SIO10N268 Datasheet, PDF (237/251 Pages) SMSC Corporation – Advenced Notebook I/O for ISA or LPC Designs with X-Bus Interface for I/O, Memory, and FWH Emulation and Four Srial Ports

Advanced Notebook I/O for ISA or LPC Designs
Datasheet
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 12.27.
12.8.7 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.
PD<0:7>
t6
t3
nSTROBE
t1
t2
t5
BUSY
t4
Figure 12.25 - Parallel Port FIFO Timing
NAME
t1
t2
t3
t4
t5
t6
DESCRIPTION
PDATA Valid to nSTROBE Active
nSTROBE Active Pulse Width
PDATA Hold from nSTROBE Inactive (Note 12.7)
nSTROBE Active to BUSY Active
BUSY Inactive to nSTROBE Active
BUSY Inactive to PDATA Invalid (Note 12.7)
MIN TYP MAX UNITS
600
ns
600
ns
450
ns
500
ns
680
ns
80
ns
Note 12.7 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.
SMSC SIO10N268
Page 239
DATASHEET
Rev. 0.5 (03-24-05)