STM32模拟SPI的程序
来源：个人图书馆-myallmy
2023-07-31 12:32:34
(资料图片仅供参考)
最近完成的一个项目因为SPI管脚被别的资源占用了，只能通过模拟SPI对存储器进行操作。最后测试发现模拟SPI的速度也很快，和硬件SPI相比感觉不到太大的差异。现将模拟SPI的程序分享如下：
管脚定义，大家可以根据需要自行修改，任何一个GPIO都可以模拟SPI
#define SPI_WP_PIN GPIO_Pin_6#define SPI_WP_PORT GPIOC#define SPI_CS_PIN GPIO_Pin_15#define SPI_CS_PORT GPIOA#define SPI_CLK_PIN GPIO_Pin_3#define SPI_CLK_PORT GPIOB#define SPI_MOSI_PIN GPIO_Pin_12#define SPI_MOSI_PORT GPIOC#define SPI_MISO_PIN GPIO_Pin_4#define SPI_MISO_PORT GPIOB#define SPI_BASE SPI3#define SPI_FLASH_CS_LOW() GPIO_ResetBits(SPI_CS_PORT, SPI_CS_PIN) /* Select SPI MEM1: ChipSelect pin low */#define SPI_FLASH_CS_HIGH() GPIO_SetBits(SPI_CS_PORT, SPI_CS_PIN) /* Deselect SPI MEM1: ChipSelect pin high */#define SPI_FLASH_WP_LOW() GPIO_ResetBits(SPI_WP_PORT, SPI_WP_PIN) //PC4#define SPI_FLASH_WP_HIGH() GPIO_SetBits(SPI_WP_PORT, SPI_WP_PIN) //PC4模拟SPI MOSI MOSI CLK
//模拟MOSIvoid SPI_MOSI(unsigned char Status){if(Status)GPIO_WriteBit(SPI_MOSI_PORT,SPI_MOSI_PIN,Bit_SET);elseGPIO_WriteBit(SPI_MOSI_PORT,SPI_MOSI_PIN,Bit_RESET);}//模拟CLKvoid SPI_CLK(unsigned char Status){if(Status)GPIO_WriteBit(SPI_CLK_PORT,SPI_CLK_PIN,Bit_SET);elseGPIO_WriteBit(SPI_CLK_PORT,SPI_CLK_PIN,Bit_RESET);}//模拟MISOunsigned char SPI_MISO(void){if(GPIO_ReadInputDataBit(SPI_MISO_PORT,SPI_MISO_PIN))return 1;else return 0;}SPI初始化
void gd25qxxInit(void){GPIO_InitTypeDef GPIO_InitStructure;GPIO_InitStructure.GPIO_Pin = SPI_MOSI_PIN; //PA5:SCK,PA7:MOSIGPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;//推挽输出GPIO_Init(SPI_MOSI_PORT, &GPIO_InitStructure);SPI_MOSI(1);GPIO_InitStructure.GPIO_Pin = SPI_CLK_PIN; //PA5:SCK,PA7:MOSIGPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;//推挽输出GPIO_Init(SPI_CLK_PORT, &GPIO_InitStructure);SPI_CLK(1);GPIO_InitStructure.GPIO_Pin = SPI_MISO_PIN ;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;GPIO_Init(SPI_MISO_PORT, &GPIO_InitStructure);GPIO_InitStructure.GPIO_Pin = SPI_CS_PIN; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;GPIO_Init(SPI_CS_PORT, &GPIO_InitStructure);SPI_FLASH_CS_HIGH();GPIO_InitStructure.GPIO_Pin = SPI_WP_PIN;GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;GPIO_Init(SPI_WP_PORT, &GPIO_InitStructure);SPI_FLASH_WP_HIGH();}SPI数据输入输出
uint8_t gd25qxxSendByte(uint8_t byte){unsigned char i,Result = 0;;for(i=0;i<8;i++){if(byte & 0x80)SPI_MOSI(1);else SPI_MOSI(0);byte <<= 1;SPI_CLK(0);SPI_CLK(1);Result <<= 1;if(SPI_MISO()) Result |= 0x01;}SPI_CLK(0);return(Result);}示例：
uint32_t gd25qxxReadID(void){ uint32_t Temp = 0, Temp0 = 0, Temp1 = 0, Temp2 = 0; /* Select the FLASH: Chip Select low */ SPI_FLASH_CS_LOW(); /* Send "RDID " instruction */ gd25qxxSendByte(0x9F); /* Read a byte from the FLASH */ Temp0 = gd25qxxSendByte(DUMMY_BYTE); /* Read a byte from the FLASH */ Temp1 = gd25qxxSendByte(DUMMY_BYTE); /* Read a byte from the FLASH */ Temp2 = gd25qxxSendByte(DUMMY_BYTE); /* Deselect the FLASH: Chip Select high */ SPI_FLASH_CS_HIGH(); Temp = (Temp0 << 16) | (Temp1 << 8) | Temp2; return Temp;}
