sd_sample.c

/* * Copyright (c) 2006-2018, RT-Thread Development Team * * SPDX-License-Identifier: Apache-2.0 * * Change Logs: * Date Author Notes * 2018-09-25 misonyo first edition. *//* * 程序清单：这是一个SD卡设备的使用例程 * 例程导出了 sd_sample 命令到控制终端 * 命令调用格式：sd_sample sd0 * 命令解释：命令第二个参数是要使用的SD设备的名称，为空则使用例程默认的SD设备。 * 程序功能：程序会产生一个块大小的随机数，然后写入SD卡中，然后在读取这部分写入的数据。 * 对比写入和读出的数据是否一致，一致则表示程序运行正确。*/#include <rtthread.h>#include <rtdevice.h>#include <stdlib.h>#define SD_DEVICE_NAME "sd0"void fill_buffer(rt_uint8_t *buff, rt_uint32_t buff_length){ rt_uint32_t index; /* 往缓冲区填充随机数 */ for (index = 0; index < buff_length; index++) { buff[index] = ((rt_uint8_t)rand()) & 0xff; }}static int sd_sample(int argc, char *argv[]){ rt_err_t ret; rt_device_t sd_device; char sd_name[RT_NAME_MAX]; rt_uint8_t *write_buff, *read_buff; struct rt_device_blk_geometry geo; rt_uint8_t block_num; /* 判断命令行参数是否给定了设备名称 */ if (argc == 2) { rt_strncpy(sd_name, argv[1], RT_NAME_MAX); } else { rt_strncpy(sd_name, SD_DEVICE_NAME, RT_NAME_MAX); } /* 查找设备获取设备句柄 */ sd_device = rt_device_find(sd_name); if (sd_device == RT_NULL) { rt_kprintf("find device %s failed!\n", sd_name); return RT_ERROR; } /* 打开设备 */ ret = rt_device_open(sd_device, RT_DEVICE_OFLAG_RDWR); if (ret != RT_EOK) { rt_kprintf("open device %s failed!\n", sd_name); return ret; } rt_memset(&geo, 0, sizeof(geo)); /* 获取块设备信息 */ ret = rt_device_control(sd_device, RT_DEVICE_CTRL_BLK_GETGEOME, &geo); if (ret != RT_EOK) { rt_kprintf("control device %s failed!\n", sd_name); return ret; } rt_kprintf("device information:\n"); rt_kprintf("sector size : %d byte\n", geo.bytes_per_sector); rt_kprintf("sector count : %d \n", geo.sector_count); rt_kprintf("block size : %d byte\n", geo.block_size); /* 准备读写缓冲区空间，大小为一个块 */ read_buff = rt_malloc(geo.block_size); if (read_buff == RT_NULL) { rt_kprintf("no memory for read buffer!\n"); return RT_ERROR; } write_buff = rt_malloc(geo.block_size); if (write_buff == RT_NULL) { rt_kprintf("no memory for write buffer!\n"); rt_free(read_buff); return RT_ERROR; } /* 填充写数据缓冲区，为写操作做准备 */ fill_buffer(write_buff, geo.block_size); /* 把写数据缓冲的数据写入SD卡中，大小为一个块，size参数以块为单位 */ block_num = rt_device_write(sd_device, 0, write_buff, 1); if (1 != block_num) { rt_kprintf("write device %s failed!\n", sd_name); } /* 从SD卡中读出数据，并保存在读数据缓冲区中 */ block_num = rt_device_read(sd_device, 0, read_buff, 1); if (1 != block_num) { rt_kprintf("read %s device failed!\n", sd_name); } /* 比较写数据缓冲区和读数据缓冲区的内容是否完全一致 */ if (rt_memcmp(write_buff, read_buff, geo.block_size) == 0) { rt_kprintf("Block test OK!\n"); } else { rt_kprintf("Block test Fail!\n"); } /* 释放缓冲区空间 */ rt_free(read_buff); rt_free(write_buff); return RT_EOK;}/* 导出到 msh 命令列表中 */MSH_CMD_EXPORT(sd_sample, sd device sample);