FDC37C665GT_07 Datasheet, PDF (148/152 Pages) SMSC Corporation – High-Performance Multi-Mode Parallel Port Super I/O Floppy Disk Controllers

open-collector), the drivers are dynamically
changed from open-collector to totem-pole. The
timing for the dynamic driver change is specified
in the IEEE 1284 Extended Capabilities Port
Protocol
and
ISA
Interface
Standard, Rev. 1.09, Jan. 7, 1993, available
from Microsoft. The dynamic driver change
must be implemented properly to prevent
glitching the outputs.
PDATA
t6
t3
nSTROBE
t1
t2
t5
t4
BUSY
Parameter
t1 DATA Valid to nSTROBE Active
t2 nSTROBE Active Pulse Width
t3 DATA Hold from nSTROBE Inactive
t4 nSTROBE Active to BUSY Active
t5 BUSY Inactive to nSTROBE Active
t6 BUSY Inactive to PDATE Invalid
min
max units Notes
600
ns
600
ns
450
ns
1
500
ns
680
ns
80
ns
1
1. The data is held until BUSY goes inactive or for time t3, whichever is longer. This only
applies if another data transfer is pending. If no other data transfer is pending, the data
is held indefinitely.
FIGURE 17 - PARALLEL PORT FIFO TIMING
148