ppc405ex Applied Micro Circuits Corporation (AMCC), ppc405ex Datasheet - Page 67

• Manufacturer Part Number: ppc405ex
• Description: Powerpc 405ex Embedded Processor
• Manufacturer: Applied Micro Circuits Corporation (AMCC)

PPC405EX – PowerPC 405EX Embedded Processor
Table 26. I/O Timing—DDR SDRAM Read Timing T
1. T
2. Clock speed for the values in the table is 200MHz.
3. The time values in the table include 1/4 of a cycle at 200MHz (5ns x 0.25 = 1.25 ns).
4. To obtain adjusted T
of the cycle time for the lower clock frequency (e.g., T
In the following example, the data strobes (DQS) and the data are shown to be coincident. There is actually a slight
skew as specified by the SDRAM specifications, and there can be additional skew due to loading and signal
routing. It is recommended that the signal length for all of the DQS signals be matched.
The following example shows the timing relationship between SDRAM DDR Data at the input pin and storing the
data in Stage 1.
AMCC Proprietary
MemData00:07
MemData08:15
MemData16:23
MemData24:31
ECC0:7
SD
and T
Signal Names
HD
are measured under worst case conditions.
SD
and T
HD
values for lower clock frequencies, subtract 0.75 ns from the values in the table and add 1/4
Reference Signal
DQS0
DQS1
DQS2
DQS3
DQS4
SD
- 1.25 + 0.25T
SD
and T
Read Data vs DQS Set up
HD
CYC
).
T
SD
0.27
0.27
0.27
0.27
0.27
(ns)
Preliminary Data Sheet
Revision 1.21 - July 9, 2008
Read Data vs DQS Hold
T
HD
0.45
0.45
0.45
0.45
0.45
(ns)
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