Diff: SDFileSystem.cpp

Revision:

6:a1fd0f1374e6

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SDFileSystem.cpp	Mon Apr 30 13:53:09 2018 +0000
@@ -0,0 +1,935 @@
+/* SD/MMC File System Library
+ * Copyright (c) 2016 Neil Thiessen
+ *
+ * Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
+ *
+ * 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 "SDFileSystem.h"
+#include "diskio.h"
+#include "pinmap.h"
+#include "SDCRC.h"
+
+SDFileSystem::SDFileSystem(PinName mosi, PinName miso, PinName sclk, PinName cs, const char* name, PinName cd, SwitchType cdtype, int hz)
+    : FATFileSystem(name),
+      m_Spi(mosi, miso, sclk),
+      m_Cs(cs, 1),
+      m_Cd(cd),
+      m_FREQ(hz)
+{
+    //Initialize the member variables
+    m_CardType = CARD_NONE;
+    m_Crc = true;
+    m_LargeFrames = false;
+    m_WriteValidation = true;
+    m_Status = STA_NOINIT;
+
+    //Enable the internal pull-up resistor on MISO
+    pin_mode(miso, PullUp);
+
+    //Configure the SPI bus
+    m_Spi.format(8, 0);
+
+    //Configure the card detect pin
+    if (cdtype == SWITCH_POS_NO) {
+        m_Cd.mode(PullDown);
+        m_CdAssert = 1;
+        m_Cd.fall(this, &SDFileSystem::onCardRemoval);
+    } else if (cdtype == SWITCH_POS_NC) {
+        m_Cd.mode(PullDown);
+        m_CdAssert = 0;
+        m_Cd.rise(this, &SDFileSystem::onCardRemoval);
+    } else if (cdtype == SWITCH_NEG_NO) {
+        m_Cd.mode(PullUp);
+        m_CdAssert = 0;
+        m_Cd.rise(this, &SDFileSystem::onCardRemoval);
+    } else if (cdtype == SWITCH_NEG_NC) {
+        m_Cd.mode(PullUp);
+        m_CdAssert = 1;
+        m_Cd.fall(this, &SDFileSystem::onCardRemoval);
+    } else {
+        m_CdAssert = -1;
+    }
+}
+
+bool SDFileSystem::card_present()
+{
+    //Check the card socket
+    checkSocket();
+
+    //Return whether or not a card is present
+    return !(m_Status & STA_NODISK);
+}
+
+SDFileSystem::CardType SDFileSystem::card_type()
+{
+    //Check the card socket
+    checkSocket();
+
+    //Return the card type
+    return m_CardType;
+}
+
+bool SDFileSystem::crc()
+{
+    //Return whether or not CRC is enabled
+    return m_Crc;
+}
+
+void SDFileSystem::crc(bool enabled)
+{
+    //Check the card socket
+    checkSocket();
+
+    //Just update the member variable if the card isn't initialized
+    if (m_Status & STA_NOINIT) {
+        m_Crc = enabled;
+        return;
+    }
+
+    //Enable or disable CRC
+    if (enabled && !m_Crc) {
+        //Send CMD59(0x00000001) to enable CRC
+        m_Crc = true;
+        commandTransaction(CMD59, 0x00000001);
+    } else if (!enabled && m_Crc) {
+        //Send CMD59(0x00000000) to disable CRC
+        commandTransaction(CMD59, 0x00000000);
+        m_Crc = false;
+    }
+}
+
+bool SDFileSystem::large_frames()
+{
+    //Return whether or not 16-bit frames are enabled
+    return m_LargeFrames;
+}
+
+void SDFileSystem::large_frames(bool enabled)
+{
+    //Set whether or not 16-bit frames are enabled
+    m_LargeFrames = enabled;
+}
+
+bool SDFileSystem::write_validation()
+{
+    //Return whether or not write validation is enabled
+    return m_WriteValidation;
+}
+
+void SDFileSystem::write_validation(bool enabled)
+{
+    //Set whether or not write validation is enabled
+    m_WriteValidation = enabled;
+}
+
+int SDFileSystem::unmount()
+{
+    //Unmount the filesystem
+    FATFileSystem::unmount();
+
+    //Change the status to not initialized, and the card type to unknown
+    m_Status |= STA_NOINIT;
+    m_CardType = CARD_UNKNOWN;
+
+    //Always succeeds
+    return 0;
+}
+
+int SDFileSystem::disk_initialize()
+{
+    char token;
+    unsigned int resp;
+    Timer timer;
+
+    //Make sure there's a card in the socket before proceeding
+    checkSocket();
+    if (m_Status & STA_NODISK)
+        return m_Status;
+
+    //Make sure we're not already initialized before proceeding
+    if (!(m_Status & STA_NOINIT))
+        return m_Status;
+
+    //Set the SPI frequency to 400kHz for initialization
+    m_Spi.frequency(400000);
+
+    //Try to reset the card up to 3 times
+    for (int f = 0; f < 3; f++) {
+        //Send 80 dummy clocks with /CS deasserted and DI held high
+        m_Cs = 1;
+        for (int i = 0; i < 10; i++) {
+            m_Spi.write(0xFF);
+        }
+
+        //Send CMD0(0x00000000) to reset the card
+        token = commandTransaction(CMD0, 0x00000000);
+        if (token == 0x01) {
+            break;
+        }
+    }
+
+    //Check if the card reset
+    if (token != 0x01) {
+        //Initialization failed
+        m_CardType = CARD_UNKNOWN;
+        return m_Status;
+    }
+
+    //Send CMD59(0x00000001) to enable CRC if necessary
+    if (m_Crc) {
+        if (commandTransaction(CMD59, 0x00000001) != 0x01) {
+            //Initialization failed
+            m_CardType = CARD_UNKNOWN;
+            return m_Status;
+        }
+    }
+
+    //Send CMD8(0x000001AA) to see if this is an SDCv2 card
+    if (commandTransaction(CMD8, 0x000001AA, &resp) == 0x01) {
+        //This is an SDCv2 card, get the 32-bit return value and verify the voltage range/check pattern
+        if ((resp & 0xFFF) != 0x1AA) {
+            //Initialization failed
+            m_CardType = CARD_UNKNOWN;
+            return m_Status;
+        }
+
+        //Send CMD58(0x00000000) to read the OCR, and verify that the card supports 3.2-3.3V
+        if (commandTransaction(CMD58, 0x00000000, &resp) != 0x01 || !(resp & (1 << 20))) {
+            //Initialization failed
+            m_CardType = CARD_UNKNOWN;
+            return m_Status;
+        }
+
+        //Try to initialize the card using ACMD41(0x40100000) for up to 2 seconds
+        timer.start();
+        do {
+            token = commandTransaction(ACMD41, 0x40100000);
+        } while (token == 0x01 && timer.read_ms() < 2000);
+        timer.stop();
+        timer.reset();
+
+        //Check if the card initialized
+        if (token != 0x00) {
+            //Initialization failed
+            m_CardType = CARD_UNKNOWN;
+            return m_Status;
+        }
+
+        //Send CMD58(0x00000000) to read the OCR
+        if (commandTransaction(CMD58, 0x00000000, &resp) == 0x00) {
+            //Check the CCS bit to determine if this is a high capacity card
+            if (resp & (1 << 30))
+                m_CardType = CARD_SDHC;
+            else
+                m_CardType = CARD_SD;
+
+            //Increase the SPI frequency to full speed (up to 50MHz for SDCv2)
+            if (m_FREQ > 25000000) {
+                if (enableHighSpeedMode()) {
+                    if (m_FREQ > 50000000) {
+                        m_Spi.frequency(50000000);
+                    } else {
+                        m_Spi.frequency(m_FREQ);
+                    }
+                } else {
+                    m_Spi.frequency(25000000);
+                }
+            } else {
+                m_Spi.frequency(m_FREQ);
+            }
+        } else {
+            //Initialization failed
+            m_CardType = CARD_UNKNOWN;
+            return m_Status;
+        }
+    } else {
+        //Didn't respond or illegal command, this is either an SDCv1 or MMC card
+        //Send CMD58(0x00000000) to read the OCR, and verify that the card supports 3.2-3.3V
+        if (commandTransaction(CMD58, 0x00000000, &resp) != 0x01 || !(resp & (1 << 20))) {
+            //Initialization failed
+            m_CardType = CARD_UNKNOWN;
+            return m_Status;
+        }
+
+        //Try to initialize the card using ACMD41(0x40100000) for up to 2 seconds
+        timer.start();
+        do {
+            token = commandTransaction(ACMD41, 0x40100000);
+        } while (token == 0x01 && timer.read_ms() < 2000);
+        timer.stop();
+        timer.reset();
+
+        //Check if the card initialized
+        if (token == 0x00) {
+            //This is an SDCv1 standard capacity card
+            m_CardType = CARD_SD;
+
+            //Increase the SPI frequency to full speed (up to 25MHz for SDCv1)
+            if (m_FREQ > 25000000)
+                m_Spi.frequency(25000000);
+            else
+                m_Spi.frequency(m_FREQ);
+        } else {
+            //Try to initialize the card using CMD1(0x00100000) for up to 2 seconds
+            timer.start();
+            do {
+                token = commandTransaction(CMD1, 0x00100000);
+            } while (token == 0x01 && timer.read_ms() < 2000);
+            timer.stop();
+            timer.reset();
+
+            //Check if the card initialized
+            if (token == 0x00) {
+                //This is an MMCv3 card
+                m_CardType = CARD_MMC;
+
+                //Increase the SPI frequency to full speed (up to 20MHz for MMCv3)
+                if (m_FREQ > 20000000)
+                    m_Spi.frequency(20000000);
+                else
+                    m_Spi.frequency(m_FREQ);
+            } else {
+                //Initialization failed
+                m_CardType = CARD_UNKNOWN;
+                return m_Status;
+            }
+        }
+    }
+
+    //Send ACMD42(0x00000000) to disconnect the internal pull-up resistor on pin 1 if necessary
+    if (m_CardType != CARD_MMC) {
+        if (commandTransaction(ACMD42, 0x00000000) != 0x00) {
+            //Initialization failed
+            m_CardType = CARD_UNKNOWN;
+            return m_Status;
+        }
+    }
+
+    //Send CMD16(0x00000200) to force the block size to 512B if necessary
+    if (m_CardType != CARD_SDHC) {
+        if (commandTransaction(CMD16, 0x00000200) != 0x00) {
+            //Initialization failed
+            m_CardType = CARD_UNKNOWN;
+            return m_Status;
+        }
+    }
+
+    //The card is now initialized
+    m_Status &= ~STA_NOINIT;
+
+    //Return the disk status
+    return m_Status;
+}
+
+int SDFileSystem::disk_status()
+{
+    //Check the card socket
+    checkSocket();
+
+    //Return the disk status
+    return m_Status;
+}
+
+int SDFileSystem::disk_read(uint8_t* buffer, uint32_t sector, uint32_t count)
+{
+    //Make sure the card is initialized before proceeding
+    if (m_Status & STA_NOINIT)
+        return RES_NOTRDY;
+
+    //Read a single block, or multiple blocks
+    if (count > 1) {
+        return readBlocks((char*)buffer, sector, count) ? RES_OK : RES_ERROR;
+    } else {
+        return readBlock((char*)buffer, sector) ? RES_OK : RES_ERROR;
+    }
+}
+
+int SDFileSystem::disk_write(const uint8_t* buffer, uint32_t sector, uint32_t count)
+{
+    //Make sure the card is initialized before proceeding
+    if (m_Status & STA_NOINIT)
+        return RES_NOTRDY;
+
+    //Make sure the card isn't write protected before proceeding
+    if (m_Status & STA_PROTECT)
+        return RES_WRPRT;
+
+    //Write a single block, or multiple blocks
+    if (count > 1) {
+        return writeBlocks((const char*)buffer, sector, count) ? RES_OK : RES_ERROR;
+    } else {
+        return writeBlock((const char*)buffer, sector) ? RES_OK : RES_ERROR;
+    }
+}
+
+int SDFileSystem::disk_sync()
+{
+    //Select the card so we're forced to wait for the end of any internal write processes
+    if (select()) {
+        deselect();
+        return RES_OK;
+    } else {
+        return RES_ERROR;
+    }
+}
+
+uint32_t SDFileSystem::disk_sectors()
+{
+    //Make sure the card is initialized before proceeding
+    if (m_Status & STA_NOINIT)
+        return 0;
+
+    //Try to read the CSD register up to 3 times
+    for (int f = 0; f < 3; f++) {
+        //Select the card, and wait for ready
+        if(!select())
+            break;
+
+        //Send CMD9(0x00000000) to read the CSD register
+        if (writeCommand(CMD9, 0x00000000) == 0x00) {
+            //Read the 16B CSD data block
+            char csd[16];
+            bool success = readData(csd, 16);
+            deselect();
+            if (success) {
+                //Calculate the sector count based on the card type
+                if ((csd[0] >> 6) == 0x01) {
+                    //Calculate the sector count for a high capacity card
+                    unsigned int size = (((csd[7] & 0x3F) << 16) | (csd[8] << 8) | csd[9]) + 1;
+                    return size << 10;
+                } else {
+                    //Calculate the sector count for a standard capacity card
+                    unsigned int size = (((csd[6] & 0x03) << 10) | (csd[7] << 2) | ((csd[8] & 0xC0) >> 6)) + 1;
+                    size <<= ((((csd[9] & 0x03) << 1) | ((csd[10] & 0x80) >> 7)) + 2);
+                    size <<= (csd[5] & 0x0F);
+                    return size >> 9;
+                }
+            }
+        } else {
+            //The command failed, get out
+            break;
+        }
+    }
+
+    //The read operation failed 3 times
+    deselect();
+    return 0;
+}
+
+void SDFileSystem::onCardRemoval()
+{
+    //Check the card socket
+    checkSocket();
+}
+
+inline void SDFileSystem::checkSocket()
+{
+    //Use the card detect switch (if available) to determine if the socket is occupied
+    if (m_CdAssert != -1) {
+        if (m_Status & STA_NODISK) {
+            if (m_Cd == m_CdAssert) {
+                //The socket is now occupied
+                m_Status &= ~STA_NODISK;
+                m_CardType = CARD_UNKNOWN;
+            }
+        } else {
+            if (m_Cd != m_CdAssert) {
+                //The socket is now empty
+                m_Status |= (STA_NODISK | STA_NOINIT);
+                m_CardType = CARD_NONE;
+            }
+        }
+    }
+}
+
+inline bool SDFileSystem::waitReady(int timeout)
+{
+    char resp;
+
+    //Keep sending dummy clocks with DI held high until the card releases the DO line
+    m_Timer.start();
+    do {
+        resp = m_Spi.write(0xFF);
+    } while (resp == 0x00 && m_Timer.read_ms() < timeout);
+    m_Timer.stop();
+    m_Timer.reset();
+
+    //Return success/failure
+    return (resp > 0x00);
+}
+
+inline bool SDFileSystem::select()
+{
+    //Assert /CS
+    m_Cs = 0;
+
+    //Send 8 dummy clocks with DI held high to enable DO
+    m_Spi.write(0xFF);
+
+    //Wait for up to 500ms for the card to become ready
+    if (waitReady(500)) {
+        return true;
+    } else {
+        //We timed out, deselect and return false
+        deselect();
+        return false;
+    }
+}
+
+inline void SDFileSystem::deselect()
+{
+    //Deassert /CS
+    m_Cs = 1;
+
+    //Send 8 dummy clocks with DI held high to disable DO
+    m_Spi.write(0xFF);
+}
+
+inline char SDFileSystem::commandTransaction(char cmd, unsigned int arg, unsigned int* resp)
+{
+    //Select the card, and wait for ready
+    if(!select())
+        return 0xFF;
+
+    //Perform the command transaction
+    char token = writeCommand(cmd, arg, resp);
+
+    //Deselect the card, and return the R1 response token
+    deselect();
+    return token;
+}
+
+char SDFileSystem::writeCommand(char cmd, unsigned int arg, unsigned int* resp)
+{
+    char token;
+
+    //Try to send the command up to 3 times
+    for (int f = 0; f < 3; f++) {
+        //Send CMD55(0x00000000) prior to an application specific command
+        if (cmd == ACMD22 || cmd == ACMD23 || cmd == ACMD41 || cmd == ACMD42) {
+            token = writeCommand(CMD55, 0x00000000);
+            if (token > 0x01)
+                return token;
+
+            //Deselect and reselect the card between CMD55 and an ACMD
+            deselect();
+            if(!select())
+                return 0xFF;
+        }
+
+        //Prepare the command packet
+        char cmdPacket[6];
+        cmdPacket[0] = cmd;
+        cmdPacket[1] = arg >> 24;
+        cmdPacket[2] = arg >> 16;
+        cmdPacket[3] = arg >> 8;
+        cmdPacket[4] = arg;
+        if (m_Crc || cmd == CMD0 || cmd == CMD8)
+            cmdPacket[5] = (SDCRC::crc7(cmdPacket, 5) << 1) | 0x01;
+        else
+            cmdPacket[5] = 0x01;
+
+        //Send the command packet
+        for (int i = 0; i < 6; i++)
+            m_Spi.write(cmdPacket[i]);
+
+        //Discard the stuff byte immediately following CMD12
+        if (cmd == CMD12)
+            m_Spi.write(0xFF);
+
+        //Allow up to 8 bytes of delay for the R1 response token
+        for (int i = 0; i < 9; i++) {
+            token = m_Spi.write(0xFF);
+            if (!(token & 0x80))
+                break;
+        }
+
+        //Verify the R1 response token
+        if (token == 0xFF) {
+            //No data was received, get out early
+            break;
+        } else if (token & (1 << 3)) {
+            //There was a CRC error, try again
+            continue;
+        } else if (token > 0x01) {
+            //An error occured, get out early
+            break;
+        }
+
+        //Handle R2 and R3/R7 response tokens
+        if (cmd == CMD13 && resp != NULL) {
+            //Read the R2 response value
+            *resp = m_Spi.write(0xFF);
+        } else if ((cmd == CMD8 || cmd == CMD58) && resp != NULL) {
+            //Read the R3/R7 response value
+            *resp = (m_Spi.write(0xFF) << 24);
+            *resp |= (m_Spi.write(0xFF) << 16);
+            *resp |= (m_Spi.write(0xFF) << 8);
+            *resp |= m_Spi.write(0xFF);
+        }
+
+        //The command was successful
+        break;
+    }
+
+    //Return the R1 response token
+    return token;
+}
+
+bool SDFileSystem::readData(char* buffer, int length)
+{
+    char token;
+    unsigned short crc;
+
+    //Wait for up to 500ms for a token to arrive
+    m_Timer.start();
+    do {
+        token = m_Spi.write(0xFF);
+    } while (token == 0xFF && m_Timer.read_ms() < 500);
+    m_Timer.stop();
+    m_Timer.reset();
+
+    //Check if a valid start block token was received
+    if (token != 0xFE)
+        return false;
+
+    //Check if large frames are enabled or not
+    if (m_LargeFrames) {
+        //Switch to 16-bit frames for better performance
+        m_Spi.format(16, 0);
+
+        //Read the data block into the buffer
+        unsigned short dataWord;
+        for (int i = 0; i < length; i += 2) {
+            dataWord = m_Spi.write(0xFFFF);
+            buffer[i] = dataWord >> 8;
+            buffer[i + 1] = dataWord;
+        }
+
+        //Read the CRC16 checksum for the data block
+        crc = m_Spi.write(0xFFFF);
+
+        //Switch back to 8-bit frames
+        m_Spi.format(8, 0);
+    } else {
+        //Read the data into the buffer
+        for (int i = 0; i < length; i++)
+            buffer[i] = m_Spi.write(0xFF);
+
+        //Read the CRC16 checksum for the data block
+        crc = (m_Spi.write(0xFF) << 8);
+        crc |= m_Spi.write(0xFF);
+    }
+
+    //Return the validity of the CRC16 checksum (if enabled)
+    return (!m_Crc || crc == SDCRC::crc16(buffer, length));
+}
+
+char SDFileSystem::writeData(const char* buffer, char token)
+{
+    //Calculate the CRC16 checksum for the data block (if enabled)
+    unsigned short crc = (m_Crc) ? SDCRC::crc16(buffer, 512) : 0xFFFF;
+
+    //Wait for up to 500ms for the card to become ready
+    if (!waitReady(500))
+        return false;
+
+    //Send the start block token
+    m_Spi.write(token);
+
+    //Check if large frames are enabled or not
+    if (m_LargeFrames) {
+        //Switch to 16-bit frames for better performance
+        m_Spi.format(16, 0);
+
+        //Write the data block from the buffer
+        for (int i = 0; i < 512; i += 2)
+            m_Spi.write((buffer[i] << 8) | buffer[i + 1]);
+
+        //Send the CRC16 checksum for the data block
+        m_Spi.write(crc);
+
+        //Switch back to 8-bit frames
+        m_Spi.format(8, 0);
+    } else {
+        //Write the data block from the buffer
+        for (int i = 0; i < 512; i++)
+            m_Spi.write(buffer[i]);
+
+        //Send the CRC16 checksum for the data block
+        m_Spi.write(crc >> 8);
+        m_Spi.write(crc);
+    }
+
+    //Return the data response token
+    return (m_Spi.write(0xFF) & 0x1F);
+}
+
+inline bool SDFileSystem::readBlock(char* buffer, unsigned int lba)
+{
+    //Try to read the block up to 3 times
+    for (int f = 0; f < 3; f++) {
+        //Select the card, and wait for ready
+        if(!select())
+            break;
+
+        //Send CMD17(block) to read a single block
+        if (writeCommand(CMD17, (m_CardType == CARD_SDHC) ? lba : lba << 9) == 0x00) {
+            //Try to read the block, and deselect the card
+            bool success = readData(buffer, 512);
+            deselect();
+
+            //Return if successful
+            if (success)
+                return true;
+        } else {
+            //The command failed, get out
+            break;
+        }
+    }
+
+    //The single block read failed
+    deselect();
+    return false;
+}
+
+inline bool SDFileSystem::readBlocks(char* buffer, unsigned int lba, unsigned int count)
+{
+    //Try to read each block up to 3 times
+    for (int f = 0; f < 3;) {
+        //Select the card, and wait for ready
+        if(!select())
+            break;
+
+        //Send CMD18(block) to read multiple blocks
+        if (writeCommand(CMD18, (m_CardType == CARD_SDHC) ? lba : lba << 9) == 0x00) {
+            //Try to read all of the data blocks
+            do {
+                //Read the next block, and break on errors
+                if (!readData(buffer, 512)) {
+                    f++;
+                    break;
+                }
+
+                //Update the variables
+                lba++;
+                buffer += 512;
+                f = 0;
+            } while (--count);
+
+            //Send CMD12(0x00000000) to stop the transmission
+            if (writeCommand(CMD12, 0x00000000) != 0x00) {
+                //The command failed, get out
+                break;
+            }
+
+            //Deselect the card, and return if successful
+            deselect();
+            if (count == 0)
+                return true;
+        } else {
+            //The command failed, get out
+            break;
+        }
+    }
+
+    //The multiple block read failed
+    deselect();
+    return false;
+}
+
+inline bool SDFileSystem::writeBlock(const char* buffer, unsigned int lba)
+{
+    //Try to write the block up to 3 times
+    for (int f = 0; f < 3; f++) {
+        //Select the card, and wait for ready
+        if(!select())
+            break;
+
+        //Send CMD24(block) to write a single block
+        if (writeCommand(CMD24, (m_CardType == CARD_SDHC) ? lba : lba << 9) == 0x00) {
+            //Try to write the block, and deselect the card
+            char token = writeData(buffer, 0xFE);
+            deselect();
+
+            //Check the data response token
+            if (token == 0x0A) {
+                //A CRC error occured, try again
+                continue;
+            } else if (token == 0x0C) {
+                //A write error occured, get out
+                break;
+            }
+
+            //Send CMD13(0x00000000) to verify that the programming was successful if enabled
+            if (m_WriteValidation) {
+                unsigned int resp;
+                if (commandTransaction(CMD13, 0x00000000, &resp) != 0x00 || resp != 0x00) {
+                    //Some manner of unrecoverable write error occured during programming, get out
+                    break;
+                }
+            }
+
+            //The data was written successfully
+            return true;
+        } else {
+            //The command failed, get out
+            break;
+        }
+    }
+
+    //The single block write failed
+    deselect();
+    return false;
+}
+
+inline bool SDFileSystem::writeBlocks(const char* buffer, unsigned int lba, unsigned int count)
+{
+    char token;
+    const char* currentBuffer = buffer;
+    unsigned int currentLba = lba;
+    int currentCount = count;
+
+    //Try to write each block up to 3 times
+    for (int f = 0; f < 3;) {
+        //If this is an SD card, send ACMD23(count) to set the number of blocks to pre-erase
+        if (m_CardType != CARD_MMC) {
+            if (commandTransaction(ACMD23, currentCount) != 0x00) {
+                //The command failed, get out
+                break;
+            }
+        }
+
+        //Select the card, and wait for ready
+        if(!select())
+            break;
+
+        //Send CMD25(block) to write multiple blocks
+        if (writeCommand(CMD25, (m_CardType == CARD_SDHC) ? currentLba : currentLba << 9) == 0x00) {
+            //Try to write all of the data blocks
+            do {
+                //Write the next block and break on errors
+                token = writeData(currentBuffer, 0xFC);
+                if (token != 0x05) {
+                    f++;
+                    break;
+                }
+
+                //Update the variables
+                currentBuffer += 512;
+                f = 0;
+            } while (--currentCount);
+
+            //Wait for up to 500ms for the card to finish processing the last block
+            if (!waitReady(500))
+                break;
+
+            //Finalize the transmission
+            if (currentCount == 0) {
+                //Send the stop tran token, and deselect the card
+                m_Spi.write(0xFD);
+                deselect();
+
+                //Send CMD13(0x00000000) to verify that the programming was successful if enabled
+                if (m_WriteValidation) {
+                    unsigned int resp;
+                    if (commandTransaction(CMD13, 0x00000000, &resp) != 0x00 || resp != 0x00) {
+                        //Some manner of unrecoverable write error occured during programming, get out
+                        break;
+                    }
+                }
+
+                //The data was written successfully
+                return true;
+            } else {
+                //Send CMD12(0x00000000) to abort the transmission
+                if (writeCommand(CMD12, 0x00000000) != 0x00) {
+                    //The command failed, get out
+                    break;
+                }
+
+                //Deselect the card
+                deselect();
+
+                //Check the error token
+                if (token == 0x0A) {
+                    //Determine the number of well written blocks if possible
+                    unsigned int writtenBlocks = 0;
+                    if (m_CardType != CARD_MMC && select()) {
+                        //Send ACMD22(0x00000000) to get the number of well written blocks
+                        if (writeCommand(ACMD22, 0x00000000) == 0x00) {
+                            //Read the data
+                            char acmdData[4];
+                            if (readData(acmdData, 4)) {
+                                //Extract the number of well written blocks
+                                writtenBlocks = acmdData[0] << 24;
+                                writtenBlocks |= acmdData[1] << 16;
+                                writtenBlocks |= acmdData[2] << 8;
+                                writtenBlocks |= acmdData[3];
+                            }
+                        }
+                        deselect();
+                    }
+
+                    //Roll back the variables based on the number of well written blocks
+                    currentBuffer = buffer + (writtenBlocks << 9);
+                    currentLba = lba + writtenBlocks;
+                    currentCount = count - writtenBlocks;
+
+                    //Try again
+                    continue;
+                } else {
+                    //A write error occured, get out
+                    break;
+                }
+            }
+        } else {
+            //The command failed, get out
+            break;
+        }
+    }
+
+    //The multiple block write failed
+    deselect();
+    return false;
+}
+
+bool SDFileSystem::enableHighSpeedMode()
+{
+    //Try to issue CMD6 up to 3 times
+    for (int f = 0; f < 3; f++) {
+        //Select the card, and wait for ready
+        if(!select())
+            break;
+
+        //Send CMD6(0x80FFFFF1) to change the access mode to high speed
+        if (writeCommand(CMD6, 0x80FFFFF1) == 0x00) {
+            //Read the 64B status data block
+            char status[64];
+            bool success = readData(status, 64);
+            deselect();
+            if (success) {
+                //Return whether or not the operation was successful
+                return ((status[16] & 0x0F) == 0x1);
+            }
+        } else {
+            //The command failed, get out
+            break;
+        }
+    }
+
+    //The operation failed 3 times
+    deselect();
+    return false;
+}
+