User manual MAXTOR CFS270A REV A 05-1995

[. . . ] CFS270A Intelligent Disk Drive Product Manual Production Release Per ECO 6379 P/N 20401000-001 Revision A May 1995 3081 Zanker Road San Jose, CA 95134-2128 (408) 456-4500 FCC Notice This equipment generates and uses radio frequency energy and, if not installed and used properly; that is, in strict accordance with the manufacturer's instructions, may cause interference to radio and television reception. It has been type tested and found to comply with the limits for a Class B computing device in accordance with the specifications in Part 15 of FCC Rules, which are designed to provide reasonable protection against such interference in a residential installation. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause interference to radio or television reception, which can be determined by turning the equipment on and off, you are encouraged to try to correct the interference by one or more of the following measures: · · · Reorient the receiving antenna. [. . . ] r is the retry bit; 0 = retries are enabled, 1 = retries are disabled. Retries that may be enabled/disabled are those on ECC and data errors. When retries are disabled at the start of a command, they are always automatically enabled at the end of the command. PR is the features (write precomp) register. y means the register contains a valid parameter for this command. For the device/head register, y means that both the device and head parameters are used. n means the register does not contain a valid parameter for this command. · · · · · · · · Page 42 Filepro CFS270A Register Addresses and Functions Chapter 6 · · · d means only the device parameter is valid and not the head parameter. p is a valid bit for power commands E0 - E3 and E5 - E6. e means the registers contain valid parameters when performing extended commands. x = don't care. · Technical Reference Manual Page 43 Chapter 6 Register Addresses and Functions Page 44 Filepro CFS270A Command Set 7 Command Register All commands are decoded from the Command Register. The drive's host interface must be programmed by the host computer to perform commands and will return status to the host at command completion. To issue a command, the host must: · · · load the pertinent registers in the Task File activate the interrupt enable bit, -IEN, in the Digital Output register write the command code to the Command register Execution begins as soon as the Command register is written. The following sections describe the drive's supported command set. For ease of reference, the commands are listed in alphabetical order. Technical Reference Manual Page 45 Chapter 7 Command Set Conner Specific Command Number: 9A hex Description: The Conner drive provides vendor-unique commands to allow for certain operations not provided by the standard command set. The Sector Number register must be set to 9A hex and the specific command in the Sector Count register. The Cylinder High and Low registers are used to pass any bytes used in a write operation. The Conner specific command has the following decodes: Decode: 00 hex 01 hex 02 hex 03 hex 04 hex 05 hex 06 hex 07 hex 08 hex * 09 hex * 0A-FF hex Description: Get Feature Word Reserved Read drive switches Abort command Reserved Reserved Abort command Abort command Power lock Power unlock Reserved * only valid on drives which implement Conner Power commands The following sections describe these decodes in more detail. Page 46 Filepro CFS270A Command Set Chapter 7 Get Drive Feature word (00) This command fetches the drive feature word and returns it in the Cylinder High and Cylinder Low registers. The bit meaning is as follows: Bit: 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Description: Reserved Reserved Customer Reserved Reserved Reserved Reserved Reserved ATA/CAM mode = 1 Reserved Reserved Reserved (enable no spin on POR) Reserved Disable Read Look Ahead Caching Enable Write Caching Customer Reserved Customer Reserved It is important to read the Feature word and then only change the bits of interest leaving the other bits unaffected using specific commands supported by this drive. Technical Reference Manual Page 47 Chapter 7 Command Set Read the Drive Switches (02) This command returns the drive switches in the Cylinder Low Register. The bit meaning is as follows: Bit: 7 6 5 4 3 2 1 0 Description: Reserved Reserved -C/D Reserved Reserved Reserved Reserved Reserved Power Lock (08) This command prevents the drive from spinning down, and spins the drive up if the drive had been spun down. Power Unlock (09) This allows the drive to respond to the Power command and re-enables the power down time if applicable. Page 48 Filepro CFS270A Command Set Chapter 7 Execute Device Diagnostic Command Number: 90 hex Description: This command performs the internal diagnostic tests implemented by the drive. The diagnostic tests are only executed upon receipt of this command. The drive sets BSY immediately upon receipt of the command. If the drive is a master, the drive performs the diagnostic tests and saves the results. [. . . ] Data byte transfers are 16-bit transfers and ECC bytes are 8bit transfers. Write Caching Write caching is activated by setting the Feature Word bit 2. Once write caching is active, the Write Sector(s) command is cached. This command is then referred to as a "cached write. " When a cached write command is received, the data is taken from the host and ending status is posted before the data has been written to the disk. · If the next command is a cached write and the data is logically sequential, the data is taken from the host immediately. [. . . ]