Critical Issue
In the Quartus II software release version 14.1, the TimeQuest Timing Analyzer reports a minimum pulse width violation with the serial clock output of a PLL.
For the PCI Express (PCIe) IP core, the TimeQuest Timing Analyzer reports the pulse width violations along the path from the transmit (TX) serial clock outputs advanced transmit (ATX) PLL and clock multiplier unit (CMU) fractional phase-locked loop (fPLL) to various destinations in the high-speed serial interface (HSSI) TX physical medium attachment (PMA) channels. An example is shown below:
; Summary of Paths
; Slack ; Actual Width ; Required Width ; Type ; Clock ; Clock Edge ; Target ;
; -0.142 ; -0.142 ; 0.000 ; Low Pulse Width ; dut|pll_serial_clk_8g ; Rise ; dut|altpcie_a10_hip_pipen1b|g_xcvr.altpcie_a10_hip_pllnphy|g_xcvr.g_phy_g3x1.phy_g3x1|phy_g3x1|g_xcvr_native_insts[0].twentynm_xcvr_native_inst|twentynm_xcvr_native_inst|inst_twentynm_pma|gen_twentynm_hssi_pma_tx_buf.inst_twentynm_hssi_pma_tx_buf|clk0_tx ;
; -0.142 ; -0.142 ; 0.000 ; Low Pulse Width ; dut|pll_serial_clk_8g ; Rise ; dut|altpcie_a10_hip_pipen1b|g_xcvr.altpcie_a10_hip_pllnphy|g_xcvr.g_phy_g3x1.phy_g3x1|phy_g3x1|g_xcvr_native_insts[0].twentynm_xcvr_native_inst|twentynm_xcvr_native_inst|inst_twentynm_pma|gen_twentynm_hssi_pma_tx_cgb.inst_twentynm_hssi_pma_tx_cgb|cpulse_out_bus[0] ;
; -0.142 ; -0.142 ; 0.000 ; Low Pulse Width ; dut|pll_serial_clk_8g ; Rise ; dut|altpcie_a10_hip_pipen1b|g_xcvr.altpcie_a10_hip_pllnphy|g_xcvr.g_phy_g3x1.phy_g3x1|phy_g3x1|g_xcvr_native_insts[0].twentynm_xcvr_native_inst|twentynm_xcvr_native_inst|inst_twentynm_pma|gen_twentynm_hssi_pma_tx_cgb.inst_twentynm_hssi_pma_tx_cgb|hifreqclkp ;
; -0.141 ; -0.141 ; 0.000 ; Low Pulse Width ; dut|pll_serial_clk_8g ; Rise ; dut|altpcie_a10_hip_pipen1b|g_xcvr.altpcie_a10_hip_pllnphy|g_xcvr.g_phy_g3x1.phy_g3x1|phy_g3x1|g_xcvr_native_insts[0].twentynm_xcvr_native_inst|twentynm_xcvr_native_inst|inst_twentynm_pma|gen_twentynm_hssi_pma_tx_buf.inst_twentynm_hssi_pma_tx_buf|ckp ;
; -0.141 ; -0.141 ; 0.000 ; Low Pulse Width ; dut|pll_serial_clk_8g ; Rise ; dut|altpcie_a10_hip_pipen1b|g_xcvr.altpcie_a10_hip_pllnphy|g_xcvr.g_phy_g3x1.phy_g3x1|phy_g3x1|g_xcvr_native_insts[0].twentynm_xcvr_native_inst|twentynm_xcvr_native_inst|inst_twentynm_pma|gen_twentynm_hssi_pma_tx_cgb.inst_twentynm_hssi_pma_tx_cgb|ckdccp ;
...
This issue is fixed in the Quartus II software version 15.0. There is no workaround for previous software releases.