PC87332VLJ-5 NSC [National Semiconductor], PC87332VLJ-5 Datasheet - Page 81

• Manufacturer Part Number: PC87332VLJ-5
• Description: PC87332VLJ (3.3V/5V) and PC87332VLJ-5 (5V) (SuperI/OTM III Premium Green) Floppy Disk Controller, Dual UARTs, IEEE1284 Parallel Port, and IDE Interfac
• Manufacturer: NSC [National Semiconductor]

8 0 Integrated Device Electronics Interface (IDE)
The two ’LS245 chips are used to enable or TRI-STATE the
data bus signals In the PC-AT mode the PC87332 provides
the two hard disk chip selects (HCS0 HCS1) for the IDE
interface
The HCS0 output is active low when the 1F0–1F7h I O
address space is chosen and corresponds to the 1FX signal
on the IDE header
The HCS1 output is active low when the 3F6 or 3F7 I O
addresses are chosen and corresponds to 3FX on the IDE
header These are the two address blocks used in the
PC-AT hard disk controller
Table 8-1 summarizes the addresses used by the PC-AT
hard disk controller
The equations shown in Figure 8-1 define the signals of the
PC87332 IDE pins
HCS0
HCS1
IDELO
IDEHI
IDED7 (read)
IDED7 (write)
e
e
e
e
A9 A8 A7 A6 A5 A4 A3 AEN
A9 A8 A7 A6 A5 A4 A3 A2 A1 AEN
IOCS16 HCS0 (RD
HCS0 (RD
e
e
(HCS0 RD)
WR HCS0
a
WR)
Equations
a
a
FIGURE 8-1 IDE Interface Signal Equations (Non-DMA)
a
a
(HCS1 A0)
(HCS1 A0) RD
WR)
HCS1
(WR A0)
a
RD
81
Note Data bus bit D7 is dedicated to the floppy disk controller at this ad-
Address
TABLE 8-1 IDE Registers and Their ISA Addresses
1F0
1F1
1F2
1F3
1F4
1F5
1F6
1F7
3F6
3F7
dress When reading this address the floppy disk controller disk
change status will be provided by bit D7 There is no write function at
this address in the IDE associated with this bit
Active at 1F0 – 1F7
Active at 3F6 3F7
Write 1F0– 1F7 3F6 Read 1F0– 1F7 3F6 3F7
Read or Write 1F0– 1F7 in AT Mode
Provides D7 during Read 1F0– 1F7 and 3F6
Provides D7 during Write 1F0– 1F7 and 3F6
(Continued)
Data
Error
Sector Count
Sector Number
Cylinder Low
Cylinder High
Drive Head
Status
Alternate Status
Drive Address
(Note)
Read Function
Comments
Data
Features
(Write Precomp)
Sector Count
Sector Number
Cylinder Low
Cylinder High
Drive Head
Command
Device Control
Not Used
Data Bus TRI-STATE
Write Function