, &GPIO_InitStructure);

/* SPI configuration -------------------------------------------------------*/
SPI_I2S_DeInit(SPI_Master1);
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_Low;
SPI_InitStructure.SPI_CPHA = SPI_CPHA_1Edge;
SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;
SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_256;
SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;
SPI_InitStructure.SPI_CRCPolynomial = 7;
SPI_Init(SPI_Master1, &SPI_InitStructure);

SPI_Cmd(SPI_Master1, ENABLE);

}

N-yoak 发表于 2019-6-13 17:33

<p>麻烦问一下， 读取寄存器的值正确，&nbsp; 但是无电压输出什么原因啊</p>
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