Logntk Commands
1. LOGNTK diagrams often contain additional commands in the form of
labels. These labels are always surrounded by "<" and ">" brackets.
Any labels of this form, but with commands that LOGNTK cannot
recognize, are simply ignored. LOGNTK assumes these commands belong
to some other program, such as Digital LOG's hierarchy compiler.
2. You can also include these commands in your "log.cnf" file,
preceded by "logntk:". For example, the label < global clock* >
defines global signals just for one cell; the CNF command
"logntk: global clock*" defines global signals permanently.
Finally, you could also press the ":" and type the
"logntk: global clock*" command during your LOG session.
3. Certain arguments may include wildcard characters. LOGNTK uses the
same kinds of wildcards as Unix: "?" matches any character, "*"
matches any zero or more characters, and "[ABC]" matches either
A, B, or C. Also, most names in LOGNTK are case-insensitive, but
LOGNTK still strives to duplicate the upper/lower-casing that you
use into the output file, and always capitalizes all the uses of a
name consistently.
4. Every LOGNTK definition needs at least some commands. To create a
named cell, you need a NAME command (or a quoted label; see below),
and either a PORT command or a template gate. For an unnamed
top-level cell, you need at least a FILE command.
5. Here is the list of LOGNTK commands. The ":" following the command
names are optional.
GLOBAL: signal-names
This command lists names which should be "global" to
the entire project. For example, VDD and GND are made
global by the standard "logntk.cnf" file.
This means that if you create a cell which includes
VDD and GND gates, those nodes will automatically be
made into "hidden" ports on the cell. Instances of
that cell will gate VDD and GND wired to them
automatically. All you have to do is used VDD and GND
naturally, and let the system keep track of it for you.
You can declare your own TO/FROM signal names to be
global in the same way. The "signal-names" are case-
insensitive, and may include wildcard characters.
PORT: signal-names
This command gives the list of ports in the cell. It
may be used in place of a "template" or "example" gate.
Port lists are supported for historical compatibility,
but future designs should probably use template gates
instead.
Each name in the list should correspond to a signal name
in the circuit diagram. VDD and GND refer to the VDD and
GND circuit symbols. The position of a name in the port
list, not counting global names, corresponds to the pin
number of the associated instance gate. For example, if
the .GATE picture for an inverter has the input as pin 1
and the output as pin 2, then the appropriate command for
the inverter's circuit diagram would be:
< port: in out vdd gnd > or
< port: gnd vdd in out > or whatever.
The positioning and ordering of global names in the list
is irrelevant, but any global signal that is used by the
cell or by its sub-cells must be present. (When you use
a template gate instead of a port list, LOGNTK manages
all this for you.) If you give a ":LOGNTK" command and
their is neither a port label nor a template gate in the
definition, LOGNTK will sort the signal names into
alphabetic order and create a PORT label. You will
probably need to edit this command to put the ports in
the proper order.
If several PORT labels appear in the cell definition,
they are appended together in an undefined order. If
you don't mind this uncertainty, LOGNTK can handle an
unlimited number of ports.
ORPHAN: gate-names
This command gives the gate(s) which are used to
represent "orphan" nodes, i.e., nodes that are not
connected to any transistors or subcells. By default,
the built-in gate CIRC1 is considered an orphan gate, so
that a circuit with five CIRC1's will have five orphan
nodes in its NTK file. The gate-names may use wildcards.
IGNORE: gate-names
This command gives a list of gates to be ignored. This
is rarely necessary, because if LOGNTK sees a gate which
has not been defined as a transistor or cell, and for
which no "gatename.NTK" file exists, then it will
automatically ignore that gate with a warning message.
This command suppresses the warning. The gate-names
may include wildcards.
NAME: cell-name
This specifies the name of the cell in the NTK file.
This is an alternate form for the quoted "cell-name"
label. There must be exactly one such label for each
cell.
FILE: file-name
This specifies the name of the output file. The suffix
".NTK" will be added if necessary. If you omit the FILE
command, the file name will be taken from the cell name.
(Every LOGNTK page must specify either a cell name or
a file name, or both.)
CELL: gate-name cell-name file-name
This command links gates in the circuit diagram
to the NTK files they represent. A good idea is
to use the same name for the gate, cell, and file;
if you give only one name in the command, that
name will be used for all three. One time you
might need to give the long form is if the NTK
file is not in the standard directories, so you
need to give a full path for it:
< cell: opamp tc_amp /lib/wollib/stdlib/opamp >
In this example, OPAMP gates, or generic instance
gates programmed as OPAMP's, will convert to calls
to the cell TC_AMP, which may be found in the .NTK
file specified. CELL commands describing cells that
are never instantiated in a file are ignored.
LIB: directories
This command names directories in which .NTK files
for sub-cells may be found. LOGNTK looks first in
the current directory, then in each of these
directories in turn.
SIZE: number
This specifies the sizes of nodes. Currently,
there is no way to override this for particular
nodes. The default size of 1 should be sufficient
for CMOS users. Most NTK-reading programs ignore
node sizes, anyway.
STRENGTH: number
This specifies the strengths for transistors.
This can be overridden as described for TRANS.
The default strength is 2. Most NTK-reading
programs ignore transistor strengths.
TRANS: gate-name type strength
This command declares transistor symbols. If you
need to make your own transistor gates, you will
need to use this command. The "type" is one of
N, P, or D. The strength is optional; if it is
a positive number N, then the strength of the
transistor is N; if it is missing, the strength
is the default value; if it is -N, the strength
is found in attribute number N of the transistor
gate, which must be an integer-valued attribute.
The file logntk.cnf contains TRANS commands
for all the standard LOG transistors.
PRIMITIVE: gate-name cell-name
This command declares primitive gates, gates which
should be converted into instances of cells which
have no definition. If the gate has N pins, then
the output file will call the cell with N ports,
in order of pin numbers on the gate. For example,
< primitive: a_and2 and2 >
Causes the ACTEL gate A_AND2 to convert to a call
to cell AND2. Both names may contain wildcards;
the actual commands in logntk.cnf are:
logntk: primitive a_* *
logntk: primitive a_tribuf tribuff
which maps A_AND2 to AND2, A_DFC to DFC, etc.,
and A_TRIBUF to TRIBUFF (a special case). Note
that more specific names come after more general
names. The command PRIMITIVE may be abbreviated
as PRIM.
TOP Force this to be a top-level NTK file, that is,
after the main cell has been defined, one "call"
to the cell is also written into the file. The
NETCMP program can only read top-level NTK files.
This mode is the default; you only need the TOP
command to override an earlier LEAF command.
LEAF Force this to be a leaf-level NTK file, that is,
only the cell's definition is included (plus
definitions for any subcells used). There is
usually no reason to use LEAF, since most programs
can read top-level NTK files and ignore the top part.
NOTOP Set a compatibility mode in which a LOGNTK command
on a page with no NAME command (or quoted name label)
will produce an error instead of creating a top-
level NTK file.
- Email
- john [dot] lazzaro [at] gmail [dot] com