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How to store aRxBuffer into a variable using SPI?

Question asked by Duy Khang Banh on Dec 24, 2017
Latest reply on Jan 2, 2018 by T J

Dear community,

 

I am new into the STM32 world. I have experience in arduino and would like to go deeper into the industrial world. I created a ledrider code for the STM32f103c8t6 with 74HC595 shift registers, which gave me a good introduction into the stm32 world. However, I am planning to modify an option print which contains two 74HC165 parallel to serial IC with relays directly connected to output pins of the MCU. 

 

I have setup in a breadbord version with only one 74hc165 to test the program out. Here is my main code:

 

/**
******************************************************************************
* File Name : main.c
* Description : Main program body
******************************************************************************
** This notice applies to any and all portions of this file
* that are not between comment pairs USER CODE BEGIN and
* USER CODE END. Other portions of this file, whether
* inserted by the user or by software development tools
* are owned by their respective copyright owners.
*
* COPYRIGHT(c) 2017 STMicroelectronics
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. Neither the name of STMicroelectronics nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
******************************************************************************
*/

/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "stm32f1xx_hal.h"

/* USER CODE BEGIN Includes */

/* USER CODE END Includes */

/* Private variables ---------------------------------------------------------*/
SPI_HandleTypeDef hspi1;

/* USER CODE BEGIN PV */
/* Private variables ---------------------------------------------------------*/
#define cs_set() HAL_GPIO_WritePin(GPIOA, GPIO_PIN_4, GPIO_PIN_RESET); //CS_Set(RESET)
#define cs_reset() HAL_GPIO_WritePin(GPIOA, GPIO_PIN_4, GPIO_PIN_SET); //CS_Set(RESET)
#define cs_strob() cs_reset();cs_set()
uint8_t aRxBuffer[1]={0};
/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_SPI1_Init(void);

/* USER CODE BEGIN PFP */
/* Private function prototypes -----------------------------------------------*/

/* USER CODE END PFP */

/* USER CODE BEGIN 0 */

/* USER CODE END 0 */

int main(void)
{

/* USER CODE BEGIN 1 */
/* USER CODE END 1 */

/* MCU Configuration----------------------------------------------------------*/

/* Reset of all peripherals, Initializes the Flash interface and the Systick. */
HAL_Init();

/* USER CODE BEGIN Init */

/* USER CODE END Init */

/* Configure the system clock */
SystemClock_Config();

/* USER CODE BEGIN SysInit */

/* USER CODE END SysInit */

/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_SPI1_Init();

/* USER CODE BEGIN 2 */
HAL_GPIO_WritePin(GPIOA, GPIO_PIN_4, GPIO_PIN_RESET);
HAL_GPIO_WritePin(GPIOA, GPIO_PIN_4, GPIO_PIN_SET);
HAL_SPI_Receive (&hspi1,(uint8_t *)&aRxBuffer,1 , 5000);

/* USER CODE END 2 */

/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
/* USER CODE END WHILE */
if(aRxBuffer[0]==0x00)
{
HAL_GPIO_WritePin(GPIOC, GPIO_PIN_13, GPIO_PIN_SET);

}

/* USER CODE BEGIN 3 */


/* USER CODE END 3 */

}
}
/** System Clock Configuration
*/
void SystemClock_Config(void)
{

RCC_OscInitTypeDef RCC_OscInitStruct;
RCC_ClkInitTypeDef RCC_ClkInitStruct;

/**Initializes the CPU, AHB and APB busses clocks
*/
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
RCC_OscInitStruct.HSEState = RCC_HSE_ON;
RCC_OscInitStruct.HSEPredivValue = RCC_HSE_PREDIV_DIV1;
RCC_OscInitStruct.HSIState = RCC_HSI_ON;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL9;
if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
{
_Error_Handler(__FILE__, __LINE__);
}

/**Initializes the CPU, AHB and APB busses clocks
*/
RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;
RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
{
_Error_Handler(__FILE__, __LINE__);
}

/**Configure the Systick interrupt time
*/
HAL_SYSTICK_Config(HAL_RCC_GetHCLKFreq()/1000);

/**Configure the Systick
*/
HAL_SYSTICK_CLKSourceConfig(SYSTICK_CLKSOURCE_HCLK);

/* SysTick_IRQn interrupt configuration */
HAL_NVIC_SetPriority(SysTick_IRQn, 0, 0);
}

/* SPI1 init function */
static void MX_SPI1_Init(void)
{

/* SPI1 parameter configuration*/
hspi1.Instance = SPI1;
hspi1.Init.Mode = SPI_MODE_MASTER;
hspi1.Init.Direction = SPI_DIRECTION_2LINES;
hspi1.Init.DataSize = SPI_DATASIZE_8BIT;
hspi1.Init.CLKPolarity = SPI_POLARITY_LOW;
hspi1.Init.CLKPhase = SPI_PHASE_1EDGE;
hspi1.Init.NSS = SPI_NSS_SOFT;
hspi1.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_4;
hspi1.Init.FirstBit = SPI_FIRSTBIT_MSB;
hspi1.Init.TIMode = SPI_TIMODE_DISABLE;
hspi1.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;
hspi1.Init.CRCPolynomial = 10;
if (HAL_SPI_Init(&hspi1) != HAL_OK)
{
_Error_Handler(__FILE__, __LINE__);
}

}

/** Configure pins as
* Analog
* Input
* Output
* EVENT_OUT
* EXTI
*/
static void MX_GPIO_Init(void)
{

GPIO_InitTypeDef GPIO_InitStruct;

/* GPIO Ports Clock Enable */
__HAL_RCC_GPIOC_CLK_ENABLE();
__HAL_RCC_GPIOD_CLK_ENABLE();
__HAL_RCC_GPIOA_CLK_ENABLE();

/*Configure GPIO pin Output Level */
HAL_GPIO_WritePin(GPIOC, GPIO_PIN_13, GPIO_PIN_RESET);

/*Configure GPIO pin Output Level */
HAL_GPIO_WritePin(GPIOA, GPIO_PIN_4, GPIO_PIN_RESET);

/*Configure GPIO pin : PC13 */
GPIO_InitStruct.Pin = GPIO_PIN_13;
GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);

/*Configure GPIO pin : PA4 */
GPIO_InitStruct.Pin = GPIO_PIN_4;
GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

}

/* USER CODE BEGIN 4 */

/* USER CODE END 4 */

/**
* @brief This function is executed in case of error occurrence.
* @param None
* @retval None
*/
void _Error_Handler(char * file, int line)
{
/* USER CODE BEGIN Error_Handler_Debug */
/* User can add his own implementation to report the HAL error return state */
while(1)
{
}
/* USER CODE END Error_Handler_Debug */
}

#ifdef USE_FULL_ASSERT

/**
* @brief Reports the name of the source file and the source line number
* where the assert_param error has occurred.
* @param file: pointer to the source file name
* @param line: assert_param error line source number
* @retval None
*/
void assert_failed(uint8_t* file, uint32_t line)
{
/* USER CODE BEGIN 6 */
/* User can add his own implementation to report the file name and line number,
ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
/* USER CODE END 6 */

}

#endif

/**
* @}
*/

/**
* @}
*/

/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/

Most of the code was created by STMCube. Using SPI1, I've connected/assigned:

- PA4(GPIO_Output) to Load(PL_NOT-1)

- PA5(SPI1_SCK) to SCK (CP-2)

- PA7(SPI1_MISO) to Q7(9)

- PAC13(GPIO_Output) to a led

 

I have 5V signal on D0(11) and by requesting with aRxBuffer the value should be aRxBuffer[0]==0x01 right?

 

while (1)
{
/* USER CODE END WHILE */
if(aRxBuffer[0]==0x00)
{
HAL_GPIO_WritePin(GPIOC, GPIO_PIN_13, GPIO_PIN_SET);

}

//Led turns on

The code above works and the leds turns on, however, D0 is high so the buffer value shouldn't be 0x00 but instead 0x01. So why does the led turn on? Similair story when I replace 0x00 to 0x01, the led doesn't turn on, but it should.

 

if(aRxBuffer[0]==0x00)
{
HAL_GPIO_WritePin(GPIOC, GPIO_PIN_13, GPIO_PIN_SET);

}

//Led doesn't turn on

How can I retrieve the value from the 74hc165 correctly and perhaps store it into a variable so I can process it much better?

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