如何将unsigned int转换为unsigned char

像这样的?

uint32_t value = mcu_read(pin);
uint8_t* bytes = (uint8_t*)(&value);
uint8_t byte_0 = bytes[0];
uint8_t byte_1 = bytes[1];
uint8_t byte_2 = bytes[2];
uint8_t byte_3 = bytes[3];

小心菊苣

您可以使用 bit shift and logical and 以下内容:

uint32_t value = mcu_read(pin);
uint8_t byte_0 = (value >> 24) & 0xFF;
uint8_t byte_1 = (value >> 16) & 0xFF;
uint8_t byte_2 = (value >> 8) & 0xFF;
uint8_t byte_3 = (value) & 0xFF;

#include <stdio.h>
#include <stdint.h>

int main()
{
    uint32_t value = 0xAABBCCDD;
    //-------------------------------
    //byte3 | byte2 | byte1 | byte0 | 
    //-------------------------------
    uint8_t byte_0 = (uint8_t)value; //truncation according to casting rules
    printf("first byte: %x\n",byte_0);
    value>>=8; //right shift will result in the following bytes:
    //-------------------------------
    // garbage | byte3 | byte2 | byte1 | 
    //-------------------------------
    uint8_t byte_1 = (uint8_t)value;
    printf("second byte: %x\n ",byte_1);
    value>>=8;
    //etc...
}

输出:

first byte: dd
second byte: cc