test

Dependencies:   FATFileSystem

Files at this revision

API Documentation at this revision

Comitter:
MuroMoe
Date:
Wed Nov 06 07:15:58 2019 +0000
Commit message:
ex

Changed in this revision

FATFileSystem.lib Show annotated file Show diff for this revision Revisions of this file
SDFileSystem.cpp Show annotated file Show diff for this revision Revisions of this file
SDFileSystem.h Show annotated file Show diff for this revision Revisions of this file
diff -r 000000000000 -r 36610d84d988 FATFileSystem.lib
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/FATFileSystem.lib	Wed Nov 06 07:15:58 2019 +0000
@@ -0,0 +1,1 @@
+https://os.mbed.com/users/mkilivan/code/FATFileSystem/#b864b021fc6d
diff -r 000000000000 -r 36610d84d988 SDFileSystem.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SDFileSystem.cpp	Wed Nov 06 07:15:58 2019 +0000
@@ -0,0 +1,441 @@
+/* mbed Microcontroller Library - SDFileSystem
+ * Copyright (c) 2008-2009, sford
+ */
+ 
+// VERY DRAFT CODE! Needs serious rework/refactoring 
+ 
+/* Introduction
+ * ------------
+ * SD and MMC cards support a number of interfaces, but common to them all
+ * is one based on SPI. This is the one I'm implmenting because it means
+ * it is much more portable even though not so performant, and we already 
+ * have the mbed SPI Interface!
+ *
+ * The main reference I'm using is Chapter 7, "SPI Mode" of: 
+ *  http://www.sdcard.org/developers/tech/sdcard/pls/Simplified_Physical_Layer_Spec.pdf
+ *
+ * SPI Startup
+ * -----------
+ * The SD card powers up in SD mode. The SPI interface mode is selected by
+ * asserting CS low and sending the reset command (CMD0). The card will 
+ * respond with a (R1) response.
+ *
+ * CMD8 is optionally sent to determine the voltage range supported, and 
+ * indirectly determine whether it is a version 1.x SD/non-SD card or 
+ * version 2.x. I'll just ignore this for now.
+ *
+ * ACMD41 is repeatedly issued to initialise the card, until "in idle"
+ * (bit 0) of the R1 response goes to '0', indicating it is initialised.
+ *
+ * You should also indicate whether the host supports High Capicity cards,
+ * and check whether the card is high capacity - i'll also ignore this
+ *
+ * SPI Protocol
+ * ------------
+ * The SD SPI protocol is based on transactions made up of 8-bit words, with
+ * the host starting every bus transaction by asserting the CS signal low. The
+ * card always responds to commands, data blocks and errors.
+ * 
+ * The protocol supports a CRC, but by default it is off (except for the 
+ * first reset CMD0, where the CRC can just be pre-calculated, and CMD8)
+ * I'll leave the CRC off I think! 
+ * 
+ * Standard capacity cards have variable data block sizes, whereas High 
+ * Capacity cards fix the size of data block to 512 bytes. I'll therefore
+ * just always use the Standard Capacity cards with a block size of 512 bytes.
+ * This is set with CMD16.
+ *
+ * You can read and write single blocks (CMD17, CMD25) or multiple blocks 
+ * (CMD18, CMD25). For simplicity, I'll just use single block accesses. When
+ * the card gets a read command, it responds with a response token, and then 
+ * a data token or an error.
+ * 
+ * SPI Command Format
+ * ------------------
+ * Commands are 6-bytes long, containing the command, 32-bit argument, and CRC.
+ *
+ * +---------------+------------+------------+-----------+----------+--------------+
+ * | 01 | cmd[5:0] | arg[31:24] | arg[23:16] | arg[15:8] | arg[7:0] | crc[6:0] | 1 |
+ * +---------------+------------+------------+-----------+----------+--------------+
+ *
+ * As I'm not using CRC, I can fix that byte to what is needed for CMD0 (0x95)
+ *
+ * All Application Specific commands shall be preceded with APP_CMD (CMD55).
+ *
+ * SPI Response Format
+ * -------------------
+ * The main response format (R1) is a status byte (normally zero). Key flags:
+ *  idle - 1 if the card is in an idle state/initialising 
+ *  cmd  - 1 if an illegal command code was detected
+ *
+ *    +-------------------------------------------------+
+ * R1 | 0 | arg | addr | seq | crc | cmd | erase | idle |
+ *    +-------------------------------------------------+
+ *
+ * R1b is the same, except it is followed by a busy signal (zeros) until
+ * the first non-zero byte when it is ready again.
+ *
+ * Data Response Token
+ * -------------------
+ * Every data block written to the card is acknowledged by a byte 
+ * response token
+ *
+ * +----------------------+
+ * | xxx | 0 | status | 1 |
+ * +----------------------+
+ *              010 - OK!
+ *              101 - CRC Error
+ *              110 - Write Error
+ *
+ * Single Block Read and Write
+ * ---------------------------
+ *
+ * Block transfers have a byte header, followed by the data, followed
+ * by a 16-bit CRC. In our case, the data will always be 512 bytes.
+ *  
+ * +------+---------+---------+- -  - -+---------+-----------+----------+
+ * | 0xFE | data[0] | data[1] |        | data[n] | crc[15:8] | crc[7:0] | 
+ * +------+---------+---------+- -  - -+---------+-----------+----------+
+ */
+ 
+#include "SDFileSystem.h"
+
+#define SD_COMMAND_TIMEOUT 5000
+
+SDFileSystem::SDFileSystem(PinName mosi, PinName miso, PinName sclk, PinName cs, const char* name) :
+  FATFileSystem(name), _spi(mosi, miso, sclk), _cs(cs) {
+      _cs = 1; 
+}
+
+#define R1_IDLE_STATE           (1 << 0)
+#define R1_ERASE_RESET          (1 << 1)
+#define R1_ILLEGAL_COMMAND      (1 << 2)
+#define R1_COM_CRC_ERROR        (1 << 3)
+#define R1_ERASE_SEQUENCE_ERROR (1 << 4)
+#define R1_ADDRESS_ERROR        (1 << 5)
+#define R1_PARAMETER_ERROR      (1 << 6)
+
+// Types
+//  - v1.x Standard Capacity
+//  - v2.x Standard Capacity
+//  - v2.x High Capacity
+//  - Not recognised as an SD Card
+
+#define SDCARD_FAIL 0
+#define SDCARD_V1   1
+#define SDCARD_V2   2
+#define SDCARD_V2HC 3
+
+int SDFileSystem::initialise_card() {
+    // Set to 100kHz for initialisation, and clock card with cs = 1
+    _spi.frequency(100000); 
+    _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) != R1_IDLE_STATE) { 
+        fprintf(stderr, "No disk, or could not put SD card in to SPI idle state\n");
+        return SDCARD_FAIL;
+    }
+
+    // send CMD8 to determine whther it is ver 2.x
+    int r = _cmd8();
+    if(r == R1_IDLE_STATE) {
+        return initialise_card_v2();
+    } else if(r == (R1_IDLE_STATE | R1_ILLEGAL_COMMAND)) {
+        return initialise_card_v1();
+    } else {
+        fprintf(stderr, "Not in idle state after sending CMD8 (not an SD card?)\n");
+        return SDCARD_FAIL;
+    }
+}
+
+int SDFileSystem::initialise_card_v1() {
+    for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
+        _cmd(55, 0); 
+        if(_cmd(41, 0) == 0) { 
+            return SDCARD_V1;
+        }
+    }
+
+    fprintf(stderr, "Timeout waiting for v1.x card\n");
+    return SDCARD_FAIL;
+}
+
+int SDFileSystem::initialise_card_v2() {
+    
+    for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
+        _cmd(55, 0); 
+        if(_cmd(41, 0) == 0) { 
+            _cmd58();
+            return SDCARD_V2;
+        }
+    }
+
+    fprintf(stderr, "Timeout waiting for v2.x card\n");
+    return SDCARD_FAIL;
+}
+
+int SDFileSystem::disk_initialize() {
+
+    int i = initialise_card();
+//    printf("init card = %d\n", i);
+//    printf("OK\n");
+
+    _sectors = _sd_sectors();
+
+    // Set block length to 512 (CMD16)
+    if(_cmd(16, 512) != 0) {
+        fprintf(stderr, "Set 512-byte block timed out\n");
+        return 1;
+    }
+        
+    _spi.frequency(1000000); // Set to 1MHz for data transfer
+    return 0;
+}
+
+int SDFileSystem::disk_write(const char *buffer, int block_number) {
+    // set write address for single block (CMD24)
+    if(_cmd(24, block_number * 512) != 0) {
+        return 1;
+    }
+
+    // send the data block
+    _write(buffer, 512);    
+    return 0;    
+}
+
+int SDFileSystem::disk_read(char *buffer, int block_number) {        
+    // set read address for single block (CMD17)
+    if(_cmd(17, block_number * 512) != 0) {
+        return 1;
+    }
+    
+    // receive the data
+    _read(buffer, 512);
+    return 0;
+}
+
+int SDFileSystem::disk_status() { return 0; }
+int SDFileSystem::disk_sync() { return 0; }
+int SDFileSystem::disk_sectors() { return _sectors; }
+
+// PRIVATE FUNCTIONS
+
+int SDFileSystem::_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;
+            _spi.write(0xFF);
+            return response;
+        }
+    }
+    _cs = 1;
+    _spi.write(0xFF);
+    return -1; // timeout
+}
+int SDFileSystem::_cmdx(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)) {
+            return response;
+        }
+    }
+    _cs = 1;
+    _spi.write(0xFF);
+    return -1; // timeout
+}
+
+
+int SDFileSystem::_cmd58() {
+    _cs = 0; 
+    int arg = 0;
+    
+    // send a command
+    _spi.write(0x40 | 58);
+    _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)) {
+            int ocr = _spi.write(0xFF) << 24;
+            ocr |= _spi.write(0xFF) << 16;
+            ocr |= _spi.write(0xFF) << 8;
+            ocr |= _spi.write(0xFF) << 0;
+//            printf("OCR = 0x%08X\n", ocr);
+            _cs = 1;
+            _spi.write(0xFF);
+            return response;
+        }
+    }
+    _cs = 1;
+    _spi.write(0xFF);
+    return -1; // timeout
+}
+
+int SDFileSystem::_cmd8() {
+    _cs = 0; 
+    
+    // send a command
+    _spi.write(0x40 | 8); // CMD8
+    _spi.write(0x00);     // reserved
+    _spi.write(0x00);     // reserved
+    _spi.write(0x01);     // 3.3v
+    _spi.write(0xAA);     // check pattern
+    _spi.write(0x87);     // crc
+
+    // wait for the repsonse (response[7] == 0)
+    for(int i=0; i<SD_COMMAND_TIMEOUT * 1000; i++) {
+        char response[5];
+        response[0] = _spi.write(0xFF);
+        if(!(response[0] & 0x80)) {
+                for(int j=1; j<5; j++) {
+                    response[i] = _spi.write(0xFF);
+                }
+                _cs = 1;
+                _spi.write(0xFF);
+                return response[0];
+        }
+    }
+    _cs = 1;
+    _spi.write(0xFF);
+    return -1; // timeout
+}
+
+int SDFileSystem::_read(char *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;    
+    _spi.write(0xFF);
+    return 0;
+}
+
+int SDFileSystem::_write(const char *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;
+        _spi.write(0xFF);        
+        return 1;
+    }
+
+    // wait for write to finish
+    while(_spi.write(0xFF) == 0);
+
+    _cs = 1; 
+    _spi.write(0xFF);
+    return 0;
+}
+
+static int ext_bits(char *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 SDFileSystem::_sd_sectors() {
+
+    // CMD9, Response R2 (R1 byte + 16-byte block read)
+    if(_cmdx(9, 0) != 0) {
+        fprintf(stderr, "Didn't get a response from the disk\n");
+        return 0;
+    }
+    
+    char 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] - the *maximum* read block length
+
+    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);
+
+//    printf("CSD_STRUCT = %d\n", csd_structure);
+    
+    if(csd_structure != 0) {
+        fprintf(stderr, "This disk tastes funny! I only know about type 0 CSD structures\n");
+        return 0;
+    }
+             
+    // memory capacity = BLOCKNR * BLOCK_LEN
+    // where
+    //  BLOCKNR = (C_SIZE+1) * MULT
+    //  MULT = 2^(C_SIZE_MULT+2) (C_SIZE_MULT < 8)
+    //  BLOCK_LEN = 2^READ_BL_LEN, (READ_BL_LEN < 12)         
+                            
+    int block_len = 1 << read_bl_len;
+    int mult = 1 << (c_size_mult + 2);
+    int blocknr = (c_size + 1) * mult;
+    int capacity = blocknr * block_len;
+        
+    int blocks = capacity / 512;
+        
+    return blocks;
+}
\ No newline at end of file
diff -r 000000000000 -r 36610d84d988 SDFileSystem.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SDFileSystem.h	Wed Nov 06 07:15:58 2019 +0000
@@ -0,0 +1,66 @@
+/* mbed Microcontroller Library - SDFileSystem
+ * Copyright (c) 2008-2009, sford
+ */
+ 
+// VERY DRAFT CODE!!! 
+
+#ifndef SDFILESYSTEM_H
+#define SDFILESYSTEM_H
+
+#include "mbed.h"
+#include "FATFileSystem.h"
+
+/* Class: SDFileSystem
+ *  Access the filesystem on an SD Card using SPI
+ *
+ * Example:
+ * > SDFileSystem sd(p5, p6, p7, p12, "sd");
+ * > 
+ * > int main() {
+ * >     FILE *fp = fopen("/sd/myfile.txt", "w");
+ * >     fprintf(fp, "Hello World!\n");
+ * >     fclose(fp);
+ * > }
+ */
+class SDFileSystem : public FATFileSystem {
+public:
+
+    /* Constructor: SDFileSystem
+     *  Create the File System for accessing an SD Card using SPI
+     *
+     * Variables:
+     *  mosi - SPI mosi pin connected to SD Card
+     *  miso - SPI miso pin conencted to SD Card
+     *  sclk - SPI sclk pin connected to SD Card
+     *  cs   - DigitalOut pin used as SD Card chip select
+   *  name - The name used to access the filesystem
+     */
+    SDFileSystem(PinName mosi, PinName miso, PinName sclk, PinName cs, const char* name);
+    virtual int disk_initialize();
+    virtual int disk_write(const char *buffer, int block_number);
+    virtual int disk_read(char *buffer, int block_number);    
+    virtual int disk_status();
+    virtual int disk_sync();
+    virtual int disk_sectors();
+
+protected:
+
+    int _cmd(int cmd, int arg);
+    int _cmdx(int cmd, int arg);
+    int _cmd8();
+    int _cmd58();
+    int initialise_card();
+    int initialise_card_v1();
+    int initialise_card_v2();
+    
+    
+    int _read(char *buffer, int length);
+    int _write(const char *buffer, int length);
+    int _sd_sectors();
+    int _sectors;
+    
+    SPI _spi;
+    DigitalOut _cs;     
+};
+
+#endif
\ No newline at end of file