STM32F4: receiving one shot of data on the SPI bus in receive only

gistfile1.txt

#include <stm32f4xx.h>
#include "stm32f4xx_conf.h"
#include "stm32f4_discovery.h"
#include "math.h"
#include "arm_math.h"

volatile uint16_t counter = 0;

volatile uint16_t savedCounter = 0;
uint16_t parallelPins = GPIO_Pin_3 | GPIO_Pin_4 | GPIO_Pin_5 | GPIO_Pin_6 | GPIO_Pin_7 | GPIO_Pin_8 | GPIO_Pin_9 | GPIO_Pin_10;

void sendCounter();

__attribute__ ((noreturn)) void main(void) {
    //enable FPU
    SCB->CPACR |= 0b000000000111100000000000000000000UL;

    STM_EVAL_LEDInit(LED3);
    STM_EVAL_LEDInit(LED4);
    STM_EVAL_LEDInit(LED5);
    STM_EVAL_LEDInit(LED6);
    STM_EVAL_LEDOff(LED3);
    STM_EVAL_LEDOff(LED4);
    STM_EVAL_LEDOff(LED5);
    STM_EVAL_LEDOff(LED6);

    RCC_APB1PeriphClockCmd(RCC_APB1Periph_SPI2, ENABLE);
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE);
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOE, ENABLE);

    GPIO_PinAFConfig(GPIOB, GPIO_PinSource12, GPIO_AF_SPI2);
    GPIO_PinAFConfig(GPIOB, GPIO_PinSource13, GPIO_AF_SPI2);
    GPIO_PinAFConfig(GPIOB, GPIO_PinSource14, GPIO_AF_SPI2);
    GPIO_PinAFConfig(GPIOB, GPIO_PinSource15, GPIO_AF_SPI2);

    GPIO_Init(GPIOB, &(GPIO_InitTypeDef) {
            .GPIO_Pin =  GPIO_Pin_12 | GPIO_Pin_13 | GPIO_Pin_15,
            .GPIO_Mode = GPIO_Mode_AF,
            .GPIO_Speed = GPIO_Speed_100MHz,
            .GPIO_OType = GPIO_OType_PP,
            .GPIO_PuPd = GPIO_PuPd_DOWN});
    GPIO_Init(GPIOB, &(GPIO_InitTypeDef) {
            .GPIO_Pin =GPIO_Pin_14,
            .GPIO_Mode = GPIO_Mode_AF,
            .GPIO_Speed = GPIO_Speed_100MHz,
            .GPIO_OType = GPIO_OType_PP,
            .GPIO_PuPd = GPIO_PuPd_NOPULL});
    GPIO_Init(GPIOB, &(GPIO_InitTypeDef) {
            .GPIO_Pin = GPIO_Pin_11,
            .GPIO_Mode = GPIO_Mode_OUT,
            .GPIO_Speed = GPIO_Speed_100MHz,
            .GPIO_OType = GPIO_OType_PP});
    GPIO_Init(GPIOE, &(GPIO_InitTypeDef) {
            .GPIO_Pin = parallelPins,
            .GPIO_Mode = GPIO_Mode_OUT,
            .GPIO_Speed = GPIO_Speed_100MHz,
            .GPIO_OType = GPIO_OType_PP});
    SPI_I2S_DeInit(SPI2);
    SPI_Init(SPI2, &(SPI_InitTypeDef) {
            .SPI_Mode = SPI_Mode_Master,
            .SPI_Direction = SPI_Direction_2Lines_RxOnly,
            .SPI_DataSize = SPI_DataSize_8b,
            .SPI_CPOL = SPI_CPOL_Low,
            .SPI_CPHA = SPI_CPHA_1Edge,
            .SPI_NSS = SPI_NSS_Soft,
            .SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_4,
            .SPI_FirstBit = SPI_FirstBit_MSB,
            .SPI_CRCPolynomial = 7
    });

    GPIO_SetBits(GPIOB, GPIO_Pin_11);
    SPI_Cmd(SPI2, DISABLE);
    SPI_TIModeCmd(SPI2, DISABLE);
    STM_EVAL_PBInit(BUTTON_USER, BUTTON_MODE_EXTI);
    savedCounter = 5;
    counter = 5;
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wmissing-noreturn"
    while (1) {

        sendCounter();
        receiveCounter();
        for (uint32_t i = 0; i < 10000; i++)
                __asm__("");
    }
#pragma clang diagnostic pop
}

void parallelData(uint16_t data) {
    GPIO_ResetBits(GPIOE, parallelPins);
    GPIO_SetBits(GPIOE, parallelPins & (data << 3));

    for (uint32_t i = 0; i < 10000; i++)
            __asm__("");
}

int readData() {
    GPIO_ResetBits(GPIOB, GPIO_Pin_11);
    for (uint32_t i = 0; i < 10000; i++)
            __asm__("");
    GPIO_SetBits(GPIOB, GPIO_Pin_11);
    SPI_Cmd(SPI2, ENABLE);
    /*while (!SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_BSY))
            __asm__("");*/

    while (!SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_RXNE))
            __asm__("");

    SPI_Cmd(SPI2, DISABLE);
    return SPI_I2S_ReceiveData(SPI2);
}

void sendCounter() {
    parallelData(counter);
}

void receiveCounter() {
    STM_EVAL_LEDOff(LED3);
    STM_EVAL_LEDOff(LED4);
    STM_EVAL_LEDOff(LED5);
    STM_EVAL_LEDOff(LED6);
    int received = readData();
    if (received == counter) {
        STM_EVAL_LEDOn(LED3);
        STM_EVAL_LEDOn(LED4);
    }
    else {
        STM_EVAL_LEDOn(LED5);
        if (SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_OVR))
            STM_EVAL_LEDOn(LED6);
    }

}

void EXTI0_IRQHandler(void) {
    if (EXTI_GetITStatus(EXTI_Line0) != RESET) {
        counter++;

        sendCounter();
        receiveCounter();
        for (uint32_t i = 0; i < 10000; i++)
                __asm__("");
        EXTI_ClearITPendingBit(EXTI_Line0);
    }
}