Samsung M9T manual Execute Device Diagnostics 90h, Flush Cache E7h, EAh extended, Format Track 50h

8.2.4Execute Device Diagnostics (90h)

This command performs the internal diagnostic tests implemented by the drive. The Diagnostic Code written to the Error register is a unique 8-bit code.

	Table 8-4 Diagnostic Codes
Code	Description
01h	No error detected
02h	Formatter device error
03h	Sector buffer error
04h	ECC circuitry error
05h	Controlling microprocessor error

8.2.5Flush Cache (E7h, EAh: extended)

This command is used by the host to request the drive to flush the write cache. If write is to be flushed, all data cached will be written to the media. The BSY bit will remain set to one until all data has been successfully written or error occurs.

8.2.6Format Track (50h)

This command is obsolete in the ATA7 specification. The supporting of this command is for backward compatibility purpose.

8.2.7Identify Device (ECh)

The Identify Device command enables the host to receive parameter information from the device. When the command is issued, prepares to transfer the 256 words of device identification data to the host, sets the DRQ bit, clears the BSY bit, and generates an interrupt. The host can then transfer the data by reading the Data register. The parameter words in the buffer have the arrangement and meanings defined. All reserved bits or words will remain to be zero.

Some parameters are defined as a group of bits. A word which is defined as a set of bits is transmitted with the indicated bits on the respective data bus bit (e.g., bit 15 appears on DD15).

Other parameters are defined as a sixteen-bit value. A word which is defined as a sixteen bit value places the most significant bit of the value on bit DD15 and the least significant bit on bit DD0.

Some parameters can be defined as a 32-bit value (e.g., words 57 and 58). Such fields are transferred using two word transfers. The device first transfers the least significant bits, bits 15 through 0 of the value, on bits DD15 through DD0 respectively. After the least significant bits have been transferred, the most significant bits, bits 31 through 16 of the value, are transferred on DD15 through DD0 respectively.

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