Question
Problem with form of SCK clock of SPI protocol !
I have been trying to perform SPI communication and observe outgoing and incoming data through MOSI & MISO. There is a weird problem in SCK weveform
There are the codes I wrote :
#include "stm32f10x.h"
#include "stm32f10x_rcc.h"
#include "stm32f10x_gpio.h"
#include "stm32f10x_spi.h"
#define SPIx_RCC RCC_APB2Periph_SPI1
#define SPIx SPI1
#define SPI_GPIO_RCC RCC_APB2Periph_GPIOA
#define SPI_GPIO GPIOA
#define SPI_PIN_MOSI GPIO_Pin_7
#define SPI_PIN_MISO GPIO_Pin_6
#define SPI_PIN_SCK GPIO_Pin_5
#define SPI_PIN_SS GPIO_Pin_4
void SPIx_Init(void);
uint8_t SPIx_Transfer(uint8_t data);
void SPIx_EnableSlave(void);
void SPIx_DisableSlave(void);
uint8_t receivedByte;
int main()
{
// Initialization struct
SPI_InitTypeDef SPI_InitStruct;
GPIO_InitTypeDef GPIO_InitStruct;
// Step 1: Initialize SPI
RCC_APB2PeriphClockCmd(SPIx_RCC, ENABLE);
SPI_InitStruct.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_256;
SPI_InitStruct.SPI_CPHA = SPI_CPHA_1Edge;
SPI_InitStruct.SPI_CPOL = SPI_CPOL_Low;
SPI_InitStruct.SPI_DataSize = SPI_DataSize_8b;
SPI_InitStruct.SPI_Direction = SPI_Direction_2Lines_FullDuplex;
SPI_InitStruct.SPI_FirstBit = SPI_FirstBit_MSB;
SPI_InitStruct.SPI_Mode = SPI_Mode_Master;
SPI_InitStruct.SPI_NSS = SPI_NSS_Soft | SPI_NSSInternalSoft_Set;
SPI_Init(SPIx, &SPI_InitStruct);
SPI_Cmd(SPIx, ENABLE);
// Step 2: Initialize GPIO
RCC_APB2PeriphClockCmd(SPI_GPIO_RCC, ENABLE);
// GPIO pins for MOSI, MISO, and SCK
GPIO_InitStruct.GPIO_Pin = SPI_PIN_MOSI | SPI_PIN_MISO | SPI_PIN_SCK;
GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(SPI_GPIO, &GPIO_InitStruct);
// GPIO pin for SS
GPIO_InitStruct.GPIO_Pin = SPI_PIN_SS;
GPIO_InitStruct.GPIO_Mode = GPIO_Mode_Out_PP;
GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(SPI_GPIO, &GPIO_InitStruct);
// Disable SPI slave device
SPIx_DisableSlave();
receivedByte = SPIx_Transfer(0x15);
while(1)
{
}
}
uint8_t SPIx_Transfer(uint8_t data)
{
uint8_t receivedOne;
SPIx_EnableSlave();
// Write data to be transmitted to the SPI data register
SPIx->DR = data;
// Wait until transmit complete
while (!(SPIx->SR & (SPI_I2S_FLAG_TXE)));
// Wait until receive complete
while (!(SPIx->SR & (SPI_I2S_FLAG_RXNE)));
// Wait until SPI is not busy anymore
while (SPIx->SR & (SPI_I2S_FLAG_BSY));
// Return received data from SPI data register
receivedOne = SPIx->DR;
SPIx_DisableSlave();
return receivedOne;
}
void SPIx_EnableSlave()
{
// Set slave SS pin low
SPI_GPIO->BRR = SPI_PIN_SS;
}
void SPIx_DisableSlave()
{
// Set slave SS pin high
SPI_GPIO->BSRR = SPI_PIN_SS;
}What seems to be my problem ?
Thanks in Advance !