Posted on March 01, 2014 at 18:26The registers aren't getting affected when I run the following code on the board. The clock is getting set however the SPI->CR1 register is not getting affected at all, upon debugging the code it shows only 0's.
&sharpinclude <stm32f2xx.h>
&sharpinclude <GPIO_STM32F2xx.h>
//&sharpinclude ''SPI_STM32F2xx.c''
void init123()
{
RCC->AHB1ENR |= (0x01); //IO port A clock enable for GPIO Pins for MOSI,MISO and SCK
GPIO_PinConfigure(GPIOA,5,GPIO_MODE_AF,GPIO_OUTPUT_PUSH_PULL,GPIO_OUTPUT_SPEED_50MHz,GPIO_NO_PULL_UP_DOWN); //For PA5
GPIO_PinConfigure(GPIOA,6,GPIO_MODE_AF,GPIO_OUTPUT_PUSH_PULL,GPIO_OUTPUT_SPEED_50MHz,GPIO_NO_PULL_UP_DOWN); //For PA6
GPIO_PinConfigure(GPIOA,7,GPIO_MODE_AF,GPIO_OUTPUT_PUSH_PULL,GPIO_OUTPUT_SPEED_50MHz,GPIO_NO_PULL_UP_DOWN); //For PA7
//For configuring the above pins in SPI
GPIO_PinAF (GPIOA,5,GPIO_AF_SPI1);
GPIO_PinAF (GPIOA,6,GPIO_AF_SPI1);
GPIO_PinAF (GPIOA,7,GPIO_AF_SPI1);
RCC->AHB1ENR |= (0x01<<3); //IO port E clock enable fr GPIO Pins for Chip Select
GPIO_PinConfigure(GPIOE,7,GPIO_MODE_OUTPUT,GPIO_OUTPUT_PUSH_PULL,GPIO_OUTPUT_SPEED_50MHz,GPIO_PULL_UP); //For Chip Select - PE7
GPIOE->BSRRL |= (0x01<<6); //For setting PE7 High
SPI1->CR1 &= ~(0x01<<6); //SPI Enable
RCC->APB2ENR |= (0x01<<11); //SPI clock enable
SPI1->CR1 &= ~(0x01<<15); //Full Duplex mode
SPI1->CR1 |= (0x01<<2); //SPI in Master Mode
SPI1->CR1 &= ~(0x01<<11); //8 bit data format
SPI1->CR1 &= ~ (0x01<<1); // CPOL - 0
SPI1->CR1 |= 0x01; // CPHA - 1
SPI1->CR1 &= ~(0x111<<3); //Baud Rate 000 config
SPI1->CR1 &= ~ (0x01<<6); // MSB First
SPI1->CR1 |= (0x01<<6); //SPI Enable
}
uint8_t send123(uint8_t data)
{
SPI1->DR=data;
while (!(SPI1->SR & 0x10)); // wait until transmit complete
while (!(SPI1->SR & 0x01)); // wait until receive complete
while (!(SPI1->SR & 0x01<<6)); // wait until SPI is not busy anymore
return SPI1->DR;
}
int main(void)
{
uint8_t received_val = 0;
init123();
while(1)
{
GPIOE->BSRRL |= (0x01<<6); //For setting PE7 Low
send123(0xAA); // transmit data
received_val = send123(0x00); // transmit dummy byte and receive data
GPIOE->BSRRL |= (0x01<<6); //For setting PE7 High
}
}
#spi #stm32f2xx #stm32f2xx #spi
