stm32F0xx USB存储盘设计

来源：网络整理网络用户发布，如有版权联系网管删除　2017-11-30　

第一个USB工程例子：USB存储盘。因为手边没有SPI或I2C接口的Flash, 就权且用单片机的RAM虚拟一下吧。这个"U盘"容量标成160kB, 实际上有效的存储只有10kB，用一点扇区映射的技巧骗过操作系统，当然存放文件只能几kB了。

ST官方提供了一个 STM32F0 的USB固件库，(URL http://www.st.com/st-web-ui/static/active/en/st_prod_software_internet/resource/technical/software/firmware/stsw-stm32092.zip)，包括了硬件库、核心库和类库的C头文件和源文件。我cruelfox琢磨了一整天，还是没搞清楚怎么调用这些函数，只好照着个Example改吧。

于是就用MassStorage类的例子来下手了，这个目录里面的主文件 app.c 非常简单

/**
* @file app.c
*/
/* Includes ------------------------------------------------------------------*/
#include "usbd_msc_core.h"
#include "usbd_usr.h"
USB_CORE_HANDLE USB_Device_dev ;
int main(void)
{
USBD_Init(&USB_Device_dev,
&USR_desc,
&USBD_MSC_cb,
&USR_cb);
while (1)
{
}
}
#ifdef USE_FULL_ASSERT
void assert_failed(uint8_t* file, uint32_t line)
{
while (1)
{}
}
#endif

复制代码

一切USB相关的东西都在 USBD_init() 这个函数里面了。追查源代码，可以发现这个函数调用其实是向库函数提供了一堆回调函数的接口，也就是说写一些子程序，让驱动程序在需要的时候调用。这样开发USB的我们就不用去管中断什么的了，要做的就是实现各种USB的请求——其实程序库里面已经把大部分的请求应答都实现了，而具体的类库(比如我这里用的MassStorage类)又处理了剩余的大部分，所以只剩下功能性的需要自己写。

在 usbd_desc.c 这个程序里面可以看到描述符是怎么创建和返回的

/**
******************************************************************************
* @file usbd_desc.c
* @author MCD Application Team
* @version V1.0.0
* @date 31-January-2014
* @brief This file provides the USBD deｓｃｒｉｐｔors and string formating method.
******************************************************************************
* @attention
*
* <h2><center>© COPYRIGHT 2014 STMicroelectronics</center></h2>
*
* Licensed under MCD-ST Liberty SW License Agreement V2, (the "License");
* You may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.st.com/software_license_agreement_liberty_v2
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
******************************************************************************
*/
/* Includes ------------------------------------------------------------------*/
#include "usbd_desc.h"
/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
#define USBD_VID 0x0483
#define USBD_PID 0x5720
#define USBD_LANGID_STRING 0x409
#define USBD_MANUFACTURER_STRING "STMicroelectronics"
#define USBD_PRODUCT_FS_STRING "Mass Storage in FS Mode"
#define USBD_CONFIGURATION_FS_STRING "MSC Config"
#define USBD_INTERFACE_FS_STRING "MSC Interface"
/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
char USBD_SERIALNUMBER_FS_STRING[26];
USBD_DEVICE USR_desc =
{
USBD_USR_DeviceDeｓｃｒｉｐｔor,
USBD_USR_LangIDStrDeｓｃｒｉｐｔor,
USBD_USR_ManufacturerStrDeｓｃｒｉｐｔor,
USBD_USR_ProductStrDeｓｃｒｉｐｔor,
USBD_USR_SerialStrDeｓｃｒｉｐｔor,
USBD_USR_ConfigStrDeｓｃｒｉｐｔor,
USBD_USR_InterfaceStrDeｓｃｒｉｐｔor,
};
/* USB Standard Device Deｓｃｒｉｐｔor */
const uint8_t USBD_DeviceDesc[USB_SIZ_DEVICE_DESC] =
{
0x12, /*bLength */
USB_DEVICE_DEｓｃｒｉｐｔOR_TYPE, /*bDeｓｃｒｉｐｔorType*/
0x00, /*bcdUSB */
0x02,
0x00, /*bDeviceClass*/
0x00, /*bDeviceSubClass*/
0x00, /*bDeviceProtocol*/
USB_MAX_EP0_SIZE, /*bMaxPacketSize*/
LOBYTE(USBD_VID), /*idVendor*/
HIBYTE(USBD_VID), /*idVendor*/
LOBYTE(USBD_PID), /*idVendor*/
HIBYTE(USBD_PID), /*idVendor*/
0x00, /*bcdDevice rel. 2.00*/
0x02,
USBD_IDX_MFC_STR, /*Index of manufacturer string*/
USBD_IDX_PRODUCT_STR, /*Index of product string*/
USBD_IDX_SERIAL_STR, /*Index of serial number string*/
USBD_CFG_MAX_NUM /*bNumConfigurations*/
} ; /* USB_DeviceDeｓｃｒｉｐｔor */
/* USB Standard Device Deｓｃｒｉｐｔor */
const uint8_t USBD_DeviceQualifierDesc[USB_LEN_DEV_QUALIFIER_DESC] =
{
USB_LEN_DEV_QUALIFIER_DESC,
USB_DESC_TYPE_DEVICE_QUALIFIER,
0x00,
0x02,
0x00,
0x00,
0x00,
0x40,
0x01,
0x00,
};
/* USB Standard Device Deｓｃｒｉｐｔor */
const uint8_t USBD_LangIDDesc[USB_SIZ_STRING_LANGID] =
{
USB_SIZ_STRING_LANGID,
USB_DESC_TYPE_STRING,
LOBYTE(USBD_LANGID_STRING),
HIBYTE(USBD_LANGID_STRING),
};
uint8_t USBD_StringSerial[USB_SIZ_STRING_SERIAL] =
{
USB_SIZ_STRING_SERIAL, /* bLength */
USB_STRING_DEｓｃｒｉｐｔOR_TYPE, /* bDeｓｃｒｉｐｔorType */
};
/* Private function prototypes -----------------------------------------------*/
/* Private functions ---------------------------------------------------------*/
static void IntToUnicode (uint32_t value , uint8_t *pbuf , uint8_t len);
/**
* @brief return the device deｓｃｒｉｐｔor
* @param speed : current device speed
* @param length : pointer to data length variable
* @retval pointer to deｓｃｒｉｐｔor buffer
*/
uint8_t * USBD_USR_DeviceDeｓｃｒｉｐｔor( uint8_t speed , uint16_t *length)
{
*length = sizeof(USBD_DeviceDesc);
return (uint8_t*)USBD_DeviceDesc;
}
/**
* @brief return the LangID string deｓｃｒｉｐｔor
* @param speed : current device speed
* @param length : pointer to data length variable
* @retval pointer to deｓｃｒｉｐｔor buffer
*/
uint8_t * USBD_USR_LangIDStrDeｓｃｒｉｐｔor( uint8_t speed , uint16_t *length)
{
*length = sizeof(USBD_LangIDDesc);
return (uint8_t*)USBD_LangIDDesc;
}
/**
* @brief return the product string deｓｃｒｉｐｔor
* @param speed : current device speed
* @param length : pointer to data length variable
* @retval pointer to deｓｃｒｉｐｔor buffer
*/
uint8_t * USBD_USR_ProductStrDeｓｃｒｉｐｔor( uint8_t speed , uint16_t *length)
{
USBD_GetString ( (uint8_t*)USBD_PRODUCT_FS_STRING, USBD_StrDesc, length);
return USBD_StrDesc;
}
/**
* @brief return the manufacturer string deｓｃｒｉｐｔor
* @param speed : current device speed
* @param length : pointer to data length variable
* @retval pointer to deｓｃｒｉｐｔor buffer
*/
uint8_t * USBD_USR_ManufacturerStrDeｓｃｒｉｐｔor( uint8_t speed , uint16_t *length)
{
USBD_GetString ( (uint8_t*)USBD_MANUFACTURER_STRING, USBD_StrDesc, length);
return USBD_StrDesc;
}
/**
* @brief return the serial number string deｓｃｒｉｐｔor
* @param speed : current device speed
* @param length : pointer to data length variable
* @retval pointer to deｓｃｒｉｐｔor buffer
*/
uint8_t * USBD_USR_SerialStrDeｓｃｒｉｐｔor( uint8_t speed , uint16_t *length)
{
*length = USB_SIZ_STRING_SERIAL;
return USBD_StringSerial;
}
/**
* @brief return the configuration string deｓｃｒｉｐｔor
* @param speed : current device speed
* @param length : pointer to data length variable
* @retval pointer to deｓｃｒｉｐｔor buffer
*/
uint8_t * USBD_USR_ConfigStrDeｓｃｒｉｐｔor( uint8_t speed , uint16_t *length)
{
USBD_GetString ( (uint8_t*)USBD_CONFIGURATION_FS_STRING, USBD_StrDesc, length);
return USBD_StrDesc;
}
/**
* @brief return the interface string deｓｃｒｉｐｔor
* @param speed : current device speed
* @param length : pointer to data length variable
* @retval pointer to deｓｃｒｉｐｔor buffer
*/
uint8_t * USBD_USR_InterfaceStrDeｓｃｒｉｐｔor( uint8_t speed , uint16_t *length)
{
USBD_GetString ( (uint8_t*)USBD_INTERFACE_FS_STRING, USBD_StrDesc, length);
return USBD_StrDesc;
}
/**
* @brief Create the serial number string deｓｃｒｉｐｔor
* @param None
* @retval None
*/
void Get_SerialNum(void)
{
uint32_t Device_Serial0, Device_Serial1, Device_Serial2;
Device_Serial0 = *(uint32_t*)Device1_Identifier;
Device_Serial1 = *(uint32_t*)Device2_Identifier;
Device_Serial2 = *(uint32_t*)Device3_Identifier;
Device_Serial0 += Device_Serial2;
if (Device_Serial0 != 0)
{
IntToUnicode (Device_Serial0, &USBD_StringSerial[2] ,8);
IntToUnicode (Device_Serial1, &USBD_StringSerial[18] ,4);
}
}
/**
* @brief Convert Hex 32Bits value into char
* @param value: value to convert
* @param pbuf: pointer to the buffer
* @param len: buffer length
* @retval None
*/
static void IntToUnicode (uint32_t value , uint8_t *pbuf , uint8_t len)
{
uint8_t idx = 0;
for( idx = 0 ; idx < len ; idx ++)
{
if( ((value >> 28)) < 0xA )
{
pbuf[ 2* idx] = (value >> 28) + '0';
}
else
{
pbuf[2* idx] = (value >> 28) + 'A' - 10;
}
value = value << 4;
pbuf[ 2* idx + 1] = 0;
}
}
/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/

复制代码

插一句: 开发USB设备，有很重要的一部分是编写描述符（当然也要借用已有的模板），设备叫什么，功能是什么等等都从描述符体现。只要设备向主机成功返回了描述符，主机就会提示找到硬件。

设计到U盘读写操作的部分在 usbd_storage_msd.c 里面，我就是在例子程序上改的

/**
******************************************************************************
* @file usbd_storage_msd.c
* @author MCD application Team
* @version V1.0.0
* @date 31-January-2014
* @brief This file provides the disk operations functions.
******************************************************************************
* @attention
*
* <h2><center>© COPYRIGHT 2014 STMicroelectronics</center></h2>
*
* Licensed under MCD-ST Liberty SW License Agreement V2, (the "License");
* You may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.st.com/software_license_agreement_liberty_v2
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
******************************************************************************
*/
#include <string.h>
/* Includes ------------------------------------------------------------------*/
#include "usbd_msc_mem.h"
/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
#define STORAGE_LUN_NBR 1
/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
/* USB Mass storage Standard Inquiry Data */
const int8_t STORAGE_Inquirydata[] = {
/* LUN 0 */
0x00,
0x80,
0x02,
0x02,
(USBD_STD_INQUIRY_LENGTH - 5),
0x00,
0x00,
0x00,
'S', 'T', 'M', ' ', ' ', ' ', ' ', ' ', /* Manufacturer : 8 bytes */
'm', 'i', 'c', 'r', 'o', 'S', 'D', ' ', /* Product : 16 Bytes */
'F', 'l', 'a', 's', 'h', ' ', ' ', ' ',
'1', '.', '0' ,'0', /* Version : 4 Bytes */
};
__IO uint32_t count = 0;
/* Private function prototypes -----------------------------------------------*/
int8_t STORAGE_Init (uint8_t lun);
int8_t STORAGE_GetCapacity (uint8_t lun,
uint32_t *block_num,
uint32_t *block_size);
int8_t STORAGE_IsReady (uint8_t lun);
int8_t STORAGE_IsWriteProtected (uint8_t lun);
int8_t STORAGE_Read (uint8_t lun,
uint8_t *buf,
uint32_t blk_addr,
uint16_t blk_len);
int8_t STORAGE_Write (uint8_t lun,
uint8_t *buf,
uint32_t blk_addr,
uint16_t blk_len);
int8_t STORAGE_GetMaxLun (void);
USBD_STORAGE_cb_TypeDef USBD_MICRO_SDIO_fops =
{
STORAGE_Init,
STORAGE_GetCapacity,
STORAGE_IsReady,
STORAGE_IsWriteProtected,
STORAGE_Read,
STORAGE_Write,
STORAGE_GetMaxLun,
(int8_t *)STORAGE_Inquirydata,
};
USBD_STORAGE_cb_TypeDef *USBD_STORAGE_fops = &USBD_MICRO_SDIO_fops;
/* Private functions ---------------------------------------------------------*/
/**
* @brief Initialize the storage medium
* @param lun : logical unit number
* @retval Status
*/
uint8_t dummy_disk[20][512];
uint16_t sec_index[20]; // sector usage
int8_t STORAGE_Init (uint8_t lun)
{
static char init=0;
if(!init)
{
short int i;
for(i=0;i<20;i++)
sec_index[i]=0xffff;
init=1;
}
return (0);
}
/**
* @brief return medium capacity and block size
* @param lun : logical unit number
* @param block_num : number of physical block
* @param block_size : size of a physical block
* @retval Status
*/
int8_t STORAGE_GetCapacity (uint8_t lun, uint32_t *block_num, uint32_t *block_size)
{
*block_size = 512;
*block_num = 40*9;
return (0);
}
/**
* @brief check whether the medium is ready
* @param lun : logical unit number
* @retval Status
*/
int8_t STORAGE_IsReady (uint8_t lun)
{
static uint8_t status = 0;
return (0);
}
/**
* @brief check whether the medium is write-protected
* @param lun : logical unit number
* @retval Status
*/
int8_t STORAGE_IsWriteProtected (uint8_t lun)
{
return 0;
}
/**
* @brief Read data from the medium
* @param lun : logical unit number
* @param buf : Pointer to the buffer to save data
* @param blk_addr : address of 1st block to be read
* @param blk_len : number of blocks to be read
* @retval Status
*/
int8_t STORAGE_Read (uint8_t lun,
uint8_t *buf,
uint32_t blk_addr,
uint16_t blk_len)
{
short int i;
for(i=0;i<blk_len;i++)
{
short int j;
for(j=0;j<20;j++)
{
if(sec_index[j]==blk_addr+i)
{
memcpy(buf+i*512,dummy_disk[j],512);
break;
}
}
if(j>=20)
{
for(j=0;j<512;j++)
buf[i*512+j]=0x00;
}
}
/* if( SD_ReadMultiBlocks (buf,
blk_addr * 512,
512,
blk_len) != 0)
{
return 5;
}
*/
return 0;
}
/**
* @brief Write data to the medium
* @param lun : logical unit number
* @param buf : Pointer to the buffer to write from
* @param blk_addr : address of 1st block to be written
* @param blk_len : number of blocks to be read
* @retval Status
*/
int8_t STORAGE_Write (uint8_t lun,
uint8_t *buf,
uint32_t blk_addr,
uint16_t blk_len)
{
short int i;
for(i=0;i<blk_len;i++)
{
short int j;
char zero=1;
unsigned char avail=0xff;
for(j=0;j<512;j++)
if(buf[j+i*512])
zero=0;
for(j=0;j<20;j++)
{
if(sec_index[j]==blk_addr+i)
break;
if(avail==0xff && sec_index[j]==0xffff)
avail=j;
}
if(zero)
{
if(j<20)
sec_index[j]=0xffff; // free
return 0;
}
if(j>=20)
{
if(avail<20)
j=avail;
else // No free sectors
{
j=1+rand()%19;
}
}
memcpy(dummy_disk[j],buf+i*512,512);
sec_index[j]=blk_addr+i;
}
return (0);
}
/**
* @brief Return number of supported logical unit
* @param None
* @retval number of logical unit
*/
int8_t STORAGE_GetMaxLun (void)
{
return (STORAGE_LUN_NBR - 1);
}
/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/

复制代码

主要是需要完成报告容量、读、写三个函数。如果有可实现存储的硬件，接口连起来即可。我上面是用了10kB的RAM来存放，动态分配20个扇区来存储。如果检测到要写的整个扇区都是0，那么就忽略。于是这样就做成了虚拟的U盘。

附件包含了所有需要的程序源代码，USB库的部分在lib子目录下面。build.bat 中是编译的命令。依靠这个USB函数库开发起来还算不难吧，只要看懂了例子，mass storage class还比较简单，因为硬件涉及就是读扇区、写扇区。 USB HID设备五花八门，就不是这么简单了，继续研究去。

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游客	2018-09-01 15:22:52
[color=#000000]stm32F042做usb价格高了一点。[/color]//回复：@匿名: 用stm32F042做usb接口还是很方便的，stm编译器的库很好用

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