找到sd卡写的时候乱码的原因了。

发布于 2010-08-02 22:24:06 浏览：3641 订阅该版

static rt_size_t rt_sdcard_write (rt_device_t dev, rt_off_t pos, const void* buffer, rt_size_t size)
{
	SD_Error status;
	rt_uint32_t nr = size / SECTOR_SIZE;

rt_sem_take(&sd_lock, RT_WAITING_FOREVER);

/* read all sectors */
	if (((rt_uint32_t)buffer % 4 != 0) ||
        ((rt_uint32_t)buffer > 0x20080000))
	{
	    rt_uint32_t index;

/* which is not alignment with 4 or chip SRAM */
        for (index = 0; index < nr; index ++)
        {
            /* copy to the buffer */
            rt_memcpy(_sdcard_buffer, ((rt_uint8_t*)buffer + index * SECTOR_SIZE), SECTOR_SIZE);

status = SD_WriteBlock((part.offset + index) * SECTOR_SIZE + pos,
                (uint32_t*)_sdcard_buffer, SECTOR_SIZE);

if (status != SD_OK) break;
        }
	}
	else
	{
        if (nr == 1)
        {
            status = SD_WriteBlock(part.offset * SECTOR_SIZE + pos,
                (uint32_t*)buffer, SECTOR_SIZE);
        }
        else
        {
            status = SD_WriteMultiBlocks(part.offset * SECTOR_SIZE + pos,
                (uint32_t*)buffer, SECTOR_SIZE, nr);
        }
	}

rt_sem_release(&sd_lock);

if (status == SD_OK) return size;

rt_kprintf("write failed: %d, buffer 0x%08xn", status, buffer);

return 0;
}

这个就是里面的SDIO写函数了，当时候用的时候一直没有注意看，这两天吧sdio驱动弄到asp上，调试了很久，都被gcc优化到城垃圾了，用不了，就一个一个函数测试，突然发现，这个写函数。
注意了。这个函数写的时候最少也是固定512的。所以写的内容没有512，后面就可能出现乱码了。