The MSD code has many serious bugs that cause intermittant problems. Here are the solutions from a 24 hour hack that I did.

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I have made so many changes that it is difficult to relate them to the original code. I will try.

1. The FLASH timing flag is missing. Add:

	
FLSCL |= 0x90;	// set 48MHz for flash

At the bottom of the clock set if you are using USB_4X_CLOCK.

2. A trick I got from Tsuneo, if you are not bus powered, disable suspend:

POLL_WRITE_BYTE(POWER,  0x00);          // disable USB0 suspend detection

Everywhere there is a POWER. I also added it just before setting the ports in Port_Init() just to be safe.

3. [Removed]

4. Add a short delay before setting the crossbar in Port_Init();

for(i=0;i<5000;i++) Delay();	
//XBARE = 1;                              // Enable Crossbar
XBR1 |= 0x40;

5. In the descriptors:

A. configuration_descriptor - bmAttributes - If you are not bus-powered, change to 0xC0 from 0x80. This will prevent random overheats in the usb hub.

B. when Get_Descriptor() is called with DSC_CONFIG, the whole set needs to be returned, configuration_descriptor, interface_descriptor, and the two endpoint_descriptors. Group them into one structure containing all four, and return that structure and the size of the super-struct.

C. Get_Descriptor() - DSC_STRING - String #3 the serial number. Always remember to return a unique number in UNICODE.

6. I turned on Reset_MSD() and Get_MaxLUN() although I'm not sure they are needed.

7. in ISR.c

A. Important! Change USB_In to return a true or false depending on if Handle_In() is called. This is important later.

B. Disable interrupts around the code in Handle_In1(). It uses EINCSR1, which is indexed by INDEX. EINCSR1 is also called inside the interrupt, with a different INDEX!

8. In MSD_MSD.c.

A. Mistake - the MSD_READY code is very flawed. It throws out many good packets. Here is fixed code:

	case MSD_READY:
		if(Out_Count) 
		{
			static BYTE xdata Out_Packet[EP2_PACKET_SIZE];
			static unsigned outc;
			
			  // Look for a "valid" and "meaningful" CBW, as defined in the spec:
			outc = Out_Count;
			
			 // Get the Data - use Out_Packet in case it is more than 29 bytes
			Out2_Get_Data(Out_Packet);
			Out2_Done();
	
			if( outc < sizeof(CBW) )
			{
				 // Garbage
				return;
			}
	
			cbw = *(CBW*)Out_Packet;
			
			 // Valid signature?
			if( cbw.dCBWSignature != CBW_SIGNATURE ) return;
			
			 // Valid CBW length?
			if( ((cbw.bCBWCBLength>16) || (cbw.bCBWCBLength<1)) ) return;
			
			 // LUN for me?
			if( (cbw.bCBWLUN!=0x00) ) return;
			
			 // do the data
			Msd_State=MSD_DATA;
		}
		break;

B. The MSD_STATUS_TRANSPORT assumes that the data is sent. That is incorrect. MSD can jam if the data is not sent. Based on setting the USB_In() to return a value:

	case MSD_STATUS_TRANSPORT:
		// Reply with a CSW:
		csw.dCSWSignature=CSW_SIGNATURE;
		csw.dCSWTag=cbw.dCBWTag;
		csw.bCSWStatus=Scsi_Status;
		csw.dCSWDataResidue=ntohl(Scsi_Residue);
		
		// Send the CSW
		if( USB_In((BYTE*)&csw,sizeof(CSW)) )
		{
			// Success!
			Msd_State=MSD_READY;
		}
		else
		{
			 // Keep trying until I get something new
			if( Out_Count )
				Msd_State=MSD_READY;
		}
		break;
 

This will keep trying until it succeeds or a recovery packet is sent.

9. MSD_scsi.c – This is really messed up. I rewrote it, so here are some of my basic changes:

A. The Scsi_Standard_Inquiry_Data structure.

The response format should be 0, not 2.
There are eight bytes of data missing. Make sure the Mass Storage descriptor is complete, and that there is a version number.

code const BYTE Scsi_Standard_Inquiry_Data[36]= {
  0x00, // Peripheral qualifier & peripheral device type
  0x80, // Removable medium
  0x05, // Version of the standard (2=obsolete, 5=SPC-3)
  0x00, // No NormACA, No HiSup, response data format=2
  0x1F, // No extra parameters
  0x00, // No flags
  0x80, // 0x80 => BQue => Basic Task Management supported
  0x00, // No flags
  'S','i','L','a','b','s',' ',' ', // Requested by Dekimo via www.t10.org
  'M','a','s','s',' ','S','t','o','r','a','g','e',' ',' ',' ',' ',
  '1','.','0','0'
};
 

B. Mode Sense 6 should NOT be used. Mode Sense 10 is the one allowed for Mass Storage. And you also need to add the Flex Disk descriptor:

code const BYTE __Scsi_Mode_Sense_10[8] = 
	{ 0x00,0x26,0,0,0,0,0,0 }; // No mode sense parameter
#define	bedistsb(s)  	(BYTE)((((unsigned short)s)>>8)&0x0FF), (BYTE)(((( unsigned short)s))&0x0FF)
#define _CYL(l)		(((l)/SECTORS_PER_TRACK)/(HEADS_PER_CYLINDER+1))
#define _HEAD(l)	(((l)/SECTORS_PER_TRACK)%(HEADS_PER_CYLINDER+1))
#define _SECT(l)	(((l)%SECTORS_PER_TRACK)+1)
code const BYTE __Scsi_Request_Sense_Flexible_Disk_Page[32] = 
{
	0x05, 		// Page Code
	0x1E,		// Page Length
	bedistsb(0x00FA), 	// Transfer rate
	HEADS_PER_CYLINDER,		// Heads
	SECTORS_PER_TRACK,		// Sectors/Track
	bedistsb(PHYSICAL_BLOCK_SIZE),	// Block length
	bedistsb(_CYL(MAX_SECTORS)), 	// Cylinders
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x05,		// Motor ON
	0x1E,		// Motor OFF
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	bedistsb(300), 	// rotation rate
	0x00, 0x00
};
void Scsi_Mode_Sense10() 
{
	struct ModeSenseIn
	{
		BYTE	OperationCode;
		BYTE	LUN;
		BYTE	Page;
		BYTE	Res[4];
		unsigned short	wListLen;
		BYTE	Res2;
	};
	unsigned short _maxsize = ntohs(((struct ModeSenseIn *)cbw.CBWCB)->wListLen);
	Scsi_Status=SCSI_PASSED;
	 // Return Default
	//if( cbw.CBWCB[2]&0x80 ) 
	{
		Scsi_SenseKey=SCSI_NO_SENSE;
		Scsi_SenseCode=0x00;
		Scsi_SenseQualifier=0x00;
		if( sizeof(__Scsi_Mode_Sense_10) <= _maxsize )
			_maxsize -= sizeof(__Scsi_Mode_Sense_10);
		else
		{
			Scsi_SenseKey=SCSI_ILLEGAL_REQUEST;
			Scsi_SenseCode=0x1A;  // Illegal Parameter
			Scsi_SenseQualifier=0x00;
			return;
		}
		Scsi_Send(__Scsi_Mode_Sense_10,sizeof(__Scsi_Mode_Sense_10));
		if( _maxsize >= sizeof(__Scsi_Request_Sense_Flexible_Disk_Page) )
			Scsi_Send(__Scsi_Request_Sense_Flexible_Disk_Page,sizeof(__Scsi_Request_Sense_Flexible_Disk_Page));
		return;
	}
}
 

C. And the matching call in Scsi_rx():

#define SCSI_MODE_SELECT_10					0x55
#define SCSI_MODE_SENSE_10					0x5A
    case SCSI_MODE_SENSE_10:
		Scsi_Mode_Sense10();
		break;

D. On Read10 and Write10, the big mistake is using the cbw.dCBWDataTransferLength.

void Scsi_Read10() 
{
	struct ReadIn
	{
		BYTE	OperationCode;
		BYTE	LUN;
		DWORD dwLBA;
		BYTE	Res;
		unsigned short	wTransferLen;
		BYTE	Res2;
		BYTE	PAD[2];
	};
	unsigned short i,j;
	//DWORD xdata d_len = ntohl(cbw.dCBWDataTransferLength);
	unsigned short d_len = ntohs(((struct ReadIn *)cbw.CBWCB)->wTransferLen);
	DWORD d_LBA = 0;
	for(i=2;i<6;++i)
		d_LBA = (d_LBA<<8)+cbw.CBWCB[i];
	Scsi_Status=SCSI_PASSED;
	Scsi_SenseKey=SCSI_NO_SENSE;
	Scsi_SenseCode=0x00;
	Scsi_SenseQualifier=0x00;
	for(i=0;i< d_len && (Scsi_Residue >= PHYSICAL_BLOCK_SIZE);i++) 
	{
		Sect_Read(d_LBA+i);
		for(j=0; j < (PHYSICAL_BLOCK_SIZE-1);) 
		{
			if( USB_In(Scratch+j, EP1_PACKET_SIZE) )
			{
				j += EP1_PACKET_SIZE;
			}
		}
		Scsi_Residue -= PHYSICAL_BLOCK_SIZE;
	}
}
void Scsi_Write10() 
{
	struct WriteIn
	{
		BYTE	OperationCode;
		BYTE	LUN;
		DWORD	dwLBA;
		BYTE	Res;
		unsigned short	wTransferLen;
		BYTE	Res2;
		BYTE	PAD[2];
	};
	unsigned short i,j;
	//DWORD xdata d_len = ntohl(cbw.dCBWDataTransferLength);
	DWORD d_len = ntohs(((struct WriteIn *)cbw.CBWCB)->wTransferLen);
	DWORD d_LBA = 0;
	for(i=2;i<6;++i)
		d_LBA = (d_LBA<<8)+cbw.CBWCB[i];
	Scsi_Status=SCSI_PASSED;
	Scsi_SenseKey=SCSI_NO_SENSE;
	Scsi_SenseCode=0x00;
	Scsi_SenseQualifier=0x00;
	for(i=0;(i< d_len) && (Scsi_Residue >= PHYSICAL_BLOCK_SIZE);i++) 
	{
		START_WRITE_COPY;
		for(j=0;j < PHYSICAL_BLOCK_SIZE-1;) 
		{
			while(!Out_Count);
			Out2_Get_Data(Scratch+j);
			j += Out_Count;
			Out2_Done();
		}
		STOP_WRITE_COPY;
		Sect_Write(d_LBA+i);
		Scsi_Residue-=PHYSICAL_BLOCK_SIZE;
	}
}

10. ntohs and ntohl are not defined in Keil

#define htonl(d)		((((DWORD)(d)&0xFF000000L)>>24)|(((DWORD)(d)&0x00FF0000L)>> 8)|(((DWORD)(d)&0x0000FF00L)<< 8)|(((DWORD)(d)&0x000000FFL)<<24))
#define htons(w)		(((((WORD2)w)&0xFF00u)>>8)|((((WORD2)w)&0x00FFu)<<8))
#define ntohs htons
#define ntohl htonl

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I have many many more fixes, but they have to do with the disk.

-Erik