PARALLEL PORT FLOPPY DISK CONTROLLER
In this mode, the Floppy Disk Control signals are
The following parallel port pins are read as follows by a
available on the parallel port pins. When this mode is
selected, the parallel port is not available. There are two
modes of operation, PPFD1 and PPFD2. These modes
can be selected in Configuration Register 4. PPFD1 has
only drive 1 on the parallel port pins; PPFD2 has drive 0
and 1 on the parallel port pins.
read of the parallel port register:
1. Data Register (read) = last Data Register (write)
2. Control Register are read as "cable not connected"
STROBE, AUTOFD and SLC = 0 and nINIT = 1;
3. Status Register reads: nBUSY = 0, PE = 0, SLCT =
0, nACK = 1, nERR = 1.
PPFD1: Drive 0 is on the FDC pins
Drive 1 is on the Parallel port pins
The following FDC pins are all in the high impedence
state when the PPFDC is actually selected by the drive
select register:
PPFD2: Drive 0 is on the Parallel port pins
Drive 1 is on the Parallel port pins
1. nWDATA, DENSEL, nHDSEL, nWGATE, nDIR,
nSTEP, nDS1, nDS0, nMTRO, nMTR1.
When the PPFDC is selected the following pins are set as
follows:
2. If PPFDx is selected, then the parallel port can not
be used as a parallel port until "Normal" mode is
selected.
1. nDACK: Assigned to the parallel port device during
configuration.
2. PDRQ (assigned to the parallel port): not ECP =
high-Z, ECP & dmaEn = 0, ECP & not dmaEn =
high-Z
The FDC signals are muxed onto the Parallel Port pins as
shown in Table 32.
3. IRQ assigned to the parallel port: not active, this is
hi-Z or Low depending on settings.
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SMSC [ SMSC CORPORATION ]
