Symbols Generator

The Symbols Generator is a full-featured tool provided to assist you in creating and updating both functional block symbols and related PCB symbols.

The default binding type for ports created by the Symbols Generator is Pin.

Creating a New Symbol Using the Symbols Generator

1. Invoke the Symbols Generator by doing one of the following:

• From the main menu in PADS I/O Designer, select Symbol > Symbols Generator.

• Click the icon on the toolbar or at the top of the Symbol Window.

2. On the Basic Settings page, enter information for:

• Symbol name

The naming convention for PCB symbols is <Symbol name>_pcb. Do not use names with characters following _pcb, as this may cause problems when creating functional symbols split by PCB afterwards. Functional symbols should always be named differently to PCB symbols (for example, without the _pcb) to avoid overwriting them.

• Use signals: During symbol generation, whether to use All signals or Selected only.

• Pin Limits for All Symbol Types:

• Always split symbols larger than page size: This option applies to functional and PCB symbols.

Buses are not split between symbols even if the resulting symbol is larger than the page size.

• Always split symbols with more pins than <number>: This option applies to functional and PCB symbols.

3. Click Next to display the Symbol Settings page.

Note
	The information in the right hand column of the Symbol Settings page is specific to the selected (highlighted) pin type in the central column. Any changes you make in the right hand column apply to the selected pin type only. When you select a different pin type, the information in the right hand column changes to reflect any differences in the information for that pin type.

4. On the Symbol Settings page, enter information for:

• Pins usage:

• Create separate symbols for these pins

• Add these pins to I/O symbols

• Design type: Specifies whether or not the design type is hierarchical or flat:

• Hierarchical: Enables all controls below

• Flat: Reduces the symbol type to PCB and selects it

• Symbols type: Functional, PCB or Both.

5. To specify advanced symbol settings, click More >> to display the Fracturing, Labels, and Appearance tabs. The options available under these tabs depends on the selected pin group - see Figure 9-1. These advanced settings are described in the following.

Fracturing tab
Select whether the symbol should be split. The options available here depend on whether you have chosen to create Functional Symbol, PCB Symbol, or both. Following is a list of symbol fracturing options with explanations (Figure 9-1 shows how the list changes depending on the selected pin group).

• Split PCB and Functional Symbols:

• Do not split: Create a single functional/PCB symbol depending on the Symbol Type selected.

• Split only PCB symbols: This option enables you to specify a more detailed split method for PCB symbols.

• Split functional and PCB symbols: This option enables you to specify more detailed split method for both functional and PCB symbols. It is only available if both symbols are created (Design Type = Hierarchical).

• Fracturing Scheme for PCB and Functional Symbols:

• Split by power banks: Create separate symbols for groups of pins that belong to different power banks.

• Separate data and control signals: Create separate symbols for buses and scalar signals.

• Separate signals connected to different components: Create separate symbol for groups of signals that belong to different HDL units.

• Split by signal: Only available for PCB power pins.

• Split by channel and Split by block: Only available for MGT pins.

• Split by PCB symbols: Create functional symbols split by existing PCB symbols (that is, imported from the central library).

• Split by functional symbols: Create functional symbols split by existing functional symbols (that is, imported from the central library).

Labels tab
Label settings are available for all types of pins. Once defined, these settings do not normally need to be changed (as is in the case of symbol generation).

• Functional block: Sets port labels for the functional block. The default port label depends on the pin type.

• PCB symbol: Sets port labels for the PCB symbol. The default port label depends on the pin type.

Appearance tab
These settings are available for all types of pins. Once defined, these settings do not normally need to be changed (as is in the case of symbol generation).

• Symbols: Specifies the following:

• Symbol name

• Symbol description

• Functional symbol background

• PCB symbol background

• Ports: Sets the port position for the pin. It is used even if pins of the current type are added to other symbols. For example, select Left to insert the port to the left of the symbol. This option relates to the Clk pin position or the VCC/GND pins position only.
  Selecting the Left and Right option can assist in schematic updating and maintenance by allowing the symbol to grow vertically, leading to fewer connection issues.

6. Click Next > to display the Summary page.

7. On the Summary page, review the changes you have made. The page summarizes symbols and ports that will be created, deleted, or changed after clicking Finish. Click More >> to view advanced summary information.

8. Click Finish.

The symbols are created and appear in the Symbol Window. You can click Finish at anytime to create a symbol using the current settings.

To display the Divide Ports page, check Adjust symbols manually on the Summary page and click Next. Use this page to add unplaced signals and pins to symbols (existing or created by the Symbols Generator). The page provides an easy way to handle signals and pins that have not been assigned and therefore are not part of any symbol.

Several pages contain the buttons Load Defaults (loads the default settings) and Save as Defaults (saves the current settings as defaults).

Figure 9-1 shows the different option available depending on the selected pin group.

Figure 9-1. Symbol Settings Page (Advanced Options)

Updating Symbols Using the Symbols Generator

Once symbols have been created, the Symbols Generator can be used to update them. In this case, it is not necessary to re-enter the information for symbol fracturing, appearance or port labels; PADS I/O Designer uses the settings entered when creating the symbol.

1. Invoke the Symbols Generator by doing one of the following:

• From the main menu in PADS I/O Designer, select Symbol > Symbols Generator.

• Click the button at the top of the Symbol Window.

2. The Symbols Generator opens on the Basic Settings page. Select Update symbols under Symbols and click Next and Finish.

Limitations

It is not possible to update symbols using the Symbols Generator when:

• No symbol exists

• All existing symbols have the Automatic Symbol Update flag set to Prevent.

• All existing symbols were created manually

• All existing symbols were created semi-automatically (with multiple steps in Symbols Generator) for Selected pins only or when functional and PCB symbols were not created in a single event.

Updating Symbols in Databases Created Using Older Versions of PADS I/O Designer

The Symbols Generator does not provide update functionality for all symbols created in older versions of PADS I/O Designer (pre-9.1 versions). (The reason for this is that symbols from older versions have a prevent flag set after loading.) In order to use the update symbols function, symbols must be created using the Symbols Generator.

To support updating symbols from PADS I/O Designer versions prior to 9.1, the tcl command symbolwizard is supported in PADS I/O Designer 9.2.