標(biāo)題: 數(shù)據(jù)類型轉(zhuǎn)換unsigned int long char [打印本頁]

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作者: daniu    時(shí)間: 2014-12-26 21:12
標(biāo)題: 數(shù)據(jù)類型轉(zhuǎn)換unsigned int long char

數(shù)據(jù)類型轉(zhuǎn)換unsigned int long char
任務(wù)：怎樣把一個(gè)unsigned int（unsinged long）轉(zhuǎn)換成相應(yīng)的unsigned char，然后從串口發(fā)出？

例如：
extern void put_uchar(unsigned char); //往串口發(fā)送一個(gè)無符號字節(jié)數(shù)
unsigned long a;

a=0x12345678;
put_uchar(((unsigned char *)&a)[0]);//發(fā)出0x78
put_uchar(((unsigned char *)&a)[1]);//發(fā)出0x56
put_uchar(((unsigned char *)&a)[2]);//發(fā)出0x34
put_uchar(((unsigned char *)&a)[3]);//發(fā)出0x12

還有其它方法，但我想這種方法編譯效率最高。

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作者: goer.lu    時(shí)間: 2015-6-26 10:14
那問下如何將unsigned char 轉(zhuǎn)換成unsigned int 呢，例如x = MMA845x_readbyte(OUT_X_MSB_REG);
輸出的X=2556,我需要將X除以256后輸出，可是除以以后輸出就是0了，怎么解決啊

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