valutazioni - 3, GPA: 4.3 ( )

Produttore : Fujitsu File Size : 1.89 mb File Nome : Lingua di insegnamento:

L . DV Start head No. /LBA [MSB] 1F5H(CH) 1F4H(CL) 1F3H(SN) 1F2H(SC) 1F1H(FR) Start cylinder No. [MSB] / LBA Start cylinder No. [LSB] / LBA Start sector No. / LBA [LSB] Transfer sector count xx At command completion (I/O registers contents to be read) 1F7H(ST) Status information 1F6H(DH) . L . DV End head No. /LBA [MSB] 1F5H(CH) 1F4H(CL) 1F3H(SN) 1F2H(SC) 1F1H(ER) End cylinder No. [MSB] / LBA End cylinder No. [LSB] / LBA End sector No. / LBA [LSB] 00(*1) Error information *1 If the command is terminated due to an error, the remaining number of sectors for which data was not transferred is set in this register. 5-20 C141-E050-02EN 5.3 Host Commands (3) READ DMA (X’C8’ or X’C9’) This command operates similarly to the READ SECTOR(S) command except for following events. • The data transfer starts at the timing of DMARQ signal assertion. • The device controls the assertion or negation timing of the DMARQ signal. • The device posts a status as the result of command execution only once at completion of the data transfer. When an error, such as an unrecoverable medium error, that the command execution cannot be continued is detected, the data transfer is stopped without transferring data of sectors after the erred sector. The device generates an interrupt using the INTRQ signal and posts a status to the host system. The format of the error information is the same as the READ SECTOR(S) command. In LBA mode The logical block address is specified using the start head No., start cylinder No., and first sector No. fields. At command completion, the logical block address of the last sector and remaining number of sectors of which data was not transferred, like in the CHS mode, are set. The host system can select the DMA transfer mode by using the SET FEATURES command. 1) Single word DMA transfer mode 0 to 2 2) Multiword DMA transfer mode 0 to 2 3) Ultra DMA transfer mode 0 to 2 At command issuance (I/O registers setting contents) 1F7H(CM) 1 1 0 0 1 0 0 R 1F6H(DH) . L . DV Start head No. /LBA [MSB] 1F5H(CH) 1F4H(CL) 1F3H(SN) 1F2H(SC) 1F1H(FR) Start cylinder No. [MSB] / LBA Start cylinder No. [LSB] / LBA Start sector No. / LBA [LSB] Transfer sector count xx R = 0 ® with Retry R = 1 ® without Retry C141-E050-02EN 5-21 Interface At command completion (I/O registers contents to be read) 1F7H(ST) Status information 1F6H(DH) . L . DV End head No. /LBA [MSB] 1F5H(CH) 1F4H(CL) 1F3H(SN) 1F2H(SC) 1F1H(ER) End cylinder No. [MSB] / LBA End cylinder No. [LSB] / LBA End sector No. / LBA [LSB] 00 (*1) Error information *1 If the command is terminated due to an error, the remaining number of sectors of which data was not transferred is set in this register. (4) READ VERIFY SECTOR(S) (X’40’ or X’41’) This command operates similarly to the READ SECTOR(S) command except that the data is not transferred to the host system. After all requested sectors are verified, the device clears the BSY bit of the Status register and generates an interrupt. Upon the completion of the command execution, the command block registers contain the cylinder, head, and sector number of the last sector verified. If an error occurs, the verify operation is terminated at the sector where the error occurred. The command block registers contain the cylinder, the head, and the sector addresses (in the CHS mode) or the logical block address (in the LBA mode) of the sector where the error occurred. The Sector Count register indicates the number of sectors that have not been verified. If a correctable error is found, the device sets the CORR bit of the Status register to 1 after the command is completed (before the device generates an interrupt). 5-22 C141-E050-02EN 5.3 Host Commands At command issuance (I/O registers setting contents) 1F7H(CM) 0 1 0 0 0 0 0 R 1F6H(DH) . L . DV Start head No. /LBA [MSB] 1F5H(CH) 1F4H(CL) 1F3H(SN) 1F2H(SC) 1F1H(FR) Start cylinder No. [MSB] / LBA Start cylinder No. [LSB] / LBA Start sector No. / LBA [LSB] Transfer sector count xx R = 0 ®with Retry R = 1 ®without Retry At command completion (I/O registers contents to be read) 1F7H(ST) Status information 1F6H(DH) . L . DV End head No. /LBA [MSB] 1F5H(CH) 1F4H(CL) 1F3H(SN) 1F2H(SC) 1F1H(ER) End cylinder No. [MSB] / LBA End cylinder No. [LSB] / LBA End sector No. / LBA [LSB] 00 (*1) Error information *1 If the command is terminated due to an error, the remaining number of sectors of which data was not transferred is set in this register. (5) WRITE SECTOR(S) (X’30’ or X’31’) This command writes data of sectors from the address specified in the Device/Head, Cylinder High, Cylinder Low, and Sector Number registers to the address specified in the Sector Count register. Number of sectors can be specified to 256 sectors in maximum. Data transfer begins at the sector specified in the Sector Number register. For the DRQ, INTRQ, and BSY protocols related to data transfer, see Subsection 5.4.2. If the head is not on the track specified by the host, the device performs a implied seek. After the head reach...

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