Datasheet

11.3.2 Contiguous I/O mapped addressing

ReservedDevice AddressF11110

Device ControlAlternate StatusE01110

2Dup. FeaturesDup. ErorrD10110

2Dup. Odd WR DataDup. Odd RD Date910010

2Dup. Even WR DataDup. Even RD Data800010

CommandStatus711100

Device/HeadDevice/Head601100

Cylinder HighCylinder High510100

Cylinder LowCylinder Low400100

Sector NumberSector Number311000

Sector CountSector Count201000

2FeaturesError110000

1Even WR DataEven RD Data000000

Notes-IOWR=0-IORD=0OffsetA0A1A2A3-REG

Figure 46. Contiguous I/O mapped addressing

Notes:

1. Register 0 is accessed with -CE1 low and -CE2 low (and A0 = don't care) as a word register on the

combined Odd Data Bus and Even Data Bus (D15–D0). This register may also be accessed by a pair of

byte accesses to the offset 0 with -CE1 low and -CE2 high. The address space of this word register over-

laps the address space of the Error and Feature byte-wide registers that lie at offset 1. When accessed

twice as a byte register with -CE1 low, the first byte to be accessed is the even byte of the word and the

second byte accessed is the odd byte of the equivalent word access. A byte access to register 0 with

-CE1 high and -CE2 low accesses the error (read) or feature (write) register.

2. Registers at offset 8, 9, and D are nonoverlapping duplicates of the registers at offset 0 and 1.

are byte accessed in the order 9 and then 8 the data will be transferred by first the odd byte and then the

even byte. Repeated byte accesses to register 8 or 0 will access consecutive (even then odd) bytes from

the data buffer. Repeated word accesses to register 8, 9, or 0 will access consecutive words from the

data buffer. Repeated byte accesses to register 9 are not supported. However, repeated alternating byte

access to registers 8 and then 9 will access consecutive (even then odd) bytes from the data buffer. Byte

accesses to register 9 accesses only the odd byte of the data.

3. Address lines that are not indicated are ignored by the device for accessing all the registers in this

table.

Hard disk drive specification for DSCM-11000/-10512/-10340