Critical Issue
This problem affects DDR2 and DDR3, QDR II, and RLDRAM II products.
UniPHY designs targeting Stratix V ES devices may fail hold timing in the TimeQuest Timing Analyzer.
There are two classes of potential failures that could occur. If you observe one of the following problems, you may ignore the violation and attempt to run the design in hardware:
Failure class 1: Transfers from a dual-regional clock domain to a global clock domain may occur in UniPHY variants using the Nios II-based sequencer. A hold or removal violation of approximately 100ps or less might be observed on the following transfers:
- from clock "if0|_if0_p0_pll_avl_clock"
to clock "if0|_if0_p0_afi_clk"
- from clock "if0|_if0_p0_pll_config_clock"
to clock "if0|_if0_p0_afi_clk"
- from clock "if0|_if0_p0_pll_avl_clock"
to clock "if0|_if0_p0_pll_config_clock"
Failure class 2: A violation may be associated with core-to-periphery or periphery-to-core transfers. The following paragraphs illustrate examples for different protocols.
DDR2 full-rate
A hold violation of approximately 100ps or less might be observed on the following transfers:
- from clock "if0|_if0_p0_pll_afi_clk"
to clock "if0|_if0_p0_write_clk"
- from clock "if0|_if0_p0_pll_afi_clk"
to clock "if0|_if0_p0_dq_write_clk"
DDR3 quarter-rate
A hold violation of approximately 100ps or less might be observed on the following transfers:
- from clock "if0|_if0_p0_pll_afi_clk"
to clock "if0|_if0_p0_write_clk”
- from clock "if0|_if0_p0_pll_afi_clk"
to clock "if0|_if0_p0_p2c_read_clock”
- from clock "if0|_if0_p0_pll_hr_clk"
to clock "if0|_if0_p0_c2p_write_clock"
- from clock "if0|_if0_p0_pll_hr_clk"
to clock "if0|_if0_p0_p2c_read_clock"
- from clock "if0|_if0_p0_c2p_write_clock"
to clock "if0|_if0_p0_write_clk”
- from clock "if0|_if0_p0_p2c_read_clock"
to clock "if0|_if0_p0_pll_afi_clk"
- from clock "if0|_if0_p0_p2c_read_clock"
to clock "if0|_if0_p0_write_clk"
QDR II full-rate
A hold violation of approximately 100ps or less might be observed on the following transfers:
- from clock "if0|_if0_p0_pll_afi_clk"
to clock "if0|_if0_p0_leveling_clock_d_*"
- from clock "if0|_if0_p0_pll_afi_clk"
to clock "if0|_if0_p0_leveling_clock_k_*"
- from clock "if0|_if0_p0_pll_afi_clk"
to clock "if0|_if0_p0_leveling_clock_ac_*"
RLDRAM II full-rate
A hold violation of approximately 200ps or less might be observed on the following transfers:
- from clock "if0|_if0_p0_pll_afi_clk"
to clock "if0|_if0_p0_leveling_clock_dq_*"
- from clock "if0|_if0_p0_pll_afi_clk"
to clock "if0|_if0_p0_leveling_clock_ac_*"