LSI Logic Confidential
18-20
Specifications
Copyright © 2001, 2002 by LSI Logic Corporation. All rights reserved.
18.2.4 SDRAM Interface AC Timing
SDRAM AC Timing diagrams are described in the sections that follow.
18.2.4.1
Clock Signals to SDRAM
The clock signal to the SDRAM is driven from the DMN-8600. For SDR
SDRAM, only the SDRAM_CLK output is used to connect to the clock
input of the DRAM. For DDR SDRAM, the differential clock signal is
used, and both SDRAM_CLK and SDRAM_CLK are connected to CLK
and CLK of the DRAM, respectively.
For SDR mode operation, the Clock high (low) period is defined as the
period when the clock signal is above (below) the defined Vih (Vil)
voltage level. For DDR mode, the crossing of CLK and CLK is used as
the reference.
Table 18.10 M-Mode Read AC Timing Parameters
1
Symbo
l
Description
Timing Value
Min
Max
T
1
H_ADDR[2:0] input setup time with respect to H_CS falling. 3.0 ns
–
T
2
H_ADDR[2:0] input hold time with respect to H_CS falling.
2.0 ns
–
T
3
H_WAIT output delay time with respect to H_CS falling.
–
3 14 ns
T
4
H_WAIT assertion period.
2 cycles
–
T
5
H_DTACK output delay time with respect to H_CS falling.
–
3 14 ns
T
6
H_DTACK assertion period.
2 cycles
–
T
7
Delay from H_WAIT rising to data valid.
–
1 cycle
T
8
Delay from RD rising to data float.
2 cycles
–
T
9
Output delay from H_CS rising to H_WAIT 3-stated.
2 cycles
3 cycles
T
10
Output delay from H_CS rising to H_DTACK 3-stated.
2 cycles
3 cycles
T
11
H_CS hold time with respect to H_WAIT rising.
2.0 ns
–
T
12
H_CS hold time with respect to DTACK falling.
2.0 ns
–
1. H_WAIT and H_DTACK are pulled up by an internal pull-up on 3-state.