Added SCSD support. Fixed a few FAT errors.

source/disc_io/disc.c

@@ -87,9 +87,9 @@ IO_INTERFACE* ioInterfaces[] = {
 	&_io_nmmc,
 #endif
 	// Place Slot 2 (GBA Cart) interfaces here
-	&_io_mpcf, &_io_m3cf, &_io_m3sd, &_io_sccf, &_io_fcsr
+	&_io_mpcf, &_io_m3cf, &_io_sccf, &_io_scsd, &_io_m3sd, &_io_fcsr
 	// Experimental Slot 2 interfaces
-	, &_io_mmcf, &_io_scsd, &_io_efa2
+	, &_io_mmcf, &_io_efa2
 };
 
 /*

source/disc_io/io_m3sd.c

@@ -47,14 +47,14 @@
 
 //---------------------------------------------------------------
 // Send / receive timeouts, to stop infinite wait loops
-#define MAX_STARTUP_TRIES 100	// Arbitrary value, check if the card is ready 100 times before giving up
+#define MAX_STARTUP_TRIES 10	// Arbitrary value, check if the card is ready 10 times before giving up
 #define NUM_STARTUP_CLOCKS 100	// Number of empty (0xFF when sending) bytes to send/receive to/from the card
-#define TRANSMIT_TIMEOUT 0x100	// Time to wait for the M3 to respond to transmit or receive requests
+#define TRANSMIT_TIMEOUT 2000	// Time to wait for the M3 to respond to transmit or receive requests
 #define RESPONSE_TIMEOUT 256	// Number of clocks sent to the SD card before giving up
 
 //---------------------------------------------------------------
 // Variables required for tracking SD state
-static u32 relativeCardAddress = 0;	// Preshifted Relative Card Address
+static u32 _M3SD_relativeCardAddress = 0;	// Preshifted Relative Card Address
 
 //---------------------------------------------------------------
 // Internal M3 SD functions
@@ -241,7 +241,7 @@ static bool _M3SD_initCard (void) {
 	_M3SD_getClocks (NUM_STARTUP_CLOCKS);
 
 	// Card is now reset, including it's address
-	relativeCardAddress = 0;
+	_M3SD_relativeCardAddress = 0;
 
 	for (i = 0; i < MAX_STARTUP_TRIES ; i++) {
 		_M3SD_sendCommand (APP_CMD, 0);
@@ -265,18 +265,18 @@ static bool _M3SD_initCard (void) {
 	// Get a new address
 	_M3SD_sendCommand (SEND_RELATIVE_ADDR, 0);
 	_M3SD_getResponse_R6 (responseBuffer);
-	relativeCardAddress = (responseBuffer[1] << 24) | (responseBuffer[2] << 16);
+	_M3SD_relativeCardAddress = (responseBuffer[1] << 24) | (responseBuffer[2] << 16);
 	
 	// Some cards won't go to higher speeds unless they think you checked their capabilities
-	_M3SD_sendCommand (SEND_CSD, relativeCardAddress);
+	_M3SD_sendCommand (SEND_CSD, _M3SD_relativeCardAddress);
 	_M3SD_getResponse_R2 (responseBuffer);
 	
 	// Only this card should respond to all future commands
-	_M3SD_sendCommand (SELECT_CARD, relativeCardAddress);
+	_M3SD_sendCommand (SELECT_CARD, _M3SD_relativeCardAddress);
 	_M3SD_getResponse_R1 (responseBuffer);
 	
 	// Set a 4 bit data bus
-	_M3SD_sendCommand (APP_CMD, relativeCardAddress);
+	_M3SD_sendCommand (APP_CMD, _M3SD_relativeCardAddress);
 	_M3SD_getResponse_R1 (responseBuffer);
 	
 	_M3SD_sendCommand (SET_BUS_WIDTH, 2);
@@ -293,9 +293,8 @@ static bool _M3SD_initCard (void) {
 			return false;
 		}
 		i++;
-		_M3SD_sendCommand (SEND_STATUS, relativeCardAddress);
+		_M3SD_sendCommand (SEND_STATUS, _M3SD_relativeCardAddress);
 	} while ((!_M3SD_getResponse_R1 (responseBuffer)) && ((responseBuffer[3] & 0x1f) != ((SD_STATE_TRAN << 1) | READY_FOR_DATA)));
-	
 	return true;
 }
 

source/disc_io/io_mmcf.c

@@ -62,7 +62,7 @@
 #define REG_MMCF_LBA3		((vu16*)0x080A0000)	// 3rd byte of sector address
 #define REG_MMCF_LBA4		((vu16*)0x080C0000)	// last nibble of sector address | 0xE0
 
-#define REG_MMCF_DATA		((vu16*)0x09000000)		// Pointer to buffer of CF data transered from card
+#define REG_MMCF_DATA		((vu16*)0x08000000)		// Pointer to buffer of CF data transered from card
 
 static const CF_REGISTERS _MMCF_Registers = {
 	REG_MMCF_DATA,

source/disc_io/io_nmmc.c

@@ -25,7 +25,7 @@
 
 #include <nds/card.h>
 
-int spi_freq = 3;
+int _NMMC_spi_freq = 3;
 
 #define MK2_CONFIG_ZIP_RAM_CLOSE		(1 << 5)
 #define MK2_CONFIG_GAME_FLASH_CLOSE		((1 << 4) | (1 << 0))
@@ -61,13 +61,13 @@ static inline void _Neo_CloseSPI ( void )
 }
 
 static inline void _Neo_MK2GameMode()	{
-	_Neo_OpenSPI(spi_freq);				// Enable DS Card's SPI port
+	_Neo_OpenSPI(_NMMC_spi_freq);				// Enable DS Card's SPI port
 	_Neo_SPI(0xF1);				// Switch to game mode
 	_Neo_CloseSPI();				// Disable DS Card's SPI port
 }
 
 static inline void _Neo_EnableEEPROM( bool enable )	{
-	_Neo_OpenSPI(spi_freq);
+	_Neo_OpenSPI(_NMMC_spi_freq);
 	if(enable)	_Neo_SPI(0x06);
 	else 		_Neo_SPI(0x0E);
 	_Neo_CloseSPI();
@@ -75,7 +75,7 @@ static inline void _Neo_EnableEEPROM( bool enable )	{
 
 static void _Neo_WriteMK2Config(u8 config) {
 	_Neo_EnableEEPROM(true);
-	_Neo_OpenSPI(spi_freq);
+	_Neo_OpenSPI(_NMMC_spi_freq);
 	_Neo_SPI(0xFA);					// Send mem conf write command
 	_Neo_SPI(0x01);					// Send high byte (0x01)
 	_Neo_SPI(config);				// Send low byte
@@ -87,7 +87,7 @@ static u8 _Neo_ReadMK2Config(void)
 {
 	u8 config;
 	_Neo_EnableEEPROM(true);
-	_Neo_OpenSPI(spi_freq);
+	_Neo_OpenSPI(_NMMC_spi_freq);
 	_Neo_SPI(0xf8);					// Send mem conf read command
 	_Neo_SPI(0x01);					// Send high byte
 	config = _Neo_SPI(0x00);			// Get low byte
@@ -118,7 +118,7 @@ static void _Neo_EnableMMC( bool enable )
 	} else {
 		_Neo_SelectMMC (1);
 		_Neo_SelectMMC (1);
-		_Neo_OpenSPI (spi_freq);
+		_Neo_OpenSPI (_NMMC_spi_freq);
 	}
 	return;
 }
@@ -246,7 +246,7 @@ bool _NMMC_startUp(void) {
 		_Neo_SPI(0xFF);
 	}
 	if ((transSpeed & 0xf0) >= 0x30) {
-		spi_freq = 0;
+		_NMMC_spi_freq = 0;
 	}
 	
 	_Neo_EnableMMC( false );

source/disc_io/io_scsd.c

@@ -29,6 +29,9 @@
  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
  EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ 
+	2006-07-22 - Chishm
+		* First release of stable code
 */
 
 #include "io_scsd.h"
@@ -58,15 +61,18 @@
 // Send / receive timeouts, to stop infinite wait loops
 #define MAX_STARTUP_TRIES 100	// Arbitrary value, check if the card is ready 100 times before giving up
 #define NUM_STARTUP_CLOCKS 100	// Number of empty (0xFF when sending) bytes to send/receive to/from the card
-#define TRANSMIT_TIMEOUT 0x100	// Time to wait for the M3 to respond to transmit or receive requests
+#define TRANSMIT_TIMEOUT 10000	// Time to wait for the SC to respond to transmit or receive requests
 #define RESPONSE_TIMEOUT 256	// Number of clocks sent to the SD card before giving up
 #define BUSY_WAIT_TIMEOUT 500000
+#define WRITE_TIMEOUT	10000	// Time to wait for the card to finish writing
 //---------------------------------------------------------------
 // Variables required for tracking SD state
-static u32 relativeCardAddress = 0;	// Preshifted Relative Card Address
+static u32 _SCSD_relativeCardAddress = 0;	// Preshifted Relative Card Address
 
 //---------------------------------------------------------------
-// Internal M3 SD functions
+// Internal SC SD functions
+
+extern bool _SCSD_writeData_s (u8 *data, u16* crc);
 
 static inline void _SCSD_unlock (void) {
 	_SC_changeMode (SC_MODE_MEDIA);	
@@ -97,81 +103,57 @@ static bool _SCSD_sendCommand (u8 command, u32 argument) {
 
 	tempDataPtr = databuff;
 	
-	do {
+	while (length--) {
 		dataByte = *tempDataPtr++;
 		for (curBit = 7; curBit >=0; curBit--){
 			REG_SCSD_CMD = dataByte;
 			dataByte = dataByte << 1;
 		}
-	} while (length--);
-	
-	return true;
-}
-
-static u8 _SCSD_getByte (void) {
-	// With every 16 bit read to REG_SCSD_CMD, read a single bit.
-	u32 res = 0;
-	int i;
-	
-	for (i = 1; i < 8; i++) {
-		res = (res << 1) | REG_SCSD_CMD;
 	}
 	
-	return (u8)res;
+	return true;
 }
 
 // Returns the response from the SD card to a previous command.
 static bool _SCSD_getResponse (u8* dest, u32 length) {
 	u32 i;	
-	u8 dataByte;
+	int dataByte;
-	int shiftAmount;
+	int numBits = length * 8;
 	
 	// Wait for the card to be non-busy
-	for (i = 0; i < RESPONSE_TIMEOUT; i++) {
+	i = BUSY_WAIT_TIMEOUT;
-		dataByte = _SCSD_getByte();
+	while (((REG_SCSD_CMD & 0x01) != 0) && (--i));
-		if (dataByte != SD_CARD_BUSY) {
-			break;
-		}
-	}
-	
 	if (dest == NULL) {
 		return true;
 	}
 	
-	// Still busy after the timeout has passed
+	if (i == 0) {
-	if (dataByte == 0xff) {
+		// Still busy after the timeout has passed
 		return false;
 	}
 	
-	// Read response into buffer
+	// The first bit is always 0
-	for ( i = 0; i < length; i++) {
+	dataByte = 0;	
-		dest[i] = dataByte;
+	numBits--;
-		dataByte = _SCSD_getByte();
+	// Read the remaining bits in the response.
-	}
+	// It's always most significant bit first
-	// dataByte will contain the last piece of the response
+	while (numBits--) {
-
+		dataByte = (dataByte << 1) | (REG_SCSD_CMD & 0x01);
-	// Send 16 more clocks, 8 more than the delay required between a response and the next command
+		if ((numBits & 0x7) == 0) {
-	i = _SCSD_getByte();
+			// It's read a whole byte, so store it
-	i = _SCSD_getByte();
+			*dest++ = (u8)dataByte;
-	
+			dataByte = 0;
-	// Shift response so that the bytes are correctly aligned
-	// The register may not contain properly aligned data
-	for (shiftAmount = 0; ((dest[0] << shiftAmount) & 0x80) != 0x00; shiftAmount++) {
-		if (shiftAmount >= 7) {
-			return false;
 		}
 	}
 
-	for (i = 0; i < length - 1; i++) {
+	// Send 16 more clocks, 8 more than the delay required between a response and the next command
-		dest[i] = (dest[i] << shiftAmount) | (dest[i+1] >> (8-shiftAmount));
+	for (i = 0; i < 16; i++) {
+		dataByte = REG_SCSD_CMD;
 	}
-	// Get the last piece of the response from dataByte
-	dest[i] = (dest[i] << shiftAmount) | (dataByte >> (8-shiftAmount));
 	
 	return true;
 }
 
-
 static inline bool _SCSD_getResponse_R1 (u8* dest) {
 	return _SCSD_getResponse (dest, 6);
 }
@@ -200,23 +182,21 @@ static void _SCSD_sendClocks (u32 numClocks) {
 }
 
 static bool _SCSD_initCard (void) {
-//iprintf ("init card\n");
 	int i;
-	u8 responseBuffer[17];		// sizeof 17 to hold the maximum response size possible
+	u8 responseBuffer[17] = {0};		// sizeof 17 to hold the maximum response size possible
 	
 	// Give the card time to stabilise
 	_SCSD_sendClocks (NUM_STARTUP_CLOCKS);
 	
 	// Reset the card
 	if (!_SCSD_sendCommand (GO_IDLE_STATE, 0)) {
-//iprintf ("can't idle\n");
 		return false;
 	}
 
 	_SCSD_sendClocks (NUM_STARTUP_CLOCKS);
 	
 	// Card is now reset, including it's address
-	relativeCardAddress = 0;
+	_SCSD_relativeCardAddress = 0;
 
 	for (i = 0; i < MAX_STARTUP_TRIES ; i++) {
 		_SCSD_sendCommand (APP_CMD, 0);
@@ -230,7 +210,6 @@ static bool _SCSD_initCard (void) {
 	}
 	
 	if (i >= MAX_STARTUP_TRIES) {
-//iprintf ("timeout on OP_COND\n");
 		return false;
 	}
 
@@ -241,19 +220,18 @@ static bool _SCSD_initCard (void) {
 	// Get a new address
 	_SCSD_sendCommand (SEND_RELATIVE_ADDR, 0);
 	_SCSD_getResponse_R6 (responseBuffer);
-	relativeCardAddress = (responseBuffer[1] << 24) | (responseBuffer[2] << 16);
+	_SCSD_relativeCardAddress = (responseBuffer[1] << 24) | (responseBuffer[2] << 16);
-//iprintf ("Relative Address: %08X\n", relativeCardAddress);
 	
 	// Some cards won't go to higher speeds unless they think you checked their capabilities
-	_SCSD_sendCommand (SEND_CSD, relativeCardAddress);
+	_SCSD_sendCommand (SEND_CSD, _SCSD_relativeCardAddress);
 	_SCSD_getResponse_R2 (responseBuffer);
 	
 	// Only this card should respond to all future commands
-	_SCSD_sendCommand (SELECT_CARD, relativeCardAddress);
+	_SCSD_sendCommand (SELECT_CARD, _SCSD_relativeCardAddress);
 	_SCSD_getResponse_R1 (responseBuffer);
 	
 	// Set a 4 bit data bus
-	_SCSD_sendCommand (APP_CMD, relativeCardAddress);
+	_SCSD_sendCommand (APP_CMD, _SCSD_relativeCardAddress);
 	_SCSD_getResponse_R1 (responseBuffer);
 	
 	_SCSD_sendCommand (SET_BUS_WIDTH, 2);
@@ -267,11 +245,10 @@ static bool _SCSD_initCard (void) {
 	i = 0;
 	do {
 		if (i >= RESPONSE_TIMEOUT) {
-//iprintf ("timeout on SEND_STATUS\n");
 			return false;
 		}
 		i++;
-		_SCSD_sendCommand (SEND_STATUS, relativeCardAddress);
+		_SCSD_sendCommand (SEND_STATUS, _SCSD_relativeCardAddress);
 	} while ((!_SCSD_getResponse_R1 (responseBuffer)) && ((responseBuffer[3] & 0x1f) != ((SD_STATE_TRAN << 1) | READY_FOR_DATA)));
 	
 	return true;
@@ -280,7 +257,7 @@ static bool _SCSD_initCard (void) {
 static bool _SCSD_readData (void* buffer) {
 	u8* buff_u8 = (u8*)buffer;
 	u16* buff = (u16*)buffer;
-	u32 temp;
+	volatile register u32 temp;
 	int i;
 	
 	i = BUSY_WAIT_TIMEOUT;
@@ -291,18 +268,18 @@ static bool _SCSD_readData (void* buffer) {
 
 	i=256;
 	if ((u32)buff_u8 & 0x01) {
-		while(i--)
+		while(i--) {
-		{
 			temp = REG_SCSD_DATAREAD_32;
 			temp = REG_SCSD_DATAREAD_32 >> 16;
 			*buff_u8++ = (u8)temp;
 			*buff_u8++ = (u8)(temp >> 8);
 		}
 	} else {
-		while(i--)
+		while(i--) {
 			temp = REG_SCSD_DATAREAD_32;
 			temp = REG_SCSD_DATAREAD_32 >> 16;
-			*buff++ = (u16)temp; 
+			*buff++ = temp; 
+		}
 	}
 
 	
@@ -315,52 +292,6 @@ static bool _SCSD_readData (void* buffer) {
 	return true;
 }
 
-static bool _SCSD_writeData (u8* data, u8* crc) {
-	int pos;
-	u16 dataHWord;
-	u16 temp;
-	
-	while ((REG_SCSD_DATAREAD & SCSD_STS_BUSY) == 0);
-		
-	temp = REG_SCSD_DATAREAD;
-	
-	REG_SCSD_DATAWRITE = 0;		// start bit;
-		
-	pos = BYTES_PER_READ / 2;
-	while (pos--) {
-		dataHWord = data[0] | (data[1] << 8);
-		data+=2;
-		
-		REG_SCSD_DATAWRITE = dataHWord;
-		REG_SCSD_DATAWRITE = dataHWord << 4;
-		REG_SCSD_DATAWRITE = dataHWord << 8;
-		REG_SCSD_DATAWRITE = dataHWord << 12;
-	}
-	
-	if (crc != 0) {
-		pos = 4;
-		while (pos--) {
-			dataHWord = *crc++;
-			
-			REG_SCSD_DATAWRITE = dataHWord;
-			REG_SCSD_DATAWRITE = dataHWord << 4;
-			REG_SCSD_DATAWRITE = dataHWord << 8;
-			REG_SCSD_DATAWRITE = dataHWord << 12;
-		}
-	}
-	
-	REG_SCSD_DATAWRITE = 0xff;		// end bit
-	
-	while ((REG_SCSD_DATAREAD & SCSD_STS_BUSY) == 0);
-
-	temp = REG_SCSD_DATAREAD;
-	temp = REG_SCSD_DATAREAD;
-	temp = REG_SCSD_DATAREAD;
-	temp = REG_SCSD_DATAREAD;
-
-	return true;
-}
-
 //---------------------------------------------------------------
 // Functions needed for the external interface
 
@@ -423,13 +354,16 @@ bool _SCSD_readSectors (u32 sector, u32 numSectors, void* buffer) {
 }
 
 bool _SCSD_writeSectors (u32 sector, u32 numSectors, const void* buffer) {
-	u16 crcBuff[4];
+	u16 crc[4];	// One per data line
-	u8* crc = (u8*)crcBuff;	// Force crcBuff to be halfword aligned
 	u8 responseBuffer[6];
 	u32 offset = sector * BYTES_PER_READ;
 	u8* data = (u8*) buffer;
+	int i;
 
 	while (numSectors--) {
+		// Calculate the CRC16
+		_SD_CRC16 ( data, BYTES_PER_READ, (u8*)crc);
+		
 		// Send write command and get a response
 		_SCSD_sendCommand (WRITE_BLOCK, offset);
 		if (!_SCSD_getResponse_R1 (responseBuffer)) {
@@ -437,8 +371,7 @@ bool _SCSD_writeSectors (u32 sector, u32 numSectors, const void* buffer) {
 		}
 
 		// Send the data and CRC
-		_SD_CRC16 ( data, BYTES_PER_READ, crc);
+		if (! _SCSD_writeData_s (data, crc)) {
-		if (! _SCSD_writeData( data, crc)) {
 			return false;
 		}
 			
@@ -447,10 +380,21 @@ bool _SCSD_writeSectors (u32 sector, u32 numSectors, const void* buffer) {
 		
 		offset += BYTES_PER_READ;
 		data += BYTES_PER_READ;
+		
+		// Wait until card is finished programming
+		i = WRITE_TIMEOUT;
+		responseBuffer[3] = 0;
+		do {
+			_SCSD_sendCommand (SEND_STATUS, _SCSD_relativeCardAddress);
+			_SCSD_getResponse_R1 (responseBuffer);
+			i--;
+			if (i <= 0) {
+				return false;
+			}
+		} while (((responseBuffer[3] & 0x1f) != ((SD_STATE_TRAN << 1) | READY_FOR_DATA)));
 	}
 	
 	return true;
-
 }
 
 bool _SCSD_clearStatus (void) {

source/disc_io/io_scsd.h

@@ -29,6 +29,9 @@
 
 	2006-07-11 - Chishm
 		* Original release
+
+	2006-07-22 - Chishm
+		* First release of stable code
 */
 
 #ifndef IO_SCSD_H

source/disc_io/io_scsd_s.s

@@ -0,0 +1,128 @@
+@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
+@	io_scsd_s.s
+@
+@	Hardware Routines for reading a Secure Digital card
+@	using the SC SD
+@	
+@	Based on code supplied by Romman
+@
+@ Copyright (c) 2006 Michael "Chishm" Chisholm
+@	
+@ Redistribution and use in source and binary forms, with or without modification,
+@ are permitted provided that the following conditions are met:
+@
+@  1. Redistributions of source code must retain the above copyright notice,
+@     this list of conditions and the following disclaimer.
+@  2. Redistributions in binary form must reproduce the above copyright notice,
+@     this list of conditions and the following disclaimer in the documentation and/or
+@     other materials provided with the distribution.
+@  3. The name of the author may not be used to endorse or promote products derived
+@     from this software without specific prior written permission.
+@
+@ THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+@ WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
+@ AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE
+@ LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+@ DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+@ LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+@ THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+@ (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+@ EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+@
+@	2006-07-22 - Chishm
+@		* First release of stable code
+@
+@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
+
+    .align 4
+	.arm
+	
+	.equ	REG_SCSD_DATAWRITE,	0x09000000
+	.equ	BYTES_PER_READ,	0x200
+	.equ	SCSD_STS_BUSY,	0x100
+	.equ	BUSY_WAIT_TIMEOUT, 0x10000
+	.equ	FALSE,	0
+	.equ	TRUE,	1
+
+@ bool _SCSD_writeData_s (u8 *data, u16* crc)
+
+    .global _SCSD_writeData_s
+	
+_SCSD_writeData_s:
+	stmfd   r13!, {r4-r5}
+	mov		r5, #BYTES_PER_READ
+	mov		r2, #REG_SCSD_DATAWRITE
+
+@ Wait for a free data buffer on the SD card
+	mov		r4, #BUSY_WAIT_TIMEOUT
+_SCSD_writeData_busy_wait:
+	@ Test for timeout
+	subs	r4, r4, #1
+	moveq	r0, #FALSE			@ return false on failure
+	beq		_SCSD_writeData_return
+	@ Check the busy bit of the status register
+	ldrh	r3, [r2]   
+	tst		r3,	#SCSD_STS_BUSY
+	beq		_SCSD_writeData_busy_wait
+
+	ldrh	r3, [r2]   			@ extra clock
+
+	mov		r3, #0 				@ start bit
+	strh	r3,[r2]
+	
+@ Check if the data buffer is aligned on a halfword boundary
+	tst		r0, #1
+	beq		_SCSD_writeData_data_loop
+	
+@ Used when the source data is unaligned
+_SCSD_writeData_data_loop_unaligned:
+		ldrb	r3, [r0], #1
+		ldrb	r4, [r0], #1
+		orr		r3, r3, r4, lsl #8
+		stmia   r2, {r3-r4}  
+	subs    r5, r5, #2                 
+    bne     _SCSD_writeData_data_loop_unaligned
+	b		_SCSD_writeData_crc
+	
+@ Write the data to the card
+@ 4 halfwords are transmitted to the Supercard at once, for timing purposes
+@ Only the first halfword needs to contain data
+_SCSD_writeData_data_loop:
+		ldrh	r3, [r0], #2
+		stmia   r2, {r3-r4}  
+	subs    r5, r5, #2                 
+    bne     _SCSD_writeData_data_loop 
+	
+@ Send the data CRC
+_SCSD_writeData_crc:
+	cmp		r1, #0
+	movne	r0, r1
+	movne	r1, #0
+	movne	r5, #8
+	bne		_SCSD_writeData_data_loop 
+
+	mov		r3, #0xff 			@ end bit
+	strh	r3, [r2]
+
+@ Wait for the SD card to signal that it is finished recieving
+	mov		r4, #BUSY_WAIT_TIMEOUT
+_SCSD_writeData_finished_wait:
+	@ Test for timeout
+	subs	r4, r4, #1
+	moveq	r0, #FALSE			@ return false on failure
+	beq		_SCSD_writeData_return
+	@ Check the busy bit of the status register
+	ldrh	r3, [r2]   
+	tst		r3, #0x100
+	bne		_SCSD_writeData_finished_wait
+
+@ Send 8 more clocks, as required by the SD card
+	ldmia   r2, {r3-r4} 
+
+@ return true for success
+	mov 	r0, #TRUE
+	
+_SCSD_writeData_return:
+	ldmfd	r13!,{r4-r5}
+	bx      r14
+

source/disc_io/io_sd_common.h

@@ -52,6 +52,7 @@
 #define READ_SINGLE_BLOCK 17
 #define READ_MULTIPLE_BLOCK 18
 #define WRITE_BLOCK 24
+#define WRITE_MULTIPLE_BLOCK 25
 #define APP_CMD 55
 
 /* SD App commands */

source/file_allocation_table.c

@@ -28,6 +28,9 @@
 
 	2006-07-11 - Chishm
 		* Original release
+		
+	2006-07-11 - Chishm
+		* Made several fixes related to free clusters, thanks to Loopy
 */
 
 
@@ -202,6 +205,7 @@ u32 _FAT_fat_linkFreeCluster(PARTITION* partition, u32 cluster) {
 	u32 firstFree;
 	u32 curLink;
 	u32 lastCluster;
+	bool loopedAroundFAT = false;
 
 	lastCluster =  partition->fat.lastCluster;
 
@@ -211,7 +215,7 @@ u32 _FAT_fat_linkFreeCluster(PARTITION* partition, u32 cluster) {
 
 	// Check if the cluster already has a link, and return it if so
 	curLink = _FAT_fat_nextCluster(partition, cluster);
-	if ((curLink >= CLUSTER_FIRST) && (curLink < lastCluster)) {
+	if ((curLink >= CLUSTER_FIRST) && (curLink <= lastCluster)) {
 		return curLink;	// Return the current link - don't allocate a new one
 	}
 	
@@ -223,13 +227,20 @@ u32 _FAT_fat_linkFreeCluster(PARTITION* partition, u32 cluster) {
 	}
 
 	// Search until a free cluster is found
-	while ((_FAT_fat_nextCluster(partition, firstFree) != CLUSTER_FREE) && (firstFree <= lastCluster)) {
+	while (_FAT_fat_nextCluster(partition, firstFree) != CLUSTER_FREE) {
 		firstFree++;
-	}
+		if (firstFree > lastCluster) {
-	if (firstFree > lastCluster) {
+			if (loopedAroundFAT) {
-		// If couldn't get a free cluster then return, saying this fact
+				// If couldn't get a free cluster then return, saying this fact
-		partition->fat.firstFree = firstFree;
+				partition->fat.firstFree = firstFree;
-		return CLUSTER_FREE;
+				return CLUSTER_FREE;
+			} else {
+				// Try looping back to the beginning of the FAT
+				// This was suggested by loopy
+				firstFree = CLUSTER_FIRST;
+				loopedAroundFAT = true;
+			}
+		}
 	}
 	partition->fat.firstFree = firstFree;
 
@@ -254,6 +265,11 @@ bool _FAT_fat_clearLinks (PARTITION* partition, u32 cluster) {
 	if ((cluster < 0x0002) || (cluster > partition->fat.lastCluster))
 		return false;
 		
+	// If this clears up more space in the FAT before the current free pointer, move it backwards
+	if (cluster < partition->fat.firstFree) {
+		partition->fat.firstFree = cluster;
+	}
+
 	while ((cluster != CLUSTER_EOF) && (cluster != CLUSTER_FREE)) {
 		// Store next cluster before erasing the link
 		nextCluster = _FAT_fat_nextCluster (partition, cluster);

source/partition.c

@@ -112,7 +112,7 @@ static PARTITION* _FAT_partition_constructor ( IO_INTERFACE* disc, u32 cacheSize
 	PARTITION* partition;
 	int i;
 	u32 bootSector;
-	u8 sectorBuffer[BYTES_PER_READ];
+	u8 sectorBuffer[BYTES_PER_READ] = {0};
 
 	// Read first sector of disc
 	if ( !_FAT_disc_readSectors (disc, 0, 1, sectorBuffer)) {
@@ -156,7 +156,7 @@ static PARTITION* _FAT_partition_constructor ( IO_INTERFACE* disc, u32 cacheSize
 
 	partition = (PARTITION*) _FAT_mem_allocate (sizeof(PARTITION));
 	if (partition == NULL) {
-		return false;
+		return NULL;
 	}
 
 	// Set partition's disc interface