[LV6] Mikroračunalni sustavi - SPI

/*
******************************************************************************
SPI - Serial Peripheral Interface
******************************************************************************
*/

/* Includes */
#include <stddef.h>
#include "stm32f10x.h"
#include "stm32f10x_rcc.h"
#include "stm32f10x_gpio.h"
#include "stm32f10x_spi.h"

void initGPIO(void);
void initSPI(void);
void SPI_WriteRead(SPI_TypeDef *SPIx, uint8_t *txBuff, uint8_t *rxBuff, int count);

uint8_t tx_buff[10] = {1, 3, 5, 7, 9, 11, 13, 17}; //registar koji saljemo
uint8_t rx_buff[10]; //registar u koji primamo podatke

int main(void)
{
    //inicijalizacija
    initGPIO();
    initSPI();

    //ciklocko ponavljanje
    while(1){
        GPIO_WriteBit(GPIOA, GPIO_Pin_4, Bit_RESET); //palimo ledicu
        SPI_WriteRead(SPI1, tx_buff, rx_buff, 5); //saljemo prvih 5 podataka
        GPIO_WriteBit(GPIOA, GPIO_Pin_4, Bit_SET); //gasimo ledicu
    }

}

//GPIO za SPI1
void initGPIO(void) {
    GPIO_InitTypeDef GPIO_InitStruct;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);

    //MOSI PA7
    GPIO_StructInit(&GPIO_InitStruct);
    GPIO_InitStruct.GPIO_Pin = GPIO_Pin_7;
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStruct);

    //MISO PA6
    GPIO_StructInit(&GPIO_InitStruct);
    GPIO_InitStruct.GPIO_Pin = GPIO_Pin_6;
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_IPU;
    GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStruct);

    //SCLK PA5
    GPIO_StructInit(&GPIO_InitStruct);
    GPIO_InitStruct.GPIO_Pin = GPIO_Pin_5;
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_WriteBit(GPIOA, GPIO_Pin_5, Bit_RESET); //postavlja se u neaktivnu razinu (neaktivan u 0)
    GPIO_Init(GPIOA, &GPIO_InitStruct);

    //SS PA4
    GPIO_StructInit(&GPIO_InitStruct);
    GPIO_InitStruct.GPIO_Pin = GPIO_Pin_4;
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_Out_PP;
    GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_WriteBit(GPIOA, GPIO_Pin_4, Bit_SET); //postavlja se u neaktivnu razinu (neaktivan u 1)
    GPIO_Init(GPIOA, &GPIO_InitStruct);

}

//SPI1
void initSPI(void) {
    SPI_InitTypeDef SPI_InitStruct;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1, ENABLE);

    SPI_StructInit(&SPI_InitStruct);
    SPI_InitStruct.SPI_Direction = SPI_Direction_2Lines_FullDuplex;
    SPI_InitStruct.SPI_Mode = SPI_Mode_Master;
    SPI_InitStruct.SPI_DataSize = SPI_DataSize_8b; //vecina spi 8b
    SPI_InitStruct.SPI_FirstBit = SPI_FirstBit_MSB;
    SPI_InitStruct.SPI_CPHA = SPI_CPHA_1Edge; //reagira na 1. brid
    SPI_InitStruct.SPI_CPOL = SPI_CPOL_Low; //neaktivan u 0
    SPI_InitStruct.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_32; //Ukoliko je brzina uređaja s kojim komuniciramo 3MHz (72/3 = 24 => prvi veci 32)
    SPI_InitStruct.SPI_NSS = SPI_NSS_Soft; //rucno kontroliranje
    //SPI_InitStruct.SPI_CRCPolynomial => CRC ispravak pogrešaka kod prijenosa podataka

    SPI_Init(SPI1, &SPI_InitStruct);

    SPI_Cmd(SPI1, ENABLE);
}

void SPI_WriteRead(SPI_TypeDef *SPIx, uint8_t *txBuff, uint8_t *rxBuff, int count){
    SPI_I2S_SendData(SPIx, *txBuff++); //saljemo 1.

    for(int i = 0; i < count - 1; i++) { //saljemo count-1
        while(SPI_I2S_GetFlagStatus(SPIx, SPI_I2S_FLAG_TXE) == 0); //cekamo da se svi podaci uspjesno porenesu (da flag bude 1)
        SPI_I2S_SendData(SPIx, *txBuff++);

        while(SPI_I2S_GetFlagStatus(SPIx, SPI_I2S_FLAG_RXNE) == 0);
        *rxBuff++ = SPI_I2S_ReceiveData(SPIx);
    }
    while(SPI_I2S_GetFlagStatus(SPIx, SPI_I2S_FLAG_RXNE) == 0); //saljemo zadnji
    *rxBuff++ = SPI_I2S_ReceiveData(SPIx);

    while(SPI_I2S_GetFlagStatus(SPIx, SPI_I2S_FLAG_BSY) == SET); //provjera dal je sve zavrseno
}