# # Copyright 2021 Ettus Research, a National Instruments Brand # # SPDX-License-Identifier: LGPL-3.0-or-later # # Description: # # Common timing constraints for the X4xx's motherboard CPLD. # set_time_format -unit ns -decimal_places 3 ##################################################################### # General ##################################################################### # For a couple of 3.3V interfaces the buffer SN74AVC4T774RSVR is used to # increase the drive strength. For reuse we define the timings constants here. # For direction A to B and B to A the maximum timing varies by 0.1 ns. Taking # the maximum of both. set buffer_prop_min 0.100 set buffer_prop_max 2.400 ##################################################################### # Main Clocks ##################################################################### ## Input clocks. # Reliable clock: 100.0 MHz set CLK_100_period 10.000 create_clock -name CLK_100 -period $CLK_100_period [get_ports CLK_100] # internal PLL derived clock derive_pll_clocks # provide name for derived clocks set CLK_250 [get_clocks {*clk[1]}] # PLL output pins of the generated 50 MHz clock for internal processing set clk50_period 20.000 set pll_clk_out_pin [get_pins {pll_inst|altpll_component|auto_generated|pll1|clk[0]}] set clk250_period 4.000 # PLL reference clock: 64 MHz (maximum) set prc_clock_period 15.625 create_clock -name PLL_REF_CLK -period $prc_clock_period [get_ports PLL_REF_CLK] ##################################################################### # Timing exceptions ##################################################################### ## SPI slaves # Delay path for all synchronizers is based on the period of the # faster clock domain (50 MHz derived by the PLL from 100 MHz reliable clock). set clk50_period [expr {$CLK_100_period * 2}] set_max_delay -to [get_registers *synchronizer_false_path\|value\[0\]\[*\]] \ $clk50_period # sclk data to CLK_100 set_max_delay -from [get_registers *spi_slave_async\|received_word\[*\]] \ -to [get_registers *spi_slave_async\|data_out\[*\]] \ $clk50_period # PLL driven data to sclk set_max_delay -from [get_clocks {pll_inst*}] \ -to [get_registers *spi_slave_async\|transmit_bits\[*\]] \ $clk50_period ##################################################################### # Power supply clocks, LEDs, DIO direction ##################################################################### # Change all output signals in this section within one clock period of the # driving clocks. # Power supply clocks set power_supply_clocks_outputs [get_ports {PWR_SUPPLY_CLK_*}] set_min_delay -to $power_supply_clocks_outputs 0 set_max_delay -to $power_supply_clocks_outputs $CLK_100_period # LED signals in db specific sdc # DIO direction set dio_outputs [get_ports {DIO_DIRECTION_A[*] DIO_DIRECTION_B[*]}] set_min_delay -to $dio_outputs 0 set_max_delay -to $dio_outputs $clk50_period # Power control set pwr_ctrl_outputs [get_ports {IPASS_POWER_DISABLE PWR_EN_5V_OSC_100 PWR_EN_5V_OSC_122_88}] set_min_delay -to $pwr_ctrl_outputs 0 set_max_delay -to $pwr_ctrl_outputs $clk50_period # Power fault inputs # Virtual clocks for constraining inputs. Using an odd clock period to # make sure any uncovered paths will result in timing errors due to short setup # or hold path. set power_fault_inputs [get_ports {IPASS_POWER_EN_FAULT[*]}] create_clock -name virtual_async_in_clk -period 4.567 set_input_delay -clock virtual_async_in_clk 0 $power_fault_inputs ##################################################################### # FPGA <-> MB CPLD PL SPI interface ##################################################################### # Create clock for the PL's SPI interface. # PRC at least divided by 2 by the SPI Master on FPGA set pl_sclk_period [expr {2 * $prc_clock_period}] create_clock -name pl_sclk -period $pl_sclk_period [get_registers mb_cpld_sclk] # The SPI PL master (on the FPGA) is designed as a system synchronous # interface using PLL_REF_CLK. # The FPGA output constraints are required to calculate the windows # at CPLD of valid data # They are derived iteratively from the FPGA design ensuring a large # valid data period. set pl_spi_fpga_min_out 0.000 set pl_spi_fpga_max_out 11.000 # The longest trace on the PL SPI interface is (sssuming 170.0 ps/in) # Longest trace | Trace length | Trace delay # CS_0 | 7.143 in | 1.215 ns set pl_spi_board_delay 1.215 # This path also contains a level translator which has a typical # switching time of 2.7 ns. Let's add a margin of 1 ns as worst # case estimation set pl_level_trans_delay 3.700 # CPLD and FPGA both use PLL reference clock from a common clock chip. # The traces from that clock chip to the ICs are not length matched # Assume a worst case clock difference of 0.5 ns at the IC inputs. # There is no direction defined. The clock can arrive faster or slower # on one IC. set pl_clock_diff 0.500 set pl_slave_inputs [get_ports {PL_CPLD_SCLK PL_CPLD_MOSI PL_CPLD_CS_N[*]}] # calculate output delays back from capturing edge, add board delay, level translator and clock difference set_input_delay -clock PLL_REF_CLK \ -max [expr {$prc_clock_period - $pl_spi_fpga_max_out + $pl_spi_board_delay + $pl_level_trans_delay + $pl_clock_diff}] \ $pl_slave_inputs # Assuming data is going without any delay, clock is arriving early at CPLD. # Negate minimum output delay as it is defined from the change to the start clock edge. set_input_delay -clock PLL_REF_CLK \ -min [expr {- $pl_spi_fpga_min_out - $pl_clock_diff}] \ $pl_slave_inputs # ensure large data valid window for the FPGA # those values are used in the FPGA / DB CPLDs # to calculate the input delay # those values are maximum integer values to still meet timing set pl_spi_cpld_min_out -1.000 set pl_spi_cpld_max_out 8.000 set pl_slave_outputs [get_ports {PL_CPLD_MISO}] set_output_delay -clock PLL_REF_CLK -max $pl_spi_cpld_max_out $pl_slave_outputs set_output_delay -clock PLL_REF_CLK -min $pl_spi_cpld_min_out $pl_slave_outputs ##################################################################### # FPGA <-> MB CPLD PS SPI interface ##################################################################### # Assume the PS SPI clock is maximum 5 MHz. # It is driven from another source and provided with the data. set ps_sclk_period 200.000 create_clock -name ps_sclk -period $ps_sclk_period [get_ports PS_CPLD_SCLK] # The SPI PS master (on the FPGA) is wired through the MIO (Multiplexed I/O) # pins, meaning that the timing characteristics of the interface come from # the controller itself (i.e. no timed routing through PL). # Based on the SPI master controller specification (DS925: Table 48), # one may define the min/max input/output delay constraints. set ps_spi_tco_min -2.000 set ps_spi_tco_max 5.000 set ps_spi_miso_setup -2.000 set ps_spi_miso_hold [expr {0.3 * $ps_sclk_period}] # Use the worst-case board propagation delays. # Assuming 170.0 ps/in. # Longest trace | Trace length | Trace delay # CS0_n | 4.735 in | 0.805 ns # -------------------------------------------- set ps_spi_board_delay 0.805 set ps_slave_inputs [get_ports {PS_CPLD_MOSI PS_CPLD_CS_N[*]}] # clock is immediately available, data is taking maximum time # SPI data in CPOL=CPHA=1 is driven on the falling sclk edge set ps_sclk_max_in_delay [expr {$ps_spi_tco_max + $ps_spi_board_delay}] set_input_delay -clock ps_sclk -clock_fall \ -max $ps_sclk_max_in_delay \ $ps_slave_inputs # fast data and clock delayed (reducing data delay) set_input_delay -clock ps_sclk -clock_fall \ -min [expr {$ps_spi_tco_min - $ps_spi_board_delay}] \ $ps_slave_inputs set ps_slave_outputs [get_ports {PS_CPLD_MISO}] # use only half the frequency because falling edge is driving data set_output_delay -clock ps_sclk \ -max [expr {$ps_spi_miso_setup + 2*$ps_spi_board_delay}] \ $ps_slave_outputs # use hold requirement only as clock and data propagation further # delay the signal set_output_delay -clock ps_sclk \ -min [expr {-$ps_spi_miso_hold}] \ $ps_slave_outputs # Chip select signals are captured for binary decoding in 250 MHz clock domain. # To be able to specify a maximum delay for the data path only a second set of # input delays is added to the root clock of the 250 MHz domain. set_input_delay -add_delay -clock CLK_100 0 [get_ports {PS_CPLD_CS_N[*]}] # Declare paths between the 2 clock domains as false paths set_false_path -from [get_clocks {CLK_100}] -to [get_ports {PS_CPLD_MISO}] set_false_path -from [get_clocks {ps_sclk}] -to [get_registers {synchronizer:ps_spi_input_sync_inst*}] # Specify maximum data path delay set_max_delay -from [get_ports {PS_CPLD_CS_N[*]}] -to $CLK_250 $clk250_period ##################################################################### # MB CPLD PS SPI passthrough common ##################################################################### ###### Binary CS decoding ###### # The CS outputs for the external SPI slaves are driven from a 250 MHz clock to # ensure glitch free switching after binary encoding. Additionally those signals # have to meet the setup and hold requirements of the SPI slaves operating at # ps_sclk (5 MHz). CS lines typically are asserted half a clock period of sclk # before any active edge of sclk. The constraints below are using multi-cycle # paths to provide the placer with information about the clock multiplier from # ps_sclk to 250 MHz. Furthermore they incorporate the time required for # decoding by lowering the clock multiplier as shown in the waveform below # (multiplier is not shown correctly). # # ps_sclk -\__________________________________________________/-------- # 250 MHz _/-\_/-\_/-\_/-\_/-\_/-\_/-\_/-\_/-\_/-\_/-\_/-\_/-\_/-\_/-\- # CS @ CPLD input X>--------------- stable ------------------------------------ # CS @ CPLD output ----------------------- stable --------------------- # |<----->| min decoding delay # |<----->| change window # --------------->| SPI slave hold requirement # SPI slave setup requirement |<-------------------------------->| # # Get port to apply the multi-cycle constraint. set binary_cs_ports [get_ports {LMK32_CS_N TPM_CS_N PHASE_DAC_CS_N CLK_DB_CS_N}] # Determine number of full 250 MHz periods within half a period of ps_sclk. set ps_spi_clock_divider [expr {int($ps_sclk_period/$clk250_period/2)}] # Setup multi-cycle accounts for # - one clock cycle data path delay from port to first register stage # - one clock cycle to resolve meta-stability # - up to 3 register stages internally (port to ps_cpld_cs_n_shift3) # - one output register stage (registers on each $binary_cs_ports) # Static timing analysis will take the data path from register to output port # into account. # The number of 250 MHz periods is reduced by a total of 7 clock cycles (listed # above) to match the SPI slave setup requirement time shown in the waveform # above. The slave's setup time in ps_sclk domain is specified below for each # individual slave. set ps_spi_setup_multicycle [expr {$ps_spi_clock_divider - 7}] set_multicycle_path -setup -start -to $binary_cs_ports $ps_spi_setup_multicycle # Hold multicycle accounts for # - min 2 synchronization register stages internally (ps_cpld_cs_n_shift2) # (= min one clock cycle delay as data could arrive just before setup # requirement of first register stages assuming no data delay) # - one output register stage # Static timing analysis will take the data path from register to output port # into account. # As the clock edge for hold analysis is shifted with the setup edge the number # of multi cycles has to be increased by this amount of cycles to get back to # the falling edge of ps_sclk. Furthermore CS lines are released one half # ps_sclk period after the last data transfer. So hold delay is increased by an # additional half clock cycle. set ps_spi_hold_multicycle [expr {$ps_spi_clock_divider + $ps_spi_setup_multicycle - 2}] set_multicycle_path -hold -start -to $binary_cs_ports $ps_spi_hold_multicycle ###### local SPI slave ###### # The chip select path for the MB CPLD itself is driven in the 250 MHz clock # domain and captured by registers operating at ps_sclk. Therefore setting the # path as false path preventing the placer from adding additional routing delay # to ensure hold timing. The setup path is limited to a maximum extend of one # clock period. As this path crosses clock domains clock propagation is included # in this path during static timing analysis. The TCL analysis in # scripts/ps_cs_analysis.tcl ensures a maximum value for data excluding the # clocking network. set_false_path -from [get_registers {ps_spi_cs_n_decoded[0]}] -hold set_max_delay -from [get_registers {ps_spi_cs_n_decoded[0]}] $clk250_period ###### LMK04832 ###### create_generated_clock -source [get_ports PS_CPLD_SCLK] \ -name lmk_spi_sclk [get_ports LMK32_SCLK] # Use the worst-case board propagation delays. # Assuming 170.0 ps/in. # Longest trace | Trace length | Trace delay # LMK32_SCLK | 8.259 in | 1.404 ns # -------------------------------------------- set lmk_board_delay 1.404 # setup and hold dominated by CS <-> SCK relationship set lmk_setup 20.000 set lmk_hold 20.000 set lmk_tco_max 60.000 set lmk_outputs [get_ports {LMK32_MOSI LMK32_CS_N}] set_output_delay -clock lmk_spi_sclk \ -max [expr {$lmk_setup + $lmk_board_delay + $buffer_prop_max}] \ $lmk_outputs set_output_delay -clock lmk_spi_sclk \ -min [expr {-$lmk_hold - $lmk_board_delay - $buffer_prop_min}] \ $lmk_outputs set lmk_inputs [get_ports {LMK32_MISO}] set_input_delay -clock lmk_spi_sclk -clock_fall \ -max [expr {$lmk_tco_max + 2*$lmk_board_delay + 2*$buffer_prop_max}] \ $lmk_inputs set_input_delay -clock lmk_spi_sclk -clock_fall \ -min [expr {2*$buffer_prop_min}] \ $lmk_inputs ###### Phase DAC ###### create_generated_clock -source [get_ports PS_CPLD_SCLK] \ -name phase_dac_spi_sclk [get_ports PHASE_DAC_SCLK] # Use the worst-case board propagation delays. # Assuming 170.0 ps/in. # Longest trace | Trace length | Trace delay # SpiDCs3v3_n | 8.322 in | 1.415 ns # -------------------------------------------- set phase_dac_board_delay 1.415 #setup dominated by SYNC signal set phase_dac_setup 13.000 set phase_dac_hold 5.000 # device captures data on falling clock edge (CPOL = 1) # constraining it as it would be like all the other SPI modules # PS SPI master is responsible for changing SPI mode when talking # to this device set phase_dac_outputs [get_ports {PHASE_DAC_MOSI PHASE_DAC_CS_N}] set_output_delay -clock phase_dac_spi_sclk -clock_fall \ -max [expr {$phase_dac_setup + $phase_dac_board_delay}] \ $phase_dac_outputs set_output_delay -clock phase_dac_spi_sclk -clock_fall \ -min [expr {-$phase_dac_hold - $phase_dac_board_delay}] \ $phase_dac_outputs ###### TPM ###### create_generated_clock -source [get_ports PS_CPLD_SCLK] \ -name tpm_spi_sclk [get_ports TPM_SCLK] # Use the worst-case board propagation delays. # Assuming 170.0 ps/in. # Longest trace | Trace length | Trace delay # TPM_CS_n | 1.128 in | 0.196 ns # -------------------------------------------- set tpm_board_delay 0.196 #tco dominated by NSS signal set tpm_setup 5.000 set tpm_hold 5.000 set tpm_tco_max 25.000 set tpm_outputs [get_ports {TPM_MOSI TPM_CS_N}] set_output_delay -clock tpm_spi_sclk \ -max [expr {$tpm_setup + $tpm_board_delay}] \ $tpm_outputs set_output_delay -clock tpm_spi_sclk \ -min [expr {-$tpm_hold - $tpm_board_delay}] \ $tpm_outputs set tpm_inputs [get_ports {TPM_MISO}] set_input_delay -clock tpm_spi_sclk -clock_fall \ -max [expr {$tpm_tco_max + 2*$tpm_board_delay}] \ $tpm_inputs set_input_delay -clock tpm_spi_sclk -clock_fall \ -min 0 \ $tpm_inputs #### Clocking AUX board SPI interface #### # Rev B clocking aux board uses a LMK05318 connected to this interface # Using its timing for this interface. create_generated_clock -source [get_ports PS_CPLD_SCLK] \ -name clk_db_clk_out [get_ports CLK_DB_SCLK] set clk_db_setup 10.000 set clk_db_hold 10.000 set clk_db_tco_max 20.000 # Just a worst case assumption based on 2 times the MB trace length CLK_DB_MOSI. # The multiplier 2 accounts for any traces on the CLK AUX board. set clk_db_board_delay 4.000 set clk_db_outputs [get_ports {CLK_DB_CS_N CLK_DB_MOSI}] # Output signals have to stable for max setup and propagation time. Clock delay # to device is expected to be 0 in this equation. set_output_delay -clock clk_db_clk_out \ -max [expr {$clk_db_setup + $clk_db_board_delay + $buffer_prop_max}] $clk_db_outputs # The min output delay is comprised of: # - device required hold time ($clk_db_hold) # - max clock propagation delay ($clk_db_board_delay) # - min data propagation time (0) # All terms have to be negated as min output delay is defined in opposite # direction (positive into the past). set_output_delay -clock clk_db_clk_out \ -min [expr {-$clk_db_hold - $clk_db_board_delay - $buffer_prop_min}] $clk_db_outputs set clk_db_inputs [get_ports {CLK_DB_MISO}] # Max delay calculated is based on # - max clock delay ($clk_db_board_delay) # - max clock to out LMK ($clk_db_tco_max) # - max data path delay ($clk_db_board_delay) set_input_delay -clock clk_db_clk_out -clock_fall \ -max [expr {$clk_db_tco_max + $clk_db_board_delay*2 + 2*$buffer_prop_max}] $clk_db_inputs # Min delay assumes clock propagates to device and data propagates to CPLD # without any delays. set_input_delay -clock clk_db_clk_out -clock_fall \ -min [expr {2*$buffer_prop_min}] $clk_db_inputs ##################################################################### # PCIe signals ##################################################################### # I²C bus is operated at 100kHz. Constraints would not improve timing # significantly (typically in the order of nanoseconds, which is negligible # given the SCL period of 10 us). # PCI-Express reset signal is not timing critical as it is received # asynchronously by the FPGA. set_false_path -to [get_ports {IPASS_SDA[0] IPASS_SCL[0] PCIE_RESET}] # I²C inputs are only consumed by synchronizers. # Add exceptions for all known consumers. set_false_path -to [get_registers {PcieCmiWrapper:pcie_cmi_inst|PcieCmi:PcieCmix|UsfCablePort:UsfCablePortx|CablePort:CablePortx|I2cTop:CableI2cx|I2cMonitor:I2cMonitorx|I2cFilter:I2cFilterx|I2cSigFilter:SclFilterx|fSig_ms}] set_false_path -to [get_registers {PcieCmiWrapper:pcie_cmi_inst|PcieCmi:PcieCmix|UsfCablePort:UsfCablePortx|CablePort:CablePortx|I2cTop:CableI2cx|I2cMonitor:I2cMonitorx|I2cFilter:I2cFilterx|I2cSigFilter:SdaFilterx|fSig_ms}] set_false_path -to [get_registers {PcieCmiWrapper:pcie_cmi_inst|PcieCmi:PcieCmix|UsfCablePort:UsfCablePortx|CablePort:CablePortx|StuckBusFixer:StuckBusFixerx|DoubleSyncSlAsyncIn:DoubleSclkx|DoubleSyncAsyncInBase:DoubleSyncAsyncInBasex|DFlopAsync:oSig_msx|lpm_ff:LPM_FFx|dffs[0]}] set_false_path -to [get_registers {PcieCmiWrapper:pcie_cmi_inst|PcieCmi:PcieCmix|UsfCablePort:UsfCablePortx|CablePort:CablePortx|StuckBusFixer:StuckBusFixerx|DoubleSyncSlAsyncIn:DoubleSdax|DoubleSyncAsyncInBase:DoubleSyncAsyncInBasex|DFlopAsync:oSig_msx|lpm_ff:LPM_FFx|dffs[0]}] ##################################################################### # Known Issue of On-Chip Flash ##################################################################### # see https://www.intel.com/content/www/us/en/programmable/support/support-resources/knowledge-base/tools/2016/warning--332060---node---alteraonchipflash-onchipflash-alteraonc.html create_generated_clock -name flash_se_neg_reg \ -source [get_pins { on_chip_flash:flash_inst|altera_onchip_flash:onchip_flash_0|altera_onchip_flash_avmm_data_controller:avmm_data_controller|flash_se_neg_reg|clk }] \ -divide_by 2 [get_pins { on_chip_flash:flash_inst|altera_onchip_flash:onchip_flash_0|altera_onchip_flash_avmm_data_controller:avmm_data_controller|flash_se_neg_reg|q } ] ##################################################################### # Clock uncertainty ##################################################################### # Assign some uncertainty to all clocks set clock_uncertainty 0.150 set_clock_uncertainty -to [get_clocks *] $clock_uncertainty derive_clock_uncertainty