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Guiding Principles for Annotation of Multi-Section Parts in OrCAD Capture





Annotating Heterogenous Parts in a Design

Annotating Homogeneous Parts in a Design

Annotating Special Cases of Heterogeneous Parts in a Design


Annotating Heterogeneous Parts in a Design

A Heterogeneous package consists of the logical parts that are different from each other in terms of graphics, numbers of pins, or properties.

For heterogeneous parts, following are the three main guiding principles for annotation:

Unconditional Annotation with Preserve User Assigned Reference

When you annotate a design with the Preserve User Assigned Valid References option selected in Unconditional Annotation, Capture does the following:

It finds the best fit parts with different designators in the design and assigns them the same reference numbers.

If best fit parts with the same designator are not found in the design and there is no conflict, a new reference number is assigned to the unreferenced part in the design. In this case, the new reference number is the lowest unused number in the design.

If a conflict occurs, annotation fails.

Figure 1-1  Unconditional Annotation with Preserve User Assigned Reference

In Figure 1-1, note that the parts fulfilling the best fit criteria and with different designators are assigned the same reference number after annotation. The parts with no best

fit and no conflict are assigned the lowest unused number, that is, one, as the new reference number after annotation. The new reference number increments when a new package of the parts is formed.

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Unconditional Annotation without Preserve User Assigned Reference

When a design is annotated with the Preserve User Assigned Valid References option deselected in Unconditional Annotation, Capture assigns new reference numbers to all the parts in the design. The new reference number starts from one and increments when one package is complete.

In case of conflict, Capture stops annotating the design and does not assign any further reference numbers.

Figure 1-2 Unconditional Annotation without Preserve User Assigned Reference

In Figure 1-2, note that Capture assigned new reference numbers to all the parts, irrespective of the user-assigned references. Capture ignored user-assigned references as the Preserve User Assigned Valid References option was deselected in the Annotate window. The new reference number, which starts from one, increments when the package is complete

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Incremental Annotation

When a design is annotated in the Incremental Reference Update mode,

  the parts that fulfill the best fit criteria and that have different designators are assigned the same reference number, and

  the unreferenced parts are assigned new reference numbers.

In this case, the new reference number is the largest-used reference number in the design plus one. It is incremented when the package is complete.

Figure 1-3 Incremental Annotation with Preserve User Assigned Reference

In Figure -3 , the parts with best fit and with different designators are assigned the same reference number and the new reference number is assigned to the unreferenced parts. The new reference number is equal to the largest-used reference number in the design plus one. It is incremented when the package is complete.

In this case, 20 is the largest-used reference number in the design; therefore, the new reference number assigned is 21. When one package is completed, the part in the next package will have 22 as the new reference number.

Annotating Homogeneous Parts in a Design

A Homogeneous package contains logical parts that are identical except for the pin names and numbers.

For homogeneous parts, following are the three guiding principles for annotation:

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Unconditional Annotation without Preserve User Assigned References

When a design is annotated with the Preserve User Assigned Valid References option deselected in the Unconditional Annotation mode, Capture starts assigning a new reference number to all the parts. The new reference number always starts from one and increments when a new package is formed in the design.

When the Preserve User Assigned Valid References option is deselected, the user-assigned referenced parts will again be referenced along with the unreferenced parts in a design.

Figure 1-4  Homogeneous Parts: Unconditional Annotation without Preserve User Assigned References

In Figure 1-4, Capture has assigned a new reference number, which starts from one, to all the parts. Capture ignored some of the part’s user-assigned references as the Preserve User Assigned Valid References option was deselected.

When a new package is formed, Capture increments the reference number and assigns the incremented reference number to the part in the new package.

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Unconditional Annotation with Preserve User Assigned References

When a design is annotated with the Preserve User Assigned Valid References option selected in the Unconditional Annotation mode, Capture preserves the user-assigned references. It assigns new reference numbers to the unreferenced and non user-assigned parts in a design.

The new reference number always starts from one and is incremented when a new package
is formed in a design.

Figure 1-5  Homogeneous Parts: Unconditional Annotation with Preserve User Assigned References

In Figure 1-5, Capture preserves the user-assigned references in the design during annotation. However, unreferenced and non user-assigned parts are assigned a new reference number, which starts from one. When a package is complete with all the parts, Capture increments the reference number and assigns the incremented reference number to the parts in the new package.

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Incremental Annotation

When a design is annotated in the Incremental Reference Update mode, Capture first finds the best fit parts. If two or more parts are considered as best fit parts, the same reference number is assigned to them.

In case no best fit is found in the design, Capture assigns a new reference number to the rest of the parts in the design. The new reference number is the largest-used reference number in a design plus one, and is incremented when the new package is formed in a design.

Figure 1-6  Homogeneous Parts: Incremental Annotation

In Figure 1-6, Capture assigned the same reference number to all the parts in the design that fulfilled the best fit criteria. A new reference number, which is equal to the largest- used reference number plus one, is assigned to parts that do not fulfill the best fit criteria.

The new reference number is incremented when one package is complete, and, the incremented reference number is assigned to the part in the new package.

In this example, the largest-used reference number is . Therefore, the new reference number assigned is .

Annotating Special Cases of Heterogeneous Parts in a Design

For heterogeneous parts, conflict can occur during annotation when no best fit is found in the design and when two parts have the same designator. Select the First Match option in the Cadence TCL/TK utilities menu to resolve conflict during annotation.

Following are three cases that illustrate conflicts for heterogeneous parts, and how these conflicts are resolved using the First Match option:

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Unconditional Annotation with Preserve User Assigned Reference

When a design is annotated with the Preserve User Assigned Valid References option selected in Unconditional Annotation, Capture first finds the best fit parts in the design.

In case of any conflict, the First Match option is used to resolve the conflict. If the First Match option is selected, Capture finds the first matched part in the design to form one complete package. Capture adds the other part, which has the same designator, in the next package.

In this case, the assignment of a new reference number will start from the lowest-unused reference number in the design. The new reference number is incremented when one package is complete.

Before Annotation

When you annotate a design which has parts that do not fulfill the best fit criteria and parts that fulfill the best fit criteria, Capture will annotate only those parts that fulfill the best fit criteria or those parts that do not result in a conflict.

Figure 1-7  Special Case: Before Annotation

In Figure -7, note that there are two instances of the U?B part, that is, two parts with the same designator. When Capture finds two parts with the same designator in a design during annotation, it fails to annotate the parts and generates an annotation failure error message.

Therefore, if the design is annotated without selecting the First Match option, Capture will annotate the parts in the first row only and will not annotate the parts further.

Annotation without First Match option

Note that in Figure 1-8, Capture annotated only those parts that meet the best fit criteria, that is, the parts in the first row. For the rest of the parts, a conflict occurred and annotation failed as Capture cannot package two parts, with the same designator, together in one package.

Capture generates the following error in the session log for annotation failure:

ERROR(ORCAP-): Cannot perform annotation of heterogeneous part 'U?A(Value -ECL) at location (X.xx, Y.yy) on page PAGEX', part has not been uniquely grouped (using a common User Property with differing Values) or the device designation has not been chosen.

Figure 1-8 Special Case: After Annotation without First Match option

Annotate the design again with the First Match option selected to resolve this error.

Annotation with First Match option

To annotate a design with the First Match option selected, do the following:

. Select the design file in Project Manager and choose Accessories – Cadence TCL/TK

– Utilities

The TCL/Tk Dashboard window appears.

2. Choose Extended Preferences option from the Application Utilities area of the TCL/Tk Dashboard window and click Launch.

The Extended Preferences Setup window appears.

. Choose Design Annotation from the Groups area of the Extended Preferences Setup window.

4. Choose First Match option from the Settings area of the Extended Preferences Setup window.

5. Click Apply to save the settings or Click OK to save the settings and close the Extended Preferences Setup window.

6. Click Done to close the TCL/Tk Dashboard window.

If the First Match option is selected, Capture annotates the design by finding the first matched part in the design and by adding that part in one package. Capture includes the other instance of the part, which has the same designator, in the next package and increments the part’s reference number by one.

Figure 1-9  Special Case: After Annotation with First Match option selected

In Figure 1-9, note that Capture has annotated the design without any errors. Therefore, whenever you want to perform unconditional annotation with the Preserve User Assigned Valid References option selected, always choose the First Match option.

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Unconditional Annotation without Preserve User Assigned Reference

When a design is annotated with the Preserve User Assigned Valid References option deselected in Unconditional Annotation, Capture first finds the best fit in the design.

In case of any conflict, the First Match option is used to resolve the conflict. If the First Match option is selected, Capture finds the first matched part in the design to form one complete package. Captures adds the other part, with the same designator as the first one, in the next package with an incremented reference number.

When the conflict is resolved, the new reference numbers are assigned to all the parts in a design. These reference numbers start from one and are incremented when a package is complete.

Before Annotation

When you annotate a design which has parts that do not fulfill the best fit criteria and parts that fulfill the best fit criteria, Capture will annotate only those parts that meet the best fit criteria or those parts that do not result in a conflict.

Figure 1-0 Special Case: Before Annotation

In Figure 1-0, note that there are two instances of the U?B part, that is, two parts with the same designator. During annotation, when Capture finds that there are two parts with the same designator in the design, it fails to annotate the parts and generates an annotation failure error message.

Therefore, in this case, if we annotate the design without the First Match option, Capture will annotate the parts in the first row only, not the parts in the second row.

Annotation without First Match option

Note that in Figure 1-1, Capture annotated only the first row of the design as those parts fulfilled the best fit criteria. For the rest of the parts, a conflict occurred and annotation failed as Capture cannot package the two parts, with the same designator, together in one package.

Capture generates the following error in the session log for annotation failure:

ERROR(ORCAP-1376): Cannot perform annotation of heterogeneous part 'U?B(Value 1010-ECL) at location (X.xx, Y.yy) on page PAGEX', part has not been uniquely grouped (using a common User Property with differing Values) or the device designation has not been chosen.

Figure 1-1 Special Case: After Annotation without First Match option

To resolve this error, annotate the design again with the First Match option selected.

Note: In this case, the design is annotated with the Preserve User Assigned Valid References option deselected. Therefore, the assignment of the new reference number starts from the first part. The new reference number is equal to the lowest-unused reference number in the design.

Annotation with First Match option

To annotate the design with the First Match option selected, follow the steps mentioned in the Annotation with First Match option section.

When the First Match option is selected, Capture annotates the design by finding the first matched part in the design and adds that part in one package. Capture includes the other instance of the part, which has the same designator, in the next package and increments the part’s reference number by one.

Figure 1-2 Special Case: After Annotation with First Match option

In Figure 1-2, note that Capture has annotated the design without any error. As unconditional annotation is performed with the Preserve User Assigned Valid References option deselected, the user-assigned referenced parts are also reassigned. Therefore, for error-free unconditional annotation with the Preserve User Assigned Valid References option deselected, choose the First Match option.

Incremental Annotation

When a design is annotated in the Incremental Reference Update mode, Capture follows the best fit mechanism. If two or more parts, with different designators, meet the best fit criteria, the same reference number is assigned to those parts. In this case, Capture ignores the user- assigned references of the part as the Preserve User Assigned References option does not play any role in incremental annotation.

In case no parts meet the best fit criteria, Capture assigns new reference number to the unreferenced and non user-assigned parts in a design. The new reference number is equal to the largest-used reference number in a design plus one. It is incremented when a new package is formed in a design.

In case of any conflict, the First Match option is used to resolve the conflict. When the First Match option is selected, Capture finds the first matched part in the design to form one complete package. Captures adds the other part, which has the same designator, in the next package and increments the part’s new reference number by one. For example, if the largest-used reference number is 20, Capture will assign 21 as the new reference number to the unreferenced parts in the first package of the design. In the next package, part will have 22 as the new reference number.

Before Annotation

In Figure 1-3, note that there are two instances of the U?B part in the design, that is, two parts with the same designator. When Capture finds that there are two parts with the same designator in a design during annotation, it fails to annotate the parts and generates an annotation failure error message.

Figure 1-3 Special Case: Before Annotation

Therefore, when the design is annotated without the First Match option, Capture will annotate the parts in the first row only and will not annotate further.

Annotation without First Match option

In Figure 1-4, Capture annotated only those parts—the parts in the first row— that met the best fit criteria. For the rest of the parts, annotation failed as Capture cannot package two parts, with the same designator, together in one package.

Capture generates the following error in the session log for annotation failure:

ERROR(ORCAP-1376): Cannot perform annotation of heterogeneous part 'U?B(Value 1010-ECL) at location (X.xx, Y.yy) on page PAGEX', part has not been uniquely grouped (using a common User Property with differing Values) or the device designation has not been chosen.

Figure 1-4 Special Case: After Annotation without First Match option

To resolve the annotation failure error, annotate the design again with the First Match option selected.

Annotation with First Match option

To annotate the design with the First Match option selected, follow the steps mentioned in the Annotation with First Match option section.

When the First Match option is selected, Capture annotates the complete design by finding the first matched part in the design and adds that part to one package. Capture includes the other instance of the part, with the same designator, in the next package and increments the part’s new reference number by one.

In Figure 1-5, Capture annotated the design completely without any error. The new reference number (the largest-used reference number in the design before annotation plus one), which is assigned to the part, is six.

Figure 1-5 Special Case: After Annotation with First Match option

Therefore, whenever you want error-free incremental annotation, choose the First Match option in Capture.