使用的是GD国产芯片目前可以初始化SD卡并读取卡的信息,但是使用f_open函数就一直返回FR_DISK_ERR,
仿真找了发现是这里有问题
/* Find an FAT volume on the hosting drive */
fmt = find_volume(fs, LD2PT(vol));
if (fmt == 4) return FR_DISK_ERR; /* An error occurred in the disk I/O layer */
if (fmt >= 2) return FR_NO_FILESYSTEM; /* No FAT volume is found */
bsect = fs->winsect; /* Volume offset in the hosting physical drive */