RAM 4.5 BUX II Series Manual de usuario descargar pdf (Pagina 10)

Jianjian Song LogicWorks 4 Tutorials (5/15/03) Page 10 of 14

4 Tutorial #3: A 4-Bit Counter Device with Bus Pins

4.1 Objectives: to create a sub-circuit and device symbol with bus pins

o To build customized bus port connectors.

o To build a 4-bit counter sub-circuit with bus port connectors.

o To create a device symbol for the 4-bit counter with bus pins.

o To draw a counter circuit with the created device symbol for verification.

4.2 Create bus port connectors

Open a new file for creating a device symbol. In

Device Symbol Editor, Choose “Set to primitive

type” in Options-> subcircuit/part

type and then choose Port Connector. The symbol

will then be of Type Port Connector.

Create a number of pins for a bus by choosing

Option->Add pins with, for example,

INPUT[A0..A3] for a four-bit input bus that has

signals A0 to A3.

The signal names must match those that the bus is

to be connected to. Therefore each bus port

connector can only be used once to connect signals

with same names.

A bus internal pin can be either output or input or bi-directional.

Set pins on a bus to be output pins if the pins are to be connected to inputs of a sub-circuit.

Draw a bus symbol that can be any

shape you want. Select a bus pin from

the symbol palette and place it on the

bus symbol. There are four bus pins,

one for each side of the bus symbol.

A screen capture on the right shows

how a 4-bit input bus port can be

created. Notice that the pin functions

are designated as Output, although the

bus port is an input bus port.

Make sure the pin directions and the

number of pins match the intended

application.

Save the port connector symbol to your

own library. The following are two

sample port connector symbols.

4-bit Bus Port In

bus port out

1 2 ... 5 6 7 8 9 10 11 12 13 14

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RAM 4.5 BUX II Series Manual de usuario Pagina 10