FDC37C669_07 SMSC [SMSC Corporation], FDC37C669_07 Datasheet - Page 94

• Manufacturer Part Number: FDC37C669_07
• Description: PC 98/99 Compliant Super I/O Floppy Disk Controller with Infrared Support
• Manufacturer: SMSC [SMSC Corporation]

Data or Address cycle.
active low when nWAIT is active low during the
EPP cycle. This can be used to extend the cycle
time.
nWAIT is inactive high.
Write Sequence of Operation
1.
2.
3.
4.
5.
6.
7.
The host sets PDIR bit in the control
register to a logic "0".
nWRITE.
The host selects an EPP register, places
data on the SData bus and drives nIOW
active.
The chip places address or data on PData
bus.
Chip asserts nDATASTB or nADDRSTRB
indicating that PData bus contains valid
information, and the WRITE signal is valid.
If nWAIT
deasserted until the peripheral deasserts
nWAIT or a time-out occurs.
When the host deasserts nI0W the chip
deasserts nDATASTB or nADDRSTRB and
latches the data from the SData bus for the
PData bus.
Chip may modify nWRITE, PDIR and
nPDATA in preparation of the next cycle.
The write cycle can complete when
is
asserted,
IOCHRDY is driven
IOCHRDY
This asserts
is
94
EPP 1.7 Read
The timing for a read operation (data) is shown
in timing diagram EPP 1.7 Read Data cycle.
IOCHRDY is driven active low when nWAIT is
active low during the EPP cycle. This can be
used to extend the cycle time. The read cycle
can complete when nWAIT is inactive high.
Read Sequence of Operation
1.
2.
3.
4.
5.
6.
7.
8.
9.
The host sets PDIR bit in the control
register to a logic "1".
nWRITE and tri-states the PData bus.
The host selects an EPP register and drives
nIOR active.
Chip asserts nDATASTB or nADDRSTRB
indicating that PData bus is tri-stated, PDIR
is set and the nWRITE signal is valid.
If nWAIT
deasserted until the peripheral deasserts
nWAIT or a time-out occurs.
The Peripheral drives PData bus valid.
The
indicating that PData is valid and the chip
may begin the termination phase of the
cycle.
When the host deasserts nI0R the chip
deasserts nDATASTB or nADDRSTRB.
Peripheral tri-states the PData bus.
Chip may modify nWRITE, PDIR
nPDATA in preparation of the next cycle.
Peripheral
is
asserted,
deasserts
This deasserts
IOCHRDY
nWAIT,
and
is