SWM32系列教程9--SDIO及FatFs文件系統(tǒng)
[導(dǎo)讀]SWM32S單片機有1個SDIO接口，支持多媒體卡（MMC）、SD 存儲卡、SDIO 卡等設(shè)備，可以使用軟件方法或者 DMA 方法（SDIO 模塊內(nèi)部 DMA，與芯片 DMA 模塊無關(guān)）進行數(shù)據(jù)傳輸。
SWM32S單片機有1個SDIO接口，支持多媒體卡（MMC）、SD 存儲卡、SDIO 卡等設(shè)備，可以使用軟件方法或者 DMA 方法（SDIO 模塊內(nèi)部 DMA，與芯片 DMA 模塊無關(guān)）進行數(shù)據(jù)傳輸。其特點如下：
使用起來也比較簡單，相關(guān)的庫函數(shù)已經(jīng)封裝好了，直接調(diào)用就行。 首先需要配置一下相關(guān)引腳的復(fù)用功能為SDIO：
PORT_Init(PORTB, PIN1, PORTB_PIN1_SD_CLK, 0); PORT_Init(PORTB, PIN2, PORTB_PIN2_SD_CMD, 1); PORT_Init(PORTB, PIN3, PORTB_PIN3_SD_D0, 1); PORT_Init(PORTB, PIN4, PORTB_PIN4_SD_D1, 1); PORT_Init(PORTB, PIN5, PORTB_PIN5_SD_D2, 1); PORT_Init(PORTB, PIN6, PORTB_PIN6_SD_D3, 1);
然后直接調(diào)用初始化的函數(shù)就行：
result = SDIO_Init(10000000);
其中形參為SDIO的時鐘頻率。 SD卡讀寫的相關(guān)函數(shù)也已經(jīng)封裝好了，包括DMA和非DMA方式，直接調(diào)用即可：
uint32_t SDIO_BlockWrite(uint32_t block_addr, uint32_t buff[]);uint32_t SDIO_BlockRead(uint32_t block_addr, uint32_t buff[]);uint32_t SDIO_MultiBlockWrite(uint32_t block_addr, uint16_t block_cnt, uint32_t buff[]);uint32_t SDIO_MultiBlockRead(uint32_t block_addr, uint16_t block_cnt, uint32_t buff[]);uint32_t SDIO_DMABlockWrite(uint32_t block_addr, uint16_t block_cnt, uint32_t buff[]);uint32_t SDIO_DMABlockRead(uint32_t block_addr, uint16_t block_cnt, uint32_t buff[]);
2.FatFs移植 底層讀寫函數(shù)有了以后，移植FatFs也就比較簡單了，首先將FatFs的相關(guān)文件添加到工程中：
我們需要實現(xiàn)的接口函數(shù)在diskio.c文件中，包括至少以下3個函數(shù)： 初始化函數(shù)，直接將端口配置、SDIO初始化添加到該函數(shù)中：
DSTATUS disk_initialize ( BYTE pdrv /* Physical drive nmuber to identify the drive */){ DSTATUS stat; int result; switch (pdrv) { case DEV_RAM : //result = RAM_disk_initialize(); // translate the reslut code here stat = STA_NOINIT; return stat; case DEV_MMC : //result = MMC_disk_initialize(); // translate the reslut code here PORT_Init(PORTB, PIN1, PORTB_PIN1_SD_CLK, 0); PORT_Init(PORTB, PIN2, PORTB_PIN2_SD_CMD, 1); PORT_Init(PORTB, PIN3, PORTB_PIN3_SD_D0, 1); PORT_Init(PORTB, PIN4, PORTB_PIN4_SD_D1, 1); PORT_Init(PORTB, PIN5, PORTB_PIN5_SD_D2, 1); PORT_Init(PORTB, PIN6, PORTB_PIN6_SD_D3, 1); result = SDIO_Init(10000000); if(result == SD_RES_OK) stat = RES_OK; sd_initialized = 1; } else { stat = STA_NOINIT; sd_initialized = 0; } return stat; case DEV_USB : //result = USB_disk_initialize(); // translate the reslut code here stat = STA_NOINIT; return stat; } return STA_NOINIT;}讀函數(shù)：
DRESULT disk_read ( BYTE pdrv, /* Physical drive nmuber to identify the drive */ BYTE *buff, /* Data buffer to store read data */ LBA_t sector, /* Start sector in LBA */ UINT count /* Number of sectors to read */){ DRESULT res; int result; switch (pdrv) { case DEV_RAM : // translate the arguments here //result = RAM_disk_read(buff, sector, count); // translate the reslut code here res = RES_PARERR; return res; case DEV_MMC : if(count == 1) { result = SDIO_BlockRead(sector, (uint32_t *)buff); } else { //result = SDIO_MultiBlockRead(sector, count, (uint32_t *)buff); result = SDIO_DMABlockRead(sector, count, (uint32_t *)buff);//使用DMA或非DMA模式均可 } if(result == SD_RES_OK) res = RES_OK; else res = RES_ERROR; return res; case DEV_USB : // translate the arguments here //result = USB_disk_read(buff, sector, count); // translate the reslut code here res = RES_PARERR; return res; } return RES_PARERR;}寫函數(shù)：
DRESULT disk_write ( BYTE pdrv, /* Physical drive nmuber to identify the drive */ const BYTE *buff, /* Data to be written */ LBA_t sector, /* Start sector in LBA */ UINT count /* Number of sectors to write */){ DRESULT res; int result; switch (pdrv) { case DEV_RAM : // translate the arguments here //result = RAM_disk_write(buff, sector, count); // translate the reslut code here res = RES_PARERR; return res; case DEV_MMC : if(count == 1) { result = SDIO_BlockWrite(sector, (uint32_t *)buff); } else { //result = SDIO_MultiBlockWrite(sector, count, (uint32_t *)buff); result = SDIO_DMABlockWrite(sector, count, (uint32_t *)buff);//使用DMA或非DMA模式均可 } if(result == SD_RES_OK) res = RES_OK; else res = RES_ERROR; return res; case DEV_USB : // translate the arguments here //result = USB_disk_write(buff, sector, count); // translate the reslut code here res = RES_PARERR; return res; } return RES_PARERR;}還有一個函數(shù)是用戶獲取SD卡容量等信息的，如下：
DRESULT disk_ioctl ( BYTE pdrv, /* Physical drive nmuber (0..) */ BYTE cmd, /* Control code */ void *buff /* Buffer to send/receive control data */){ DRESULT res; //int result; switch (pdrv) { case DEV_RAM : // Process of the command for the RAM drive res = RES_PARERR; return res; case DEV_MMC : switch ( cmd ) { //fatfs內(nèi)核使用cmd調(diào)用 case GET_SECTOR_COUNT: //sector count *(DWORD*)buff = SD_cardInfo.CardCapacity / 512; return RES_OK; case GET_SECTOR_SIZE: //sector size, 傳入block size(SD),單位bytes *(DWORD*)buff = 512; return RES_OK; case GET_BLOCK_SIZE: //block size, 由上文可得，對于SD2.0卡最大8192，最小 1 *(DWORD*)buff = 1; //單位為 sector(FatFs) return RES_OK; case CTRL_SYNC: //同步命令，貌似FatFs內(nèi)核用來判斷寫操作是否完成 return RES_OK; } res = RES_OK; return res; case DEV_USB : // Process of the command the USB drive res = RES_PARERR; return res; } return RES_PARERR;}接口部分實現(xiàn)后，就可以調(diào)用相關(guān)的函數(shù)實現(xiàn)文件的讀寫了，測試程序如下：
res = f_mount(&fatfs, "sd:", 1);if(res != FR_OK){ printf("sdcard init fail!\r\n");}res = f_open(&filw, "sd:test.txt", FA_CREATE_ALWAYS | FA_WRITE);if(res != FR_OK){ printf("create file fail!\r\n");}res = f_write(&filw, str, strlen(str), &len);if(res != FR_OK){ printf("write file fail!\r\n");}f_close(&filw);
文件系統(tǒng)的配置可以在"ffconf.h"文件中根據(jù)實際需求進行修改。
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