11. SPI 1) 输入与输出配置要求(STM32 不需要如此要求) 解决方法 : GD32 在使用SPI 时,IO 的配置必须严格遵守主从模式下的输入与输出配置,而STM32 无此要求,相关代码如下:主机模式下IO 配置(主机以SPI 为例): GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5|GPIO_Pin_7; GPIO_Init(GPIOA,&GPIO_InitStructure); GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING; GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6; GPIO_Init(GPIOA,&GPIO_InitStructure); 从机模式下IO 配置(从机以SPI2 为例): GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; GPIO_InitStructure.GPIO_Pin = GPIO_Pin_13|GPIO_Pin_15; GPIO_Init(GPIOB,&GPIO_InitStructure); GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; GPIO_InitStructure.GPIO_Pin = GPIO_Pin_14; GPIO_Init(GPIOB,&GPIO_InitStructure); 3) 在GD32 的SPI 的时钟信号,空闲状态需要配置成高电平,以保证数据的稳定性,具体代码如下 解决方法 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_256; SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB; SPI_InitStructure.SPI_CRCPolynomial = 7; SPI_Init(SPI1, &SPI_InitStructure); 4) 当作为从机时,在GD32 中,时钟信号必须为8 的整数倍。 解决方法 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_256; SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB; SPI_InitStructure.SPI_CRCPolynomial = 7; SPI_Init(SPI1, &SPI_InitStructure); 5) 在GD32 中,不能使用SPI_I2S_FLAG_BSY 该位来判断SPI 总线数据是否接收或发送完成。
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