CDL(10.6) CDL(10.6)
NAME
cdl - circuit description language
DESCRIPTION
The circuit descriptions used by the various circuit design
aid programs are expressed in dialects of CDL - the circuit
design language described below. This is half of a complete
project specification; namely an electrical circuit with
chips, pins and connecting signals. The other half, a
physical layout with pins and chip positions, is described
in fizz(10.6) format. The commands described below are rec-
ommended; others exist and may work but are regarded as
obsolete.
Logic design
A circuit consists of chips connected by signals. The point
of connection is denoted by a pin. Each chip has a type
which describes its logical and electrical characteristics.
(For example, 74S181 is a chip type.)
Types, signals, and chips are identified by name. Pins are
identified by name and number. A name is a string of let-
ters, digits, or any of the characters +-.$/:<=>[]_. Some-
times, the first character may not be a digit. A name may
not be longer than 16 characters.
In the following description, literals appear as
constantwidth and names are in italic. [ ] enclose an
optional item and a list of items is written
{item}
Commands are separated by either newline or semi-colon. A
comment starts with a % and ends with a newline and may
appear on any line. All white space serves only to separate
tokens.
General
.f [ file ]
Subsequent input originated in file . If file is not pre-
sent, the previous file name is restored.
.q
End of file.
Signal Description
signal [ pin-number ] [ [ , ] pin-name ]
name = signal
Lines that do not start with a period are signal definition
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CDL(10.6) CDL(10.6)
lines. Signal definitions refer to the most recent .c com-
mand. The pin name and number refer to the chip.
Circuit Description
.c name [ [ , ] type ]
Instantiates the chip name with type type. This is typically
used for I/O connectors. The command may occur more than
once. The type of a chip need only be specified once in a
circuit description. Signal descriptions that follow a .c
command refer to pins on the chip.
.c name = chip
Establish name as a synonym for the previously defined chip.
.m name1 name2
Macro parameter definition. The signal name1 is to be asso-
ciated with macro parameter name2.
Chip Type Description
.t name package [pin] ...
Define a chip type name. The name of the package in which it
is installed, and pin numbers, pin, for the special signal
connections are specified. The special voltage pin numbers,
if present, must be in the same sequence with which the spe-
cial signals are numbered. This usage is discouraged; use
the .t[tT] commands described below. (See .v command.) All
commands of the form .t? are meant to follow a .t line.
.t name = type
name is a synonym for type .
.tt sequence_of_single_character_pin_descriptors
The number of characters must equal the numbers of pins on
this type. The meaning of the descriptors is given in
smoke(10.1).
.tT sequence_of_single_character_pin_descriptors
This means the same as the equivalent .tt command except
that every [gvwxyz] pin must have a corresponding .vb pin.
.tp name number ...
The given pin name is associated with the pin number. Name
may contain generators such as Q[0-7] which cause pin names
Q0 ... Q7 to be assigned to the pin numbers given. Multiple
bracket constructs may be used. In any case, the resulting
list is lexicographically sorted before assigning to pin
numbers.
SEE ALSO
cdm (10.1)
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