求教傻孩子 Petit FatFs 的写函数 pf_write（） 数据写不进去，求高手解脱，求例程
Petit FatFs的写函数 pf_write（） 数据写不进去，求高手解脱，求例程其他函数功能都好使就是写不进去求高手 给解释几句呗非常感谢分享个例程就万分感谢了kao 2位论坛的大侠 都要出来给你解答问题////// 抱歉啊我就随便问问啊希望能大家百忙之中 能抽空 看下我的小问题。 ./emotion/em007.gif 需要详细阅读官网中关于pf_write的说明:
File write operation must be done in following sequence.
1.pf_lseek(ofs); read/write pointer must be moved to sector bundary prior to initiate write operation or it will be rounded-down to the sector boundary.
2.pf_write(buff, btw, &bw); Initiate write operation. Write first data to the file.
3.pf_write(buff, btw, &bw); Write next data. Any other file function cannot be used while a write operation is in progress.
4.pf_write(0, 0, &bw); Finalize the write operation. If read/write pointer is not on the sector boundary, left bytes in the sector will be filled with zero.
以下是我测试的一个小例程,供参考,可能不一定全面:
//The following module is to write bytes to txt file.
//Note:it use the new string to replace all of the old bytes.
//For example:the old bytes:123456789abcefg
// 123456789
// the new string:Hello world!
// The result:Hello world!
// Hello world!
rc = pf_open("write.txt");
pf_lseek(rc);
for (;;)
{
rc = pf_write("Hello world!\r\n", 14, &bw);
if (rc || !bw) break;
}
rc = pf_write(0, 0, &bw); //Finalize the write operation.
ClearLED3;
while(1);
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