constraints.txt

CNC 的开放码,EMC2 V2.2.8版

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#      BASIC UCF SYNTAX EXAMPLES V2.1.5      #
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#
#              TIMING SPECIFICATIONS
#
# Timing specifications can be applied to the entire device (global) or to
# specific groups of logic in your PLD design (called "time groups').
# The time groups are declared in two basic ways.
#
# Method 1: Based on a net name, where 'my_net' is a net that touchs all the
#           logic to be grouped in to 'logic_grp'. Example:
#NET my_net TNM_NET = logic_grp
#
# Method 2: Group uing the key word 'TIMEGRP' and declare using the names of
#           logic in your design. Example:
#TIMEGRP group_name = FFS ("U1/*")
#           creates a group called 'group_name' for all flip-flops with in
#           the hierarchical block called U1. Wildcards are valid.
#
# Grouping is very important because it lets you tell the software which parts
# of a design run at which speeds.  For the majority of the designs with only
# one clock the very simple global constraints.
#
# The type of grouping constraint you use can vary depending on the synthesis
# tools you are using.  For example, Synplicity does well with Method 1, while
# FPGA Express does beter with Method 2.
#
#
############################################################
# Internal to the device clock speed specifications - Tsys #
############################################################
#
# data      _________      /^^^^^\       _________   out
# ----------| D   Q |-----{ LOGIC } -----| D   Q |------
#           |       |      \vvvvv/       |       |
#        ---|> CLK  |                 ---|> CLK  |
# clock  |  ---------                 |  ---------
# ------------------------------------
#
# ---------------
# Single Clock
# ---------------
#
# ----------------
# PERIOD TIME-SPEC
# ----------------
# The PERIOD spec. covers all timing paths that start or end at a
# register, latch, or synchronous RAM which are clocked by the reference
# net (excluding pad destinations).  Also covered is the setup
# requirement of the synchronous element relative to other elements
# (ex. flip flops, pads, etc...).
# NOTE:  The default unit for time is nanoseconds.
#
#NET clock PERIOD = 50ns
#
#       -OR-
#
# ------------------
# FROM:TO TIME-SPECs
# ------------------
# FROM:TO style timespecs can be used to constrain paths between time
# groups.  NOTE:  Keywords:  RAMS, FFS, PADS, and LATCHES are predefined
# time groups used to specify all elements of each type in a design.
#TIMEGRP RFFS = RISING FFS ("*");  // creates a rising group called RFFS
#TIMEGRP FFFS = FALLING FFS ("*");  // creates a falling group called FFFS
#TIMESPEC TSF2F  = FROM : FFS   : TO : FFS   : 50 ns; // Flip-flips with the same edge
#TIMESPEC TSR2F  = FROM : RFFS  : TO : FFFS  : 25 ns; // rising edge to falling edge
#TIMESPEC TSF2R  = FROM : FFFS  : TO : RFFS  : 25 ns; // falling edge to rising edge
#
# ---------------
# Multiple Clocks
# ---------------
# Requires a combination of the 'Period' and 'FROM:TO' type time specifications
#NET clock1 TNM_NET = clk1_grp
#NET clock2 TNM_NET = clk2_grp
#
#TIMESPEC TS_clk1 = PERIOD : clk1_grp : 50
#TIMESPEC TS_clk2 = PERIOD : clk2_grp : 30
#TIMESPEC TS_ck1_2_ck2 = FROM : clk1_grp : TO : clk2_grp : 50
#TIMESPEC TS_ck2_2_ck1 = FROM : clk2_grp : TO : clk1_grp : 30
#
#
############################################################
# CLOCK TO OUT specifications - Tco                        #
############################################################
#
# from      _________      /^^^^^\       --------\
# ----------| D   Q |-----{ LOGIC } -----| Pad    >
# PLD       |       |      \vvvvv/       --------/
#        ---|> CLK  |
# clock  |  ---------
# --------
#
# ----------------
# OFFSET TIME-SPEC
# ----------------
# To automatically include clock buffer/routing delay in your
# clock-to-out timing specifications, use OFFSET constraints .
# For an output where the maximum clock-to-out (Tco) is 25 ns:
#NET out_net_name OFFSET = OUT 25 AFTER clock_net_name
#
#      -OR-
#
# ------------------
# FROM:TO TIME-SPECs
# ------------------
#TIMESPEC TSF2P  = FROM : FFS   : TO : PADS  : 25 ns
# Note that FROM: FFS : TO: PADS constraints start the delay analysis
# at the flip flop itself, and not the clock input pin.  The recommended
# method to create a clock-to-out constraint is to use an OFFSET constraint.
#
#
############################################################
# Pad to Flip-Flop speed specifications - Tsu              #
############################################################
#
# ------\         /^^^^^\       _________   into PLD
# |pad   >-------{ LOGIC } -----| D   Q |------
# ------/         \vvvvv/       |       |
#                            ---|> CLK  |
# clock                      |  ---------
# ----------------------------
#
# ----------------
# OFFSET TIME-SPEC
# ----------------
# To automatically account for clock delay in your input setup timing
# specifications, use OFFSET constraints.
# For an input where the maximum setup time is 25 ns:
#NET in_net_name OFFSET = IN 25 BEFORE clock_net_name
#
#      -OR-
#
# ------------------
# FROM:TO TIME-SPECs
# ------------------
#TIMESPEC TSP2F  = FROM : PADS  : TO : FFS   : 25 ns
# Note that FROM: PADS : TO: FFS constraints do not take into account any
# delay for the clock path.  The recommended method to create an input
# setup time constraint is to use an OFFSET constraint.
#
#
############################################################
# Pad to Pad speed specifications - Tpd                    #
############################################################
#
# ------\         /^^^^^\       -------\
# |pad   >-------{ LOGIC } -----| pad   >
# ------/         \vvvvv/       -------/
#
# ------------------
# FROM:TO TIME-SPECs
# ------------------
#TIMESPEC TSP2P  = FROM : PADS  : TO : PADS  : 125 ns
#
#
############################################################
# Other timing specifications                              #
############################################################
#
# -------------
# TIMING IGNORE
# -------------
# If you can ignore timing of paths, use Timing Ignore (TIG). NOTE: The
# "*" character is a wild-card which can be used for bus names.  A "?"
# character can be used to wild-card one character.
# Ignore timing of net reset_n:
#NET : reset_n : TIG
#
# Ignore data_reg(7:0) net in instance mux_mem:
#NET : mux_mem/data_reg* : TIG
#
# Ignore data_reg(7:0) net in instance mux_mem as related to a TIMESPEC
# named TS01 only:
#NET : mux_mem/data_reg* : TIG = TS01
#
# Ignore data1_sig and data2_sig nets:
#NET : data?_sig : TIG
#
# ---------------
# PATH EXCEPTIONS
# ---------------
# If your design has outputs that can be slower than others, you can
# create specific timespecs similar to this example for output nets
# named out_data(7:0) and irq_n:
#TIMEGRP slow_outs = PADS(out_data* : irq_n)
#TIMEGRP fast_outs = PADS : EXCEPT : slow_outs
#TIMESPEC TS08 = FROM : FFS : TO : fast_outs : 22
#TIMESPEC TS09 = FROM : FFS : TO : slow_outs : 75
#
# If you have multi-cycle FF to FF paths, you can create a time group
# using either the TIMEGRP or TNM statements.
#
# WARNING:  Many VHDL/verilog synthesizers do not predictably name flip
# flop Q output nets.  Most synthesizers do assign predictable instance
# names to flip flops, however.
#
# TIMEGRP example:
#TIMEGRP slowffs = FFS(inst_path/ff_q_output_net1* :
#inst_path/ff_q_output_net2*)
#
# TNM attached to instance example:
#INST inst_path/ff_instance_name1_reg* TNM = slowffs
#INST inst_path/ff_instance_name2_reg* TNM = slowffs
#
# If a FF clock-enable is used on all flip flops of a multi-cycle path,
# you can attach TNM to the clock enable net.  NOTE:  TNM attached to a
# net "forward traces" to any FF, LATCH, RAM, or PAD attached to the
# net.
#NET ff_clock_enable_net TNM = slowffs
#
# Example of using "slowffs" timegroup, in a FROM:TO timespec, with
# either of the three timegroup methods shown above:
#TIMESPEC TS10 = FROM : slowffs : TO : FFS : 100
#
# Constrain the skew or delay associate with a net.
#NET any_net_name MAXSKEW = 7
#NET any_net_name MAXDELAY = 20 ns
#
#
# Constraint priority in your .ucf file is as follows:
#
#    highest 1.  Timing Ignore (TIG)
#                 2.  FROM : THRU : TO specs
#             3.  FROM : TO specs
#    lowest  4.  PERIOD specs
#
# See the on-line "Library Reference Guide" document for
# additional timespec features and more information.
#
#
############################################################
#                                                          #
#         LOCATION and ATTRIBUTE SPECIFICATIONS            #
#                                                          #
############################################################
# Pin and CLB location locking constraints                 #
############################################################
#
# -----------------------
# Assign an IO pin number
# -----------------------
#INST io_buf_instance_name  LOC = P110
#NET io_net_name  LOC = P111
#
# -----------------------
# Assign a signal to a range of I/O pins
# -----------------------
#NET "signal_name" LOC=P32, P33, P34
#
# -----------------------
# Place a logic element(called a BEL) in a specific CLB location.  BEL = FF, LUT, RAM, etc...
# -----------------------
#INST instance_path/BEL_inst_name  LOC = CLB_R17C36
#
# -----------------------
# Place CLB in rectangular area from CLB R1C1 to CLB R5C7
# -----------------------
#INST /U1/U2/reg<0> LOC=clb_r1c1:clb_r5c7
#
# -----------------------
# Place Heirarchial logic block in rectangular area from CLB R1C1 to CLB R5C7
# -----------------------
#INST /U1* LOC=clb_r1c1:clb_r5c7
#
# -----------------------
# Prohibit IO pin P26 or CLBR5C3 from being used:
# -----------------------
#CONFIG PROHIBIT = P26
#CONFIG PROHIBIT = CLB_R5C3
# Config Prohibit is very important for frocing the software to not use critical
# configuration pins like INIT or DOUT on the FPGA.  The Mode pins and JTAG
# Pins require a special pad so they will not be availabe to this constraint
#
# -----------------------
# Assign an OBUF to be FAST or SLOW:
# -----------------------
#INST obuf_instance_name FAST
#INST obuf_instance_name SLOW
#
# -----------------------
# FPGAs only:  IOB input Flip-flop delay specifcation
# -----------------------
# Declare an IOB input FF delay (default = MAXDELAY).
# NOTE:  MEDDELAY/NODELAY can be attached to a CLB FF that is pushed
# into an IOB by the "map -pr i" option.
#INST input_ff_instance_name MEDDELAY
#INST input_ff_instance_name NODELAY
#
# -----------------------
# Assign Global Clock Buffers Lower Left Right Side
# -----------------------
# INST gbuf1 LOC=SSW
#