LAN9115_05 Datasheet, PDF (120/131 Pages) SMSC Corporation – Highly Efficient Single- Chip 10/100 Non-PCI Ethernet Controller

Highly Efficient Single-Chip 10/100 Non-PCI Ethernet Controller
Datasheet
Table 6.5 RX Data FIFO Direct PIO Read Timing
SYMBOL
t_cycle
t_csl
t_csh
t_csdv
t_asu
t_ah
t_don
t_doff
t_doh
DESCRIPTION
Read Cycle Time
nCS, nRD Assertion Time
nCS, nRD Deassertion Time
nCS, nRD Valid to Data Valid
Address, FIFO_SEL Setup to nCS, nRD Valid
Address, FIFO_SEL Hold Time
Data Buffer Turn On Time
Data Buffer Turn Off Time
Data Output Hold Time
MIN
TYP
165
32
13
0
0
0
0
MAX
30
7
UNITS
ns
ns
ns
ns
ns
ns
ns
ns
ns
Note: An RX Data FIFO Direct PIO Read cycle begins when both nCS and nRD are asserted. The
cycle ends when either or both nCS and nRD are de-asserted. They may be asserted and de-
asserted in any order.
6.5
RX Data FIFO Direct PIO Burst Reads
In this mode the upper address inputs are not decoded, and any burst read of the LAN9115 will read
the RX Data FIFO. This mode is enabled when FIFO_SEL is driven high during a read access. This
is normally accomplished by connecting the FIFO_SEL signal to a high-order address line. This mode
is useful when the host processor must increment its address when accessing the LAN9115. Timing
is identical to a PIO Burst Read, and the FIFO_SEL signal has the same timing characteristics as the
address lines.
In this mode, performance is improved by allowing an unlimited number of back-to-back DWORD or
WORD read cycles. RX Data FIFO Direct PIO Burst Reads can be performed using Chip Select (nCS)
or Read Enable (nRD). When either or both of these control signals go high, they must remain high
for the period specified.
Note that address lines A[2:1] are still used, and address bits A[7:3] are ignored.
Revision 1.1 (05-17-05)
120
DATASHEET
SMSC LAN9115