LPC47M192 datasheet(207/228 Pages) SMSC

207 / 228 page

SMSC DS – LPC47M192

Page 207

Rev. 03/30/05

DATASHEET

Output Drivers

To facilitate higher performance data transfer, the use of balanced CMOS active drivers for critical signals (Data,

HostAck, HostClk, PeriphAck, PeriphClk) are used in ECP Mode. Because the use of active drivers can present

compatibility problems in Compatible Mode (the control signals, by tradition, are specified as open-drain), the drivers

are dynamically changed from open-drain to push-pull. The timing for the dynamic driver change is specified in then

IEEE 1284 Extended Capabilities Port Protocol and ISA Interface Standard, Rev. 1.14, July 14, 1993, available

from Microsoft. The dynamic driver change must be implemented properly to prevent glitching the outputs.

FIGURE 28 - PARALLEL PORT FIFO TIMING

NAME

DESCRIPTION

MIN

TYP

MAX

UNITS

PDATA Valid to nSTROBE Active

600

nSTROBE Active Pulse Width

600

PDATA Hold from nSTROBE Inactive (Note 1)

450

nSTROBE Active to BUSY Active

500

BUSY Inactive to nSTROBE Active

680

BUSY Inactive to PDATA Invalid (Note 1)

Note 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.

PD<7:0>

nSTROBE

BUSY

LPC47M192 Datasheet(PDF) 207 Page - SMSC Corporation