Микроконтроллеры

пример

/********************************** (C) COPYRIGHT *******************************
 * File Name          : main.c
 * Author             : WCH
 * Version            : V1.0.0
 * Date               : 2022/08/08
 * Description        : Main program body.
*********************************************************************************
* Copyright (c) 2021 Nanjing Qinheng Microelectronics Co., Ltd.
* Attention: This software (modified or not) and binary are used for 
* microcontroller manufactured by Nanjing Qinheng Microelectronics.
*******************************************************************************/

/*
 *@Note
 two-wire full duplex mode, master/slave mode, data transceiver:
 Master:SPI1_SCK(PC5)、SPI1_MISO(PC7)、SPI1_MOSI(PC6).
 Slave:SPI1_SCK(PC5)、SPI1_MISO(PC7)、SPI1_MOSI(PC6).

 This example demonstrates simultaneous full-duplex transmission and reception
 between Master and Slave.
 Note: The two boards download the Master and Slave programs respectively,
 and power on at the same time.
  Hardware connection:PC5 -- PC5
                      PC6 -- PC6
                      PC7 -- PC7

*/


#include "debug.h"
#include "string.h"

/* SPI Mode Definition */
#define HOST_MODE   0
#define SLAVE_MODE   1

/* SPI Communication Mode Selection */
//#define SPI_MODE   HOST_MODE
#define SPI_MODE   SLAVE_MODE

/* Global define */
#define Size 18

/* Global Variable */

u16 TxData[Size] = { 0x0101, 0x0202, 0x0303, 0x0404, 0x0505, 0x0606,
                     0x1111, 0x1212, 0x1313, 0x1414, 0x1515, 0x1616,
                     0x2121, 0x2222, 0x2323, 0x2424, 0x2525, 0x2626 };
u16 RxData[Size];

/*********************************************************************
 * @fn      SPI_FullDuplex_Init
 *
 * @brief   Configuring the SPI for full-duplex communication.
 *
 * @return  none
 */
void SPI_FullDuplex_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStructure={0};
    SPI_InitTypeDef SPI_InitStructure={0};

    RCC_APB2PeriphClockCmd( RCC_APB2Periph_GPIOC | RCC_APB2Periph_SPI1, ENABLE );

#if (SPI_MODE == HOST_MODE)
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init( GPIOC, &GPIO_InitStructure );

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_Init( GPIOC, &GPIO_InitStructure );

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init( GPIOC, &GPIO_InitStructure );

#elif (SPI_MODE == SLAVE_MODE)
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_Init( GPIOC, &GPIO_InitStructure );

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init( GPIOC, &GPIO_InitStructure );

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_Init( GPIOC, &GPIO_InitStructure );

#endif

    SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex;

#if (SPI_MODE == HOST_MODE)
    SPI_InitStructure.SPI_Mode = SPI_Mode_Master;

#elif (SPI_MODE == SLAVE_MODE)
    SPI_InitStructure.SPI_Mode = SPI_Mode_Slave;

#endif

    SPI_InitStructure.SPI_DataSize = SPI_DataSize_16b;
    SPI_InitStructure.SPI_CPOL = SPI_CPOL_Low;
    SPI_InitStructure.SPI_CPHA = SPI_CPHA_1Edge;
    SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;
    SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_256;
    SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;
    SPI_InitStructure.SPI_CRCPolynomial = 7;
    SPI_Init( SPI1, &SPI_InitStructure );

    SPI_Cmd( SPI1, ENABLE );
}

/*********************************************************************
 * @fn      main
 *
 * @brief   Main program.
 *
 * @return  none
 */
int main(void)
{
    u8 i=0;
    u8 j=0;
    u8 value;

    Delay_Init();
    USART_Printf_Init(460800);
    printf("SystemClk:%d\r\n",SystemCoreClock);

#if (SPI_MODE == SLAVE_MODE)
  printf("Slave Mode\r\n");
    Delay_Ms(1000);

#endif

    SPI_FullDuplex_Init();

#if (SPI_MODE == HOST_MODE)
  printf("Host Mode\r\n");
    Delay_Ms(2000);

#endif

    while(1)
    {
        while( ( i<18 ) || ( j<18 ))
        {
            if( i<18 )
            {
                if( SPI_I2S_GetFlagStatus( SPI1, SPI_I2S_FLAG_TXE ) != RESET )
                {
                    SPI_I2S_SendData( SPI1, TxData[i] );
                    i++;
                }
            }

            if( j<18 )
            {
                if( SPI_I2S_GetFlagStatus( SPI1, SPI_I2S_FLAG_RXNE ) != RESET )
                {
                    RxData[j] = SPI_I2S_ReceiveData( SPI1 );
                    j++;
                }
            }
        }

        value = memcmp( TxData, RxData, Size );

        if( value == 0 )
        {
            printf( "Same\r\n" );
        }
        else
        {
            printf( "Different\r\n" );
        }

        while(1);
    }
}

функция SPI_I2S_GetFlagStatus

/*********************************************************************
 * @fn      SPI_I2S_SendData
 *
 * @brief   Transmits a Data through the SPIx peripheral.
 *
 * @param   SPIx - where x can be
 *            - 1 in SPI mode.
 *          Data - Data to be transmitted.
 *
 * @return  none
 */
void SPI_I2S_SendData(SPI_TypeDef *SPIx, uint16_t Data)
{
    SPIx->DATAR = Data;
}

ну и где мы дрыгаем NSS??