PARALLEL PORT FLOPPY DISK CONTROLLER
In this mode, the Floppy Disk Control signals
The following parallel port pins are read as
follows by a read of the parallel port register:
are 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.
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
When the PPFDC is selected the following pins
are set as follows:
1. nWDATA, DENSEL, nHDSEL, nWGATE,
nDIR, nSTEP, nDS1, nDS0, nMTRO,
nMTR1.
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
2. If PPFDx is selected, then the parallel port
can not be used as a parallel port until
"Normal" mode is selected.
3. IRQ assigned to the parallel port: not active,
this is hi-Z or Low depending on settings.
The FDC signals are muxed onto the Parallel
Port pins as shown in Table 32.
71
SMSC [ SMSC CORPORATION ]
