Altera DDR SDRAM High-Performance Controllers and ALTMEMP Bedienungsanleitung Seite 57

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Chapter 5: Functional Description—ALTMEMPHY 5–11
Block Description
June 2011 Altera Corporation External Memory Interface Handbook Volume 3
Section I. DDR and DDR2 SDRAM Controllers with ALTMEMPHY IP User Guide
PLL Reconfiguration
The ALTMEMPHY parameter editor automatically generates the PLL reconfiguration
block by instantiating an ALTPLL_RECONFIG variation for Stratix II and
Stratix II GX devices to match the generated ALTPLL megafunction instance. The
ALTPLL_RECONFIG megafunction varies the resynchronization clock phase and the
measure clock phase.
1 The ALTMEMPHY parameter editor does not instantiate an ALTPLL_RECONFIG
megafunction for Arria II GX devices, as this device uses the dedicated phase
stepping I/O on the PLL.
DLL
A DLL instance is included in the generated ALTMEMPHY variation. When using the
DQS to capture the DQ read data, the DLL center-aligns the DQS strobe to the DQ
data. The DLL settings depend on the interface clock frequency.
f For more information, refer to the External Memory Interfaces chapter in the device
handbook for your target device family.
Reset Management
The reset management block is responsible for the following:
Provides appropriately timed resets to the ALTMEMPHY megafunction datapaths
and functional modules
Performs the reset sequencing required for different clock domains
Provides reset management of PLL and PLL reconfiguration functions
Half-rate
and full
rate
measure_clk_2x
C5 Calibrated Full-Rate Global Regional
This clock is for VT
tracking. This
free-running clock
measures relative phase
shifts between the
internal clock(s) and
those being fed back
through a mimic path.
As a result, the
ALTMEMPHY
megafunction can track
VT effects on the FPGA
and compensate for the
effects.
Note to Table 5–2:
(1) In full-rate designs, a
_1x
clock may run at full-rate clock rate.
(2) The default clock network type is Global, however you can specify a regional clock network to improve clock jitter if your design uses any three
quadrants.
Table 5–2. DDR/DDR2 SDRAM Clocking in Arria II GX Devices (Part 3 of 3)
Design
Rate
Clock Name (1)
Postscale
Counter
Phase
(Degrees)
Clock
Rate
Clock Network Type
Notes
All
Quadrants
Any 3
Quadrants
(2)
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