MCDMA/PCIe - what is frequency of coreclkout_hip?
Hello,
In the user guide, with H-tile types - Gen3x8, application clock or coreclkout_hip frequency = 250 MHz. But I could not verify it in the TA clock report.
Instead, I could see
"dut|dut|hip|altera_pcie_s10_hip_ast_pipen1b_inst|altera_pcie_s10_hip_ast_pllnphy_inst|g_phy_g3x8.phy_g3x8|phy_g3x8|xcvr_hip_native|ch0"
and its frequency is 500 MHz.
It matches the constraints below:
set clk_source_freq "250.0 MHz" set datarate_100m 80 ... # 500M for aibx2 clocks if BW less or equal 64G } elseif { [expr $datarate_100m * 8] <= 640 } { dict set multiply_factor_dict aib_internal_div 2 dict set divide_factor_dict aib_internal_div 1 dict set multiply_factor_dict clkout 1 dict set divide_factor_dict clkout 1 } ... create_generated_clock \ -name $inst|xcvr_hip_native|ch${channels} \ -source $no_inst_tx_internal_div_reg \ -master_clock $tx_internal_div_reg_name \ -multiply_by [dict get $multiply_factor_dict clkout] \ -divide_by [dict get $divide_factor_dict clkout] \ $no_inst_tx_clkout -add
I think this clock is transport-layer clock and it is used to derive application clock/ coreclkout_hip / pld_clk250 as in the code below
assign coreclkout_hip = enable_512adapter_hwtcl? pld_clk250 : coreclkout_hip_wire ; ... altera_ep_g3x16_avst512_io_pll_s10 altera_avst512_iopll ( .outclk_0 (pld_clk250), .refclk (coreclkout_hip_wire), .rst (~pin_perst), .locked (iopll_locked), .permit_cal (serdes_pll_locked_wire) );
Do I understand it correctly?
If it is correct, then, it is confusing to me. Here is what I found.
I use application clock / coreclkout_hip as the refclk of PLL to derive another clock domain (200 MHz). The setting of PLL is
- Reference clock = 250 MHz
- Output clock = 200 MHz
However, when re-check the TA clock report:
- Reference clock = 500 MHz
- Output clock = 400 MHz
what is wrong here?
My platform is Stratix 10 MX | Quartus Prime Pro ver 22.2
Thank you,
TN
Hi,
I think that indicates the Clock Fmax.
If you changed the optimization Mode from Balanced to Aggressive Area you can achieve the 500MHz.The Fmax specification is based on the fast clock used for serial data.
The interface Fmax is also dependent on the parallel clock domain which is design dependent and requires timing analysis.
Hope this clarified.Regards,
Wincent_Intel