Everyone a great god, and we use STM32F407ZE USB U disk, use the punctual in the routines of the atom, process, probably mf_open create an XLS file, - & gt; Sprintf () to format data - & gt; Mf_write writing data to the U disk - & gt; Mf_close documents, written in the U disk read data, it found that there will be garbled, phenomenon is 1 in writing the add or remove several variables can write properly, stack damage is suspected, but couldn't find the problem, the phenomenon of 2 can be normal writing, will write step 4 encapsulated into a single function, in the function call will be garbled words, a great god please help solve!!!!!! Need to send the source code,