[STM32 : SPI, using chip select]

int main(void)

{

 char Received_From_device[500] = "";        // Maximum data from device of 500 bytes

 //char character[10] = "";

    char ETX_character;

 int i,a,lazy_timeout_counter,lazy_timeout_max,tmp,adc_value;

 char c;

  

  RCC_Configuration();

  

  GPIO_Configuration();

 

  SPI2_Configuration();   //SPI configure

  

  USART1_Configuration();

 

   GPIO_SetBits(GPIOB, GPIO_Pin_12);   //set Chip Select HIGH for SPI

  

 while(USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET); // Wait for Empty

  

    USART_SendData(USART1, 0x49); // Send 'I'

 while(USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET);

 USART_SendData(USART1, 0x42); // Send 'B'

SPI_Loop:

 Delay(1000);    //1second delay

 

 //goto Jump2Here;

 

 //Select CH0 of LTC2492

 

 GPIO_ResetBits(GPIOB, GPIO_Pin_12); // Assert -CS

 Delay_us(10); // overkill

 

// You need semicolons after the whiles otherwise they repeat the next statement

 

 while(SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_TXE) == 0); //wait for transmit buffer to be empty, should be

 

 SPI_I2S_ReceiveData(SPI2); // Clear RXNE

 SPI_I2S_SendData(SPI2, LTC_Internal_Temperature_select); //LTC_Internal_Temperature_select

 while(SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_TXE) == 0); //wait for transmit buffer to not be empty (ie data loaded in)

 SPI_I2S_SendData(SPI2, 0); // Fill for 32-bits, remaining 16-bits in holding buffer

 

 while(SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_RXNE) == 0); // wait for last bit to be sent

 SPI_I2S_ReceiveData(SPI2); // Clear RXNE, first word

 while(SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_RXNE) == 0); // wait for last bit to be sent

 SPI_I2S_ReceiveData(SPI2); // Clear RXNE, second word

 

 Delay_us(10);

 GPIO_SetBits(GPIOB, GPIO_Pin_12); // Release -CS

 

 

 Delay(1000);    //1second delay

 

 

 //await result readable via SPI and read in result via SPI   two 16bit reads over SPI

 

 GPIO_ResetBits(GPIOB, GPIO_Pin_12); // Assert -CS

 Delay_us(10); // overkill

 

 while(SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_TXE) == 0); // should be empty

 

 SPI_I2S_ReceiveData(SPI2);  // clear RXNE

 SPI_I2S_SendData(SPI2, LTC_Internal_Temperature_select); // send command word

 while(SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_TXE) == 0); //wait for transmit buffer to not be empty (ie data loaded in)

 SPI_I2S_SendData(SPI2, 0); // Fill for 32-bits, remaining 16-bits in holding buffer

 while(SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_RXNE) == 0);

 tmp = SPI_I2S_ReceiveData(SPI2);  // read word from receive buffer, high order 16-bits

 adc_value =  tmp * 65536;

 while(SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_RXNE) == 0);  // wait until receive buffer is not empty

 tmp = SPI_I2S_ReceiveData(SPI2);  // read word from receive buffer, low order 16-bits

 adc_value = adc_value + tmp;

 

 Delay_us(10);

 GPIO_SetBits(GPIOB, GPIO_Pin_12); // Release -CS

 

  

 

  

 

Jump2Here:

 //send result via RS232

 

 while(USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET);

 USART_SendData(USART1, 0x43); // Send 'C'

 while(USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET);

 USART_SendData(USART1, 0x48); // Send 'H'

 while(USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET);

 USART_SendData(USART1, 0x30); // Send '0'

 while(USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET);

 USART_SendData(USART1, 0x3A); // Send ':'

 

 // Sends as binary, not ascii

 //adc_value = 1234567890;

while(USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET);

 USART_SendData(USART1, ((adc_value >> 24) & 0xFF));

while(USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET);

 USART_SendData(USART1, ((adc_value >> 16) & 0xFF));

while(USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET);

 USART_SendData(USART1, ((adc_value >>  8) & 0xFF));

while(USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET);

 USART_SendData(USART1, ((adc_value >>  0) & 0xFF));

 

 //goto SPI_Loop;

 

 while (1);

}