SPI SPI_CPOL_High，SPI_CPHA_1Edge 模式，在Reset 后第一笔少一个CLK

zodiac-386300 提问时间：2016-10-10 15:56 /

本帖最后由 zodiac-386300 于 2016-10-11 09:53 编辑

型号：STM32F411RE
如题在8bits mode，SPI SPI_CPOL_High，SPI_CPHA_1Edge模式下，Txdata 为0,1,2,3...
如图1在reset 后 bit 1在第15个 CLK出现，理应在第16个，从wave来看是reset后第一笔数据少了一个CLK导致
如图2 不再reset 再次发送则正常
如图3 在txdata为1,1,2,3... reset 后 bit 1依然在第15个 CLK出现，第一笔data “1” 神秘消失了，图4则为不再reset 再次发送正常
其它三种CPOL，CPHA模式下 wave 没有此类异常，还求大神指点
配置代码
GPIO_InitStruct.GPIO_Pin = GPIO_Pin_15 | GPIO_Pin_14 | GPIO_Pin_13;
GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_Init(GPIOB, &GPIO_InitStruct);
GPIO_PinAFConfig(GPIOB, GPIO_PinSource13, GPIO_AF_SPI2);
GPIO_PinAFConfig(GPIOB, GPIO_PinSource14, GPIO_AF_SPI2);
GPIO_PinAFConfig(GPIOB, GPIO_PinSource15, GPIO_AF_SPI2);

GPIO_InitStruct.GPIO_Pin = GPIO_Pin_12;
GPIO_InitStruct.GPIO_Mode = GPIO_Mode_OUT;
GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_UP;
GPIO_Init(GPIOB, &GPIO_InitStruct);
GPIOB->BSRRL |= GPIO_Pin_12;

SPI_InitStruct.SPI_Direction = SPI_Direction_2Lines_FullDuplex; // set to full duplex mode, seperate MOSI and MISO lines
SPI_InitStruct.SPI_Mode = SPI_Mode_Master;    // transmit in master mode, NSS pin has to be always high
SPI_InitStruct.SPI_DataSize = SPI_DataSize_8b; // one packet of data is 16 bits wide
SPI_InitStruct.SPI_CPOL = SPI_CPOL_High;       // clock is High when idle
SPI_InitStruct.SPI_CPHA = SPI_CPHA_1Edge;    // data sampled at first edge
SPI_InitStruct.SPI_NSS = SPI_NSS_Soft | SPI_NSSInternalSoft_Set; // set the NSS management to internal and pull internal NSS high
SPI_InitStruct.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_32;
SPI_InitStruct.SPI_FirstBit = SPI_FirstBit_MSB;// data is transmitted MSB first
SPI_Init(SPI2, &SPI_InitStruct);
SPI_Cmd(SPI2, ENABLE);

另外：测试过两块 STM32F411 板子都是这样的行为，板子损坏的概率应该比较小，如果理解没错的话，可能是STM32F411 SPI Peripheral 的一个小bug

å¾2 with no reset