PQI DiskOnModule, Техническое описание

Страница: 17 / 19

14
Table 3 - I/O port functions and selection address
Addresses Functions
CS0- CS1- DA2 DA1 DA0 Read (DIOR-) Write (DIOW-)
N N × × × Data bus high
impedance
Note used
Control block registers
N A 0
× ×
Data bus high
impedance
Note used
N A 1 0
×
Data bus high
impedance
Note used
N A 1 1 0 Alternate Status Device Control
N A 1 1 1 (see note1) Not used
Command block registers
A N 0 0 0 Data Data
A N 0 0 1 Error Features
A N 0 1 0 Sector Count Sector Count
A N 0 1 1 Sector Number
LBA (7:0) (see note 2)
Sector Number
LBA (7:0) (see note 2)
A N 1 0 0 Cylinder Low
LBA (15:8) (see note 2)
Cylinder Low
LBA (15:8) (see note
2)
A N 1 0 1 Cylinder High
LBA (23:16) (see note 2)
Cylinder High
LBA (23:16) (see note
2)
A N 1 1 0 Device/Head
LBA (27:24) (see note 2)
Device/Head
LBA (27:24) (see note
2)
A N 1 1 1 Status Command
A A × × × Invalid address Invalid address
Key:
A = signal asserted, N = signal negated, × = don’t care
NOTES_
1 This register is obsolete. It is recommended that a device not respond to a read of this address. If a
device does respond, it shall not drive the DD7 signal to prevent possible conflict with floppy disk
implementations.
2 Mapping of registers in LBA translation.
Each register description in the following clauses contain the following format:
ADDRESS – the CS and DA address of the register.
DIRECTION – indicates if the register is read/write, read only, or write only from the host.
ACCESS RESTRICTIONS – indicates when the register may be accessed.
EFFECT – indicates the effect of accessing the register.
FUNCTIONAL DESCRIPTION – describes the function of the register.
FIELD/BIT DESCRIPTION – describes the content of the register.