NOTE1: The Parallel Port Control register reads as “Cable Not Connected” when the Parallel Port FDC
is enabled; i.e., STROBE = AUTOFD = SLC = 0 and nINIT = 1.
TABLE 47 - FDC PARALLEL PORT PINS
SPP MODE PIN DIRECTION
FDC MODE
PIN DIRECTION
nSTROBE
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I
(nDS0)
I/(O) Note1
PD0
nINDEX
nTRK0
nWP
I
PD1
I
PD2
I
PD3
nRDATA
nDSKCHG
-
I
PD4
I
PD5
-
PD6
(nMTR0)
-
I/(O) Note1
PD7
-
nACK
BUSY
PE
nDS1
O
O
O
O
O
O
O
O
I
nMTR1
nWDATA
nWGATE
DRVDEN0
nHDSEL
nDIR
I
SLCT
nALF
nERROR
nINIT
nSLCTIN
I
I/O
I
I/O
I/O
nSTEP
Note 1: These pins are outputs in mode PPFD2, inputs in mode PPFD1.
Refer to Force Write Protect in the Floppy Disk Controller section for information on the Floppy disk
Controller Force Write Protect function.
POWER MANAGEMENT
Power management capabilities are provided for
the following logical devices: floppy disk, UART 1,
UART 2 and the parallel port. For each logical
device, two types of power management are
provided; direct powerdown and auto powerdown.
Auto Power Management is enabled by CR23-B0.
When set, this bit allows FDC to enter powerdown
when all of the following conditions have been met:
1. The motor enable pins of register 3F2H are
inactive (zero).
FDC Power Management
2. The part must be idle; MSR=80H and INT = 0
(INT may be high even if MSR = 80H due to
polling interrupts).
Direct power management is controlled by CR22.
Refer to CR22 for more information.
3. The head unload timer must have expired.
110
SMSC [ SMSC CORPORATION ]
