mirror of
https://github.com/marqs85/ossc.git
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45b093d768
From the Cyclone IV device handbook: > When you use the VREF pin as a regular input or output, you can expect > a reduced performance of toggle rate and tCO because of higher pin > capacitance. Previously, we had set all HDMI_TX pins to fast output, but doing so produces some worrying timing violations which were masked over by relaxation of the SDC constraints. With fast output enabled, actually fixing the timing constraints would require substantial RTL optimization. Instead, by only setting fast output on the VREF pins, I'm able to avoid the glitching that would occur without any fast output pins when displaying high clock rate line3x output, while also allowing fitter enough flexibility to avoid timing violations. In addition, this commit restores the previously relaxed HDMI_TX timing constraints to those documented in the IT6613 datasheet.
105 lines
6.8 KiB
Tcl
105 lines
6.8 KiB
Tcl
### CPU clock constraints ###
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create_clock -period 27MHz -name clk27 [get_ports clk27]
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set_input_delay -clock clk27 0 [get_ports {sda scl SD_CMD SD_DAT* *ALTERA_DATA0}]
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set_false_path -from [get_ports {btn* ir_rx HDMI_TX_INT_N HDMI_TX_MODE}]
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set_false_path -to {sys:sys_inst|sys_pio_1:pio_1|readdata*}
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### Scanconverter clock constraints ###
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create_clock -period 108MHz -name pclk_1x [get_ports PCLK_in]
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create_clock -period 54MHz -name pclk_2x_source [get_ports PCLK_in] -add
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create_clock -period 54MHz -name pclk_3x_source [get_ports PCLK_in] -add
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create_clock -period 33MHz -name pclk_4x_source [get_ports PCLK_in] -add
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create_clock -period 33MHz -name pclk_5x_source [get_ports PCLK_in] -add
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#derive_pll_clocks
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create_generated_clock -name pclk_2x -master_clock pclk_2x_source -source {scanconverter_inst|pll_pclk|altpll_component|auto_generated|pll1|inclk[1]} -multiply_by 2 -duty_cycle 50.00 {scanconverter_inst|pll_pclk|altpll_component|auto_generated|pll1|clk[0]} -add
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create_generated_clock -name pclk_3x -master_clock pclk_3x_source -source {scanconverter_inst|pll_pclk|altpll_component|auto_generated|pll1|inclk[1]} -multiply_by 3 -duty_cycle 50.00 {scanconverter_inst|pll_pclk|altpll_component|auto_generated|pll1|clk[0]} -add
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create_generated_clock -name pclk_4x -master_clock pclk_4x_source -source {scanconverter_inst|pll_pclk|altpll_component|auto_generated|pll1|inclk[1]} -multiply_by 4 -duty_cycle 50.00 {scanconverter_inst|pll_pclk|altpll_component|auto_generated|pll1|clk[1]} -add
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create_generated_clock -name pclk_5x -master_clock pclk_5x_source -source {scanconverter_inst|pll_pclk|altpll_component|auto_generated|pll1|inclk[1]} -multiply_by 5 -duty_cycle 50.00 {scanconverter_inst|pll_pclk|altpll_component|auto_generated|pll1|clk[1]} -add
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create_generated_clock -name pclk_27mhz -master_clock clk27 -source {scanconverter_inst|pll_pclk|altpll_component|auto_generated|pll1|inclk[0]} -multiply_by 1 -duty_cycle 50.00 {scanconverter_inst|pll_pclk|altpll_component|auto_generated|pll1|clk[0]} -add
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# retrieve post-mapping clkmux output pin
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set clkmux_output [get_pins scanconverter_inst|clkctrl1|outclk]
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# specify postmux clocks which clock postprocess pipeline
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create_generated_clock -name pclk_1x_postmux -master_clock pclk_1x -source [get_pins scanconverter_inst|clkctrl1|inclk[0]] -multiply_by 1 $clkmux_output
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create_generated_clock -name pclk_2x_postmux -master_clock pclk_2x -source [get_pins scanconverter_inst|clkctrl1|inclk[2]] -multiply_by 1 $clkmux_output -add
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create_generated_clock -name pclk_3x_postmux -master_clock pclk_3x -source [get_pins scanconverter_inst|clkctrl1|inclk[2]] -multiply_by 1 $clkmux_output -add
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create_generated_clock -name pclk_4x_postmux -master_clock pclk_4x -source [get_pins scanconverter_inst|clkctrl1|inclk[3]] -multiply_by 1 $clkmux_output -add
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create_generated_clock -name pclk_5x_postmux -master_clock pclk_5x -source [get_pins scanconverter_inst|clkctrl1|inclk[3]] -multiply_by 1 $clkmux_output -add
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create_generated_clock -name pclk_27mhz_postmux -master_clock pclk_27mhz -source [get_pins scanconverter_inst|clkctrl1|inclk[2]] -multiply_by 1 $clkmux_output -add
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# specify output clocks that drive PCLK output pin
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set pclk_out_port [get_ports HDMI_TX_PCLK]
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create_generated_clock -name pclk_1x_out -master_clock pclk_1x_postmux -source $clkmux_output -multiply_by 1 $pclk_out_port
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create_generated_clock -name pclk_2x_out -master_clock pclk_2x_postmux -source $clkmux_output -multiply_by 1 $pclk_out_port -add
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create_generated_clock -name pclk_3x_out -master_clock pclk_3x_postmux -source $clkmux_output -multiply_by 1 $pclk_out_port -add
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create_generated_clock -name pclk_4x_out -master_clock pclk_4x_postmux -source $clkmux_output -multiply_by 1 $pclk_out_port -add
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create_generated_clock -name pclk_5x_out -master_clock pclk_5x_postmux -source $clkmux_output -multiply_by 1 $pclk_out_port -add
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create_generated_clock -name pclk_27mhz_out -master_clock pclk_27mhz_postmux -source $clkmux_output -multiply_by 1 $pclk_out_port -add
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derive_clock_uncertainty
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# input delay constraints
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set TVP_dmin 0
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set TVP_dmax 1.5
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set critinputs [get_ports {R_in* G_in* B_in* HSYNC_in VSYNC_in FID_in}]
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foreach_in_collection c [get_clocks "pclk_1x pclk_*_source"] {
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set_input_delay -clock $c -min $TVP_dmin $critinputs -add_delay
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set_input_delay -clock $c -max $TVP_dmax $critinputs -add_delay
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}
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# output delay constraints as documented in the IT6613 datasheet
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# -- increased IT_Tsu from 1.0 to 1.5 due to #52
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set IT_Tsu 1.5
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set IT_Th -0.5
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set critoutputs_hdmi [get_ports {HDMI_TX_RD* HDMI_TX_GD* HDMI_TX_BD* HDMI_TX_DE HDMI_TX_HS HDMI_TX_VS}]
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foreach_in_collection c [get_clocks pclk_*_out] {
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set_output_delay -clock $c -min $IT_Th $critoutputs_hdmi -add
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set_output_delay -clock $c -max $IT_Tsu $critoutputs_hdmi -add
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}
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set_false_path -to [remove_from_collection [all_outputs] $critoutputs_hdmi]
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### CPU/scanconverter clock relations ###
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# Treat CPU clock asynchronous to pixel clocks
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set_clock_groups -asynchronous -group \
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{clk27 pclk_27mhz pclk_27mhz_postmux pclk_27mhz_out} \
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{pclk_1x pclk_1x_postmux pclk_1x_out} \
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{pclk_2x_source pclk_2x pclk_2x_postmux pclk_2x_out} \
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{pclk_3x_source pclk_3x pclk_3x_postmux pclk_3x_out} \
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{pclk_4x_source pclk_4x pclk_4x_postmux pclk_4x_out} \
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{pclk_5x_source pclk_5x pclk_5x_postmux pclk_5x_out}
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# Ignore paths from registers which are updated only at leading edge of vsync
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set_false_path -from [get_registers {scanconverter_inst|H_* scanconverter_inst|V_* scanconverter_inst|X_* scanconverter_inst|SL_* scanconverter_inst|LT_POS_*}]
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# Ignore paths from registers which are updated only at leading edge of hsync
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#set_false_path -from [get_registers {scanconverter:scanconverter_inst|line_idx scanconverter:scanconverter_inst|line_out_idx* scanconverter:scanconverter_inst|hmax*}]
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# Ignore paths that cross clock domains from 3x to 2x and 5x to 4x, since they share a clock line, but cannot co-occur.
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set_false_path -from [get_clocks {pclk_3x*}] -to [get_registers {scanconverter:scanconverter_inst|*_2x*}]
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set_false_path -from [get_clocks {pclk_5x*}] -to [get_registers {scanconverter:scanconverter_inst|*_4x*}]
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# Ignore paths to latency tester sync regs
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set_false_path -to [get_registers {lat_tester:lt0|mode_synced* lat_tester:lt0|VSYNC_in_* lat_tester:lt0|trigger_*}]
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### JTAG Signal Constraints ###
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#constrain the TCK port
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#create_clock -name tck -period "10MHz" [get_ports altera_reserved_tck]
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#cut all paths to and from tck
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set_clock_groups -exclusive -group [get_clocks altera_reserved_tck]
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#constrain the TDI port
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set_input_delay -clock altera_reserved_tck 20 [get_ports altera_reserved_tdi]
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#constrain the TMS port
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set_input_delay -clock altera_reserved_tck 20 [get_ports altera_reserved_tms]
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#constrain the TDO port
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#set_output_delay -clock altera_reserved_tck 20 [get_ports altera_reserved_tdo]
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