Fujitsu MHY2160BS, MHY2200BS, MHY2120BS, MHY2040BS, MHY2080BS Outline of the Shadow Block Register

5.2 Logical Interface

5.2.2 Outline of the Shadow Block Register

Each transport layer in the host system and device has a block register, which is called a Shadow Block Register in the host system, and a Block Register in the device.

These registers are used when the host system issues a command to the device.

Table 5.3 Shadow Block Register

Command Block registers

Read		Write
	Data Port
Error		Features
Sector Count (exp)	Sector Count	Sector Count (exp)	Sector Count
Sector Number (exp)	Sector Number	Sector Number (exp)	Sector Number
Cylinder Low (exp)	Cylinder Low	Cylinder Low (exp)	Cylinder Low
Cylinder High (exp)	Cylinder High	Cylinder High (exp)	Cylinder High
	Device / Head
Status		Command
	Control Block registers
Alternate Status		Device Control

Note: Each of the Sector Count, Sector Number, Cylinder Low, and Cylinder High fields has a higher-order field used for issuing the Ext command. The fields are called Sector Count exp, Sector Number exp, Cylinder Low exp, and Cylinder High exp, respectively. For information on writing data to these fields, see "Device Control Field."

C141-E269 5-13