STM32F0 I2C HAL保存結構來I2C EEPROM

Question

我需要一個結構保存：

struct { 
    uint16_t value; 
    uint16_t flag; 
} status; 

到使用

HAL_StatusTypeDef HAL_I2C_Mem_Write (I2C_HandleTypeDef * hi2c, uint16_t DevAddress, uint16_t MemAddress, uint16_t MemAddSize, uint8_t * pData, uint16_t Size, uint32_t Timeout) 

功能

你能建議我一個正確的方式外部I2C EEPROM去做這個？

Answer 1

如果您關閉所有數據類型存儲簡單字節，不同之處在於如何解釋字節。

基本上你需要一個uint8_t* pData指向緩衝區的指針和要傳輸的字節數（uint16_t Size）。所以將結構指針轉換爲uint8_t*並使用sizeof()獲取大小。

這裏是一個模擬，請原諒我我糟糕的測試環境（int s和unsigned char s）。

#include <stdio.h> 
#include <stdlib.h> 
#include <string.h> 

typedef struct { 
    int value; 
    int flag; 
} status; 

int main(void) { 

    status stat; 
    stat.value = 15; 
    stat.flag = 1; 

    int size = sizeof(status);       // number of bytes to be sent 
    unsigned char* pData;         // (uint8_t*) unsigned char* pointer to data 

    unsigned char eeprom[size];       // simulated EEPROM 
    unsigned char pDataReceived[size];     // for read back from EEPROM test 
    status* read_back;         // for read back from EEPROM test 

    printf("%d %d\n", stat.value, stat.flag);    // verify data in original format 

    pData = (unsigned char*)(&stat);      // cast data pointer to (uint8_t*) unsigned char* 
    printf("%d %d\n", ((status*)pData)->value, ((status*)pData)->flag); // verify data after cast 

    memcpy(eeprom, pData, size);       // I2C write bytes simulation 
    printf("%d %d\n", ((status*)eeprom)->value, ((status*)eeprom)->flag); // verify data in simulated EEPROM 

    memcpy(pDataReceived, eeprom, size);     // I2C read bytes simulation 
    read_back = (status*)(pDataReceived);     // cast back to struct type 
    printf("%d %d\n", read_back->value, read_back->flag); // verify received data in original format 

    return 0; 
} 

寫例如：

struct status stat; 
// operations on the struct 
uint8_t* addressOfStruct= (uint8_t*)(&stat); 
uint16_t sizeOfStruct = sizeof(status); 

HAL_StatusTypeDef HAL_I2C_Mem_Write (&hi2c, DevAddress, MemAddress, MemAddSize, addressOfStruct, sizeOfStruct, 100); 

讀例如：

struct status* read; 
uint16_t sizeOfBuffer = sizeof(status); 
uint8_t receiveBuffer[sizeOfBuffer]; 

HAL_StatusTypeDef HAL_I2C_Mem_Read (&hi2c, DevAddress, MemAddress, MemAddSize, receiveBuffer, sizeOfBuffer, 100); 

read = (status*)(receiveBuffer); // or copy or move the data