16-bit High-Performance Single-Chip 10/100 Ethernet Controller with HP Auto-MDIX
Datasheet
6.3
PIO Burst Reads
In this mode, performance is improved by allowing up to 16 WORD read cycles back-to-back. PIO
Burst Reads can be performed using Chip Select (nCS) or Read Enable (nRD). Either or both of these
control signals must go high between bursts for the period specified.
A[7:5]
A[4:1]
nCS, nRD
Data Bus
Figure 6.2 PIO Burst Read Cycle Timing
Note: The “Data Bus” width is 16 bits
Table 6.4 PIO Burst Read Timing
SYMBOL
DESCRIPTION
MIN
TYP
MAX
UNITS
tcsh
tcsdv
tacyc
tasu
tadv
tah
nCS, nRD Deassertion Time
nCS, nRD Valid to Data Valid
Address Cycle Time
13
ns
ns
30
45
0
Address Setup to nCS, nRD valid
Address Stable to Data Valid
Address Hold Time
ns
40
7
0
0
ns
ns
ns
ns
tdon
tdoff
tdoh
Data Buffer Turn On Time
Data Buffer Turn Off Time
Data Output Hold Time
0
Note: A PIO Burst Read cycle begins when both nCS and nRD are asserted. The cycle ends when
either or both nCS and nRD are deasserted. They may be asserted and deasserted in any
order.
Revision 1.5 (07-18-06)
122
SMSC LAN9217
DATASHEET
SMSC [ SMSC CORPORATION ]
