STM32 FAT F_READ函数，指针是16位的如何传递超过65535的图片？

dixdsqaid

/*-----------------------------------------------------------------------*/
/* Read File                                                             */
/*-----------------------------------------------------------------------*/

FRESULT f_read (
FIL *fp, /* Pointer to the file object */
void *buff, /* Pointer to data buffer */
UINT btr, /* Number of u8s to read */
UINT *br /* Pointer to number of u8s read */
)
{
FRESULT res;
DWORD sect, remain;
UINT rcnt, cc;
CLUST clust;
u8 *rbuff = buff;


*br = 0;
res = validate(fp->fs, fp->id); /* Check validity of the object */
if (res != FR_OK) return res;
if (fp->flag & FA__ERROR) return FR_RW_ERROR; /* Check error flag */
if (!(fp->flag & FA_READ)) return FR_DENIED; /* Check access mode */
remain = fp->fsize - fp->fptr;
if (btr > remain) btr = (UINT)remain; /* Truncate btr by remaining u8s */

for ( ;  btr; /* Repeat until all data transferred */
rbuff += rcnt, fp->fptr += rcnt, *br += rcnt, btr -= rcnt) {
if ((fp->fptr % 512U) == 0) { /* On the sector boundary? */
if (fp->csect >= fp->fs->csize) { /* On the cluster boundary? */
clust = (fp->fptr == 0) ? /* On the top of the file? */
fp->org_clust : get_cluster(fp->curr_clust);
if (clust < 2 || clust >= fp->fs->max_clust) goto fr_error;
fp->curr_clust = clust; /* Update current cluster */
fp->csect = 0; /* Reset sector address in the cluster */
}
sect = clust2sect(fp->curr_clust) + fp->csect; /* Get current sector */
cc = btr / 512U; /* When remaining u8s >= sector size, */
if (cc) { /* Read maximum contiguous sectors directly */
if (fp->csect + cc > fp->fs->csize) /* Clip at cluster boundary */
cc = fp->fs->csize - fp->csect;
if (disk_read(0, rbuff, sect, (u8)cc) != RES_OK)
goto fr_error;
fp->csect += (u8)cc; /* Next sector address in the cluster */
rcnt = 512U * cc; /* Number of u8s transferred */
continue;
}
fp->csect++; /* Next sector address in the cluster */
}
sect = clust2sect(fp->curr_clust) + fp->csect - 1; /* Get current sector */
if (!move_window(sect)) goto fr_error; /* Move sector window */
rcnt = 512U - (fp->fptr % 512U); /* Get partial sector from sector window */
if (rcnt > btr) rcnt = btr;
memcpy(rbuff, &fp->fs->win[fp->fptr % 512U], rcnt);
}

return FR_OK;

fr_error: /* Abort this file due to an unrecoverable error */
fp->flag |= FA__ERROR;
return FR_RW_ERROR;
}

这是它的固件库代码，从定义来看，传递的RCNT是U16的，怎么做到读取200K的图？

aleda303

分块读 。按65536一块读 ， 多调用几次。