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RL-ARM mass storage sample and CD-ROM

Hi my friends!

I've used RL-ARM mass storage code from sample codes of KEIL 4.03 on AT91SAM7S256.
when I attach it to PC , the system recognizes it as a flash disk, correctly;

now I want to change it to apear as a CD-ROM in windows.

I want to know any changes in code.

can anyone help me?

thanks for your help!

Parents

0 Chinzei Tsuneo over 13 years ago in reply to meysam nabi

> first question is that in mscuser.c , we have SCSI_READ10 in definition of function MSC_BulkIn() , we must change it to 12 or not?

READ10 or READ12?
USB MSC compliance (*1) defines READ12 is required, and READ10 is optional for CD/DVD.
But Major OS (Windows/Linux/MacOSX) issues READ10 first. When READ10 fails, READ12 is applied. Therefore, you may support both of them; READ12 for compliance, READ10 for performance.

The difference of READ10 and READ12 lies in the size and location of TRANSFER LENGTH parameter.
READ10: two bytes (byte 7, 8 - starting from 0)
READ12: four bytes (byte 6, 7, 8, 9)
In the KEIL MSC implementation, MSC_RWSetup() picks up TRANSFER LENGTH from the CB (Command Block)

To support both of READ10 and READ12,
- Don't need to touch to SCSI_READ10 label and MSC_RWSetup()
- Add extra SCSI_READ12 label and MSC_RWSetup12(), which are copied from READ10 implementation, and modified.

mscuser.c
void MSC_GetCBW (void) {
   ...
   ...
      switch (CBW.CB[0]) {
        ...
        ...
        case SCSI_READ10:         // <--- don't need to touch to
          ...
          // no change
          ...
        case SCSI_READ12:         // <--- Add this label and contents
          if (MSC_RWSetup12()) {  // <--- replace to MSC_RWSetup12, the rest is same as READ10
            if ((CBW.bmFlags & 0x80) != 0) {
              AT91C_BASE_PIOA->PIO_CODR = LED1;  /* Turn On Read LED */
              BulkStage = MSC_BS_DATA_IN;
              MSC_MemoryRead();
            } else {
              USB_SetStallEP(MSC_EP_OUT);
              CSW.bStatus = CSW_PHASE_ERROR;
              MSC_SetCSW();
            }
          }
          break;

BOOL MSC_RWSetup (void) {
  ...
  // no change
  ...
}

BOOL MSC_RWSetup12 (void) {
  ...                            // <---  copy the contents of MSC_RWSetup()
  ...
  /* Number of Blocks to transfer */
//  n = (CBW.CB[7] <<  8) |      // <--- modify these lines
//      (CBW.CB[8] <<  0);

  n =   (CBW.CB[6] << 24)
      | (CBW.CB[7] << 16)
      | (CBW.CB[8] <<  8)
      | (CBW.CB[9] <<  0);
 ...
}

(*1) USB Mass Storage Class Compliance Test Specification
www.singlix.org/.../MSC-compliance-0_9a.pdf
4.2 Command Set Information

Tsuneo

Reply

0 Chinzei Tsuneo over 13 years ago in reply to meysam nabi

> first question is that in mscuser.c , we have SCSI_READ10 in definition of function MSC_BulkIn() , we must change it to 12 or not?

mscuser.c
void MSC_GetCBW (void) {
   ...
   ...
      switch (CBW.CB[0]) {
        ...
        ...
        case SCSI_READ10:         // <--- don't need to touch to
          ...
          // no change
          ...
        case SCSI_READ12:         // <--- Add this label and contents
          if (MSC_RWSetup12()) {  // <--- replace to MSC_RWSetup12, the rest is same as READ10
            if ((CBW.bmFlags & 0x80) != 0) {
              AT91C_BASE_PIOA->PIO_CODR = LED1;  /* Turn On Read LED */
              BulkStage = MSC_BS_DATA_IN;
              MSC_MemoryRead();
            } else {
              USB_SetStallEP(MSC_EP_OUT);
              CSW.bStatus = CSW_PHASE_ERROR;
              MSC_SetCSW();
            }
          }
          break;

BOOL MSC_RWSetup (void) {
  ...
  // no change
  ...
}

BOOL MSC_RWSetup12 (void) {
  ...                            // <---  copy the contents of MSC_RWSetup()
  ...
  /* Number of Blocks to transfer */
//  n = (CBW.CB[7] <<  8) |      // <--- modify these lines
//      (CBW.CB[8] <<  0);

  n =   (CBW.CB[6] << 24)
      | (CBW.CB[7] << 16)
      | (CBW.CB[8] <<  8)
      | (CBW.CB[9] <<  0);
 ...
}

(*1) USB Mass Storage Class Compliance Test Specification
www.singlix.org/.../MSC-compliance-0_9a.pdf
4.2 Command Set Information

Tsuneo

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