Eli Hughes
test
Diff: diskio.c
- Revision:
- 1:68378811b1e2
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/diskio.c Mon Jan 10 15:02:22 2011 +0000
@@ -0,0 +1,300 @@
+/*-----------------------------------------------------------------------*/
+/* Low level disk I/O module skeleton for FatFs (C)ChaN, 2007 */
+/*-----------------------------------------------------------------------*/
+/* This is a stub disk I/O module that acts as front end of the existing */
+/* disk I/O modules and attach it to FatFs module with common interface. */
+/*-----------------------------------------------------------------------*/
+
+#include "diskio.h"
+#include "mbed.h"
+
+
+//******************************************************************************************************************
+// MBED SPI/CS Select functions.... Modify for your layout.
+//**************************************************************************************
+
+SPI _spi(p5, p6, p7); // mosi, miso, sclk
+DigitalOut _cs(p8);
+
+//******************************************************************************************************************
+// Low Level Sector Access Function Prototypes('C' Castrated versions of Simon Ford's C++ MBED SDFileSystem class
+//******************************************************************************************************************
+int _cmd(int cmd, int arg);
+int _read(BYTE *buffer, int length);
+int _write(BYTE *buffer, int length);
+int ext_bits(BYTE *data, int msb, int lsb);
+int _sd_sectors();
+int _sectors;
+
+#define SD_COMMAND_TIMEOUT 5000
+
+
+//******************************************************************************************************************
+// Sector Access functions for CHAN FatFs
+//******************************************************************************************************************
+
+DRESULT disk_ioctl (
+ BYTE drv, /* Physical drive nmuber (0..) */
+ BYTE ctrl, /* Control code */
+ void *buff /* Buffer to send/receive control data */
+)
+{
+ DRESULT res;
+
+ switch(ctrl)
+ {
+ case CTRL_SYNC:
+ res = RES_OK;
+ break;
+
+ case GET_SECTOR_SIZE:
+ res = RES_OK;
+ *(WORD *)buff = 512;
+ break;
+
+ case GET_SECTOR_COUNT:
+ res = RES_OK;
+ *(DWORD *)buff = (WORD)_sd_sectors();
+ break;
+
+ case GET_BLOCK_SIZE:
+ res = RES_OK;
+ *(DWORD *)buff = 1;
+ break;
+
+ default:
+ res = RES_OK;
+ break;
+ }
+ return res;
+}
+
+DSTATUS disk_initialize(BYTE Drive) {
+
+ _spi.frequency(100000); // Set to 100kHz for initialisation
+
+ // Initialise the card by clocking it a bit (cs = 1)
+ for(int i=0; i<16; i++) {
+ _spi.write(0xFF);
+ }
+
+ // send CMD0, should return with all zeros except IDLE STATE set (bit 0)
+ if(_cmd(0, 0) != 0x01) {
+ fprintf(stderr, "Not in idle state\n");
+ return STA_NOINIT;
+ }
+
+ // ACMD41 to give host capacity support (repeat until not busy)
+ // ACMD41 is application specific command, so we send APP_CMD (CMD55) beforehand
+ for(int i=0;; i++) {
+ _cmd(55, 0);
+ int response = _cmd(41, 0);
+ if(response == 0) {
+ break;
+ } else if(i > SD_COMMAND_TIMEOUT) {
+ fprintf(stderr, "Timeout waiting for card\n");
+ return STA_NOINIT;
+ }
+ }
+
+ _sectors = _sd_sectors();
+
+ // Set block length to 512 (CMD16)
+ if(_cmd(16, 512) != 0) {
+ fprintf(stderr, "Set block timeout\n");
+ return STA_NOINIT;
+ }
+
+ _spi.frequency(10000000); // Set to 10MHz for data transfer
+ return 0;
+}
+
+DRESULT disk_write(BYTE Drive,const BYTE * Buffer, DWORD SectorNumber, BYTE SectorCount)
+{
+ BYTE i;
+
+ BYTE * MyBufOut = (BYTE *)Buffer;
+
+ for(i=0;i<SectorCount;i++)
+ {
+ // set write address for single block (CMD24)
+ if(_cmd(24, (SectorNumber + i) * 512 ) != 0) {
+ return RES_ERROR;
+ }
+
+ // send the data block
+ _write(MyBufOut, 512);
+
+ MyBufOut+=512;
+ }
+ return RES_OK;
+}
+
+DRESULT disk_read(BYTE Drive, BYTE * Buffer,DWORD SectorNumber, BYTE SectorCount)
+{
+ BYTE i;
+ for(i=0;i<SectorCount;i++)
+ {
+ // set read address for single block (CMD17)
+ if(_cmd(17, (SectorNumber+i) * 512) != 0)
+ {
+ return RES_ERROR;
+ }
+ // receive the data
+ _read(Buffer, 512);
+
+ Buffer+=512;
+ }
+ return RES_OK;
+}
+
+
+DWORD get_fattime(void)
+{
+ time_t CurrentTimeStamp;
+ tm *CurrentLocalTime;
+ DWORD FATFSTimeCode;
+
+ CurrentTimeStamp = time(NULL);
+ CurrentLocalTime = localtime(&CurrentTimeStamp);
+
+ //Map the tm struct time into the FatFs time code
+ FATFSTimeCode = ((CurrentLocalTime->tm_year-80)<<25) |
+ ((CurrentLocalTime->tm_mon+1)<<21) |
+ ((CurrentLocalTime->tm_mday)<<16) |
+ ((CurrentLocalTime->tm_hour)<<11) |
+ ((CurrentLocalTime->tm_min)<<5) |
+ ((CurrentLocalTime->tm_sec));
+
+ return FATFSTimeCode;
+}
+
+DSTATUS disk_status(BYTE Drive)
+{
+ return 0;
+}
+
+//**************************************************************************************
+// Low Level Sector Access Functions (Castrated versions of Simon Fords C++ MBED class
+//**************************************************************************************
+
+int _cmd(int cmd, int arg) {
+ _cs = 0;
+
+ // send a command
+ _spi.write(0x40 | cmd);
+ _spi.write(arg >> 24);
+ _spi.write(arg >> 16);
+ _spi.write(arg >> 8);
+ _spi.write(arg >> 0);
+ _spi.write(0x95);
+
+ // wait for the repsonse (response[7] == 0)
+ for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
+ int response = _spi.write(0xFF);
+ if(!(response & 0x80)) {
+ _cs = 1;
+ return response;
+ }
+ }
+ _cs = 1;
+ return -1; // timeout
+}
+
+int _read(BYTE *buffer, int length) {
+ _cs = 0;
+
+ // read until start byte (0xFF)
+ while(_spi.write(0xFF) != 0xFE);
+
+ // read data
+ for(int i=0; i<length; i++) {
+ buffer[i] = _spi.write(0xFF);
+ }
+ _spi.write(0xFF); // checksum
+ _spi.write(0xFF);
+
+ _cs = 1;
+ return 0;
+}
+
+int _write(BYTE *buffer, int length) {
+ _cs = 0;
+
+ // indicate start of block
+ _spi.write(0xFE);
+
+ // write the data
+ for(int i=0; i<length; i++) {
+ _spi.write(buffer[i]);
+ }
+
+ // write the checksum
+ _spi.write(0xFF);
+ _spi.write(0xFF);
+
+ // check the repsonse token
+ if((_spi.write(0xFF) & 0x1F) != 0x05) {
+ _cs = 1;
+ return 1;
+ }
+
+ // wait for write to finish
+ while(_spi.write(0xFF) == 0);
+
+ _cs = 1;
+ return 0;
+}
+
+int ext_bits(BYTE *data, int msb, int lsb) {
+ int bits = 0;
+ int size = 1 + msb - lsb;
+ for(int i=0; i<size; i++) {
+ int position = lsb + i;
+ int byte = 15 - (position >> 3);
+ int bit = position & 0x7;
+ int value = (data[byte] >> bit) & 1;
+ bits |= value << i;
+ }
+ return bits;
+}
+
+int _sd_sectors() {
+
+ // CMD9, Response R2 (R1 byte + 16-byte block read)
+ if(_cmd(9, 0) != 0) {
+ fprintf(stderr, "Didn't get a response from the disk\n");
+ return 0;
+ }
+
+ BYTE csd[16];
+ if(_read(csd, 16) != 0) {
+ fprintf(stderr, "Couldn't read csd response from disk\n");
+ return 0;
+ }
+
+ // csd_structure : csd[127:126]
+ // c_size : csd[73:62]
+ // c_size_mult : csd[49:47]
+ // read_bl_len : csd[83:80]
+
+ int csd_structure = ext_bits(csd, 127, 126);
+ int c_size = ext_bits(csd, 73, 62);
+ int c_size_mult = ext_bits(csd, 49, 47);
+ int read_bl_len = ext_bits(csd, 83, 80);
+
+ if(csd_structure != 0) {
+ fprintf(stderr, "This disk tastes funny! I only know about type 0 CSD structures");
+ return 0;
+ }
+
+ int blocks = (c_size + 1) * (1 << (c_size_mult + 2));
+ int block_size = 1 << read_bl_len;
+
+ if(block_size != 512) {
+ fprintf(stderr, "This disk tastes funny! I only like 512 byte blocks (%d)\r\n",block_size);
+ return 0;
+ }
+
+ return blocks;
+}