FAQ

ABEL: How to create a schematic symbol for a bus?

The ABEL language does not have a direct way to define a bus for pins. The bus is often defined as such with an internally defined bus. 

Here is an example:

Problem:

Although the schematic tool allows the user to generate a bus on the symbol from any ABEL module, users often get errors similar to the following:

"Logical Error 13534: Signal 'Q_0_' of Submodule 'count512' can't be used in the interface. Only pin is allowed."

This indicates that lower-level signal names do not match with the top-level names. The top-level schematic signal name Q[0:8] is translated into Q_0, Q_1, etc. They do not match with the Abel pin names Q0, Q1, etc.

Solution:

Users can edit the symbol to link the bus name Q[0:8] to the actual pin names Q0...Q8. Following the steps listed below allows the user to remove the error.

1. Open a top-level schematic file that contains the symbol with the bus (count512)


2. Click Edit=>symbol


3. Click the symbol (count512) in the schematic editor - The Symbol Editor is opened and count512 is shown


4. Click Edit=>Attribute=>Pin Name Location - A Dialogue Box "Pin Name" is opened, and "Don't Show" is checked


5. Click the pin port Q[0:8] - The Q[0:8] is disable now


6. Click Add=>Text, then input "Q[0:8]" and put to the symbol


7. Click Edit=>Attribute=>Pin Attribute


8. In Pin Attribute Dialogue, click Q[0:8], and change it with Q0,Q1,Q2,Q3,Q4,Q5,Q6,Q7,Q8


9. Save the Symbol Editor and close it


10. Save schematic