Hitachi DK23EA Specifications - Page 31

6.3 Logical Interface 6.3.1 I/O Registers Communication between the host system and the device is done through I/O registers. The Command Block Registers are used for sending commands to the device or posting device status. The Control Block Registers are used for controlling the device or posting device status. The registers are listed in Table 6.3. Table 6.3 Register List Addresses Functions CS0- CS1- DA2 DA1 DA0 READ(DIOR-) WRITE(DIOW-) Command Block Registers 0 1 0 0 0 Data Data 0 1 0 0 1 Error Features 0 1 0 1 0 Sector Count Sector Count 0 1 0 1 1 Sector Number Sector Number 0 1 1 0 0 Cyl Low Cyl Low 0 1 1 0 1 Cyl High Cyl High 0 1 1 1 0 Device/Head Device/Head 0 1 1 1 1 Status Command Control Block Registers 1 0 1 1 0 Alt. Status Device Control Invalid or Not Used 0 0 ´ ´ ´ Invalid address 0 1 ´ ´ ´ Data bus high impedance (not used) 1 0 0 ´ ´ Data bus high impedance (not used) 1 0 1 0 ´ Data bus high impedance (not used) '0' is low signal level. '1' is high signal level. 6.3.1.1 Data register A 16-bit register to be used for transferring data blocks between the HDD's data buffer and the host. 6.3.1.2 Error register This register stores device status when the last command has been completed or diagnostic codes when a self-diagnostic process has been completed. The contents of this register are valid when the error bit (ERR) is set in the Status Register. The contents of this register are diagnostic codes when the device has just completed a self-diagnostic process requested when turning on the power or resetting. K6602637 Rev.3 02.27.01 - 31 -