关于SPI读取MPU9250疑问请教原子大哥。

kurohard

我用SPI2读取9250,在DEBUG中，于读取9250那条语句那设置断点，单步读取数据是对的，一旦取消断点数据就不对了。程序参考了原子大哥F4开发板的SPI与http://www.openedv.com/posts/list/42044.htm这个帖子中F103对9250的配置。数据不对，不知道原子大哥能否指教一下。谢谢！

[mw_shl_code=c,true]void SPI2_Init(void) { GPIO_InitTypeDef GPIO_InitStructure; SPI_InitTypeDef SPI_InitStructure; RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE); RCC_APB1PeriphClockCmd(RCC_APB1Periph_SPI2, ENABLE); 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_Speed = GPIO_Speed_100MHz;//100MHz GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP; GPIO_Init(GPIOB, &GPIO_InitStructure); 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_InitStructure.GPIO_Pin = GPIO_Pin_12; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT; GPIO_InitStructure.GPIO_OType = GPIO_OType_PP; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;//100MHz GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP; GPIO_Init(GPIOB, &GPIO_InitStructure); RCC_APB1PeriphResetCmd(RCC_APB1Periph_SPI2,ENABLE); RCC_APB1PeriphResetCmd(RCC_APB1Periph_SPI2,DISABLE); 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(SPI2, &SPI_InitStructure); SPI_Cmd(SPI2, ENABLE); SPI2_ReadWriteByte(0xff); } [/mw_shl_code]

kurohard

PB12用作片选

klchongzi

如果是用F4的话，用片选时注意时序，MPU9250片选建立时间最少要20ns;F4的IO口操作只要5.9ns，所以要作相应延时，包括两次片选操作之间的间隔；这个问题我也被搞了还久，开始只能单次读取，不能连续，加了延时，一切都OK了