LPC47N237-MD SMSC [SMSC Corporation], LPC47N237-MD Datasheet - Page 130

• Manufacturer Part Number: LPC47N237-MD
• Description: 3.3V I/O CONTROLLER FOR PORT REPLICATORS AND DOCKING STATIONS
• Manufacturer: SMSC [SMSC Corporation]

20.1.7 Output Drivers
Note 20.5
Revision 0.3 (10-26-04)
NAME
nSTROBE
PD<0:7>
t1
t2
t3
t4
t5
t6
handshake. The peripheral then sets PeriphClk (nACK) high. After the host has accepted the data it sets
HostAck (nALF) low, completing the transfer. This sequence is shown in Figure 20.18.
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.
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.
BUSY
PDATA Valid to nSTROBE Active
nSTROBE Active Pulse Width
PDATA Hold from nSTROBE Inactive
nSTROBE Active to BUSY Active
BUSY Inactive to nSTROBE Active
BUSY Inactive to PDATA Invalid
DESCRIPTION
Figure 20.16 – Parallel Port FIFO Timing
DATASHEET
(Note 20.5)
t1
(Note 20.5)
Page 130
t4
t2
3.3v I/O Controller for Port Replicators and Docking Stations
MIN
600
600
450
680
80
t3
TYP
t6
t5
MAX
500
SMSC DS – LPC47N237
UNITS
ns
ns
ns
ns
ns
ns