Advanced drawing techniques
For
the more advanced schematics, TinyCAD has more advanced features.
No Connects
Normally all of the pins on
a symbol must be connected. There may be times when you wish to leave a pin
unconnected but wish to show that you haven't forgotten the pin and it is
intentionally left unconnected.
If you do not wish to
connect to a certain pin then use the no-connect option on the Toolbar. Place a
no-connect on every pin that is not to be connected to anything else.
Any unconnected pins can be
found by using the the Design Rules Checker in the Special menu.
Adding Power
Power objects in your design show
where power is connected into your circuit. Various shapes of power symbols are
defined.
You must always make the
connection to power at the end of the power object's pin. A junction may be
necessary if the connection is to the centre of a wire or where wires cross. If
a junction is necessary it will be placed automatically for you.
The shape of the power
object is ignored - it is the value of the power item which is important. All
items connected to power objects of the same value are considered connected
together.
Some component symbols,
such as the 74 TTL library symbols, are automatically connected to power. To
ensure the power is correctly connected, always use the same power names that
are used in the library. For example, when using the 74 TTL library use the
power names GND and VCC for 0v and 5v respectively.
Using Labels
A correctly
placed label
Labels enable
you to make connection between points on your design which are some way apart.
They are also useful for when many connections are required to the same point.
Labels can be
placed horizontally or vertically Notice the red
dot is placed over the wire the label is connected to.
A label should be placed above or alongside a
wire. The label is considered connected at the bottom left hand corner of the
label when the label is horizontal (Right) and the bottom right hand corner
when the label is vertical (Up). A small red rectangle shows where the label is
connected to.
All wires with the same
label name will be considered connected together. This way a connection between
the wires is formed without you having to actually draw it.
Use
labels to connect wires between sheets in the same files
A bus
connection Use wires to
connect between the bus and symbol
Adding Buses
Use labels to name
the connections to the bus.
The bus wire. Use bus labels
to name the bus
Buses can be used to
indicate a large number of connections. To help you draw a bus the repeat
options are present.
To create a bus, first draw
the bus near where you wish to connect it. Now add a bus entry to the bus.
Press 'R' (for repeat in the Edit Menu) to repeat this as necessary for the
number of entries you wish to make.
Draw a wire from the bus
entry to the connection point. Now press 'R' again, to complete all the wire
connections.
Finally you must add the
labels. Place the first label. Depending on your repeat options the label name
will be updated automatically. Place a label over each wire.
Now the bus connection is
complete!
Use the same names for the
bus entries on all connections to bus; however, the order of the names is
unimportant. Buses do not require junctions anywhere on them.
Once a
bus is in place, you may name the bus using the Bus Name tool. You may use this
to place some text next to the bus. The name can indicate how many conductors
the bus represents, by specifying just a single number, or it may qualify what
the bus is for example by calling it "Data Bus" etc.