ppc440spe Applied Micro Circuits Corporation (AMCC), ppc440spe Datasheet - Page 70

• Manufacturer Part Number: ppc440spe
• Description: Powerpc 440spe Embedded Processor
• Manufacturer: Applied Micro Circuits Corporation (AMCC)

PowerPC 440SPe Embedded Processor
DDR SDRAM I/O Specifications
The DDR SDRAM controller times its operation with internal PLB clock signals and generates MemClkOut0 from
the PLB clock. The PLB clock is an internal signal that cannot be directly observed. However MemClkOut0 is the
same frequency as the PLB clock signal and is in phase with the PLB clock signal.
Note: MemClkOut0 can be advanced with respect to the PLB clock by means of the SDRAM0_CLKTR
In the following sections, the label MemClkOut0(0) refers to MemClkOut0 when it has not been phase-shifted, and
MemClkOut0(90) refers to MemClkOut0 when it has been phase-advanced 90q. Advancing MemClkOut0 by 90q
creates a 3/4 cycle setup time and 1/4 cycle hold time for the address and control signals in relation to
MemClkOut0(90). The rising edge of MemClkOut0(90) aligns with the first rising edge of the DQS signal.
The following DDR data is generated by means of simulation and includes logic, driver, package RLC, and lengths.
It is not to be used as a circuit design recommendation. Values are calculated over best case and worst case
processes with speed, temperature, and voltage as follows:
Best Case = Fast process, 0°C, +1 .6V
Worst Case = Slow process, +95°C, +1.4 V
Note: In all the following DDR tables and timing diagrams, minimum values are measured under best case
conditions and maximum values are measured under worst case conditions.
The signals are terminated as indicated in the figure below for the DDR timing data in the following sections.
Figure 7. DDR SDRAM Signal Termination
70
PPC440SPe
Note: This diagram illustrates the model of the DDR SDRAM interface used when generating simulation timing data.
It is not a recommended physical circuit design for this interface. An actual interface design will depend on many
factors, including the type of memory used and the board layout.
programming register. In a typical system, users advance MemClkOut by 90q. This depends on the specific
application and requires a thorough understanding of the memory system in general (refer to the DDR
SDRAM controller chapter in the PPC440SPe Embedded Processor User’s Manual).
Addr/Ctrl/Data/DQS
MemClkOut0
MemClkOut0
10pF
10pF
V
120:
TT
50:
30pF
= SV
Preliminary Data Sheet
DD
/2
Revision 1.23 - Sept 21, 2006
AMCC Proprietary