A3P250-VQ100 其他数据使用手册 - Microchip（微芯）

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Subject

Addendum to PCN1309 and PCN1309A – Synopsys Synplify Pro Software Bug Regarding Safe State Machine Recovery

Description

Microsemi and Synopsys have recently become aware of a scenario that can result in a state machine design not being

implemented with logic circuits which force the state machine into a reset state if an illegal state is detected.

Description of the Problem

When a design is synthesized with the one-hot state machine encoding style and includes state machines with only two

states, Synplify Pro may not recognize them as state machines. If the state machine is marked for “safe” implementation,

and this bug affects the design, then the inferred extra logic that forces a reset during an illegal state condition will not be

added. This problem can occur only when of the following conditions are true.all

as in , does not result in this bug (if the Implementation Options encoding is set to “default”).syn_encoding=”safe,onehot”

Method of Identifying an Affected Design

You can verify whether this issue really affected your design by checking if all the following conditions are true for the

Synplify project, where the design was synthesized:

The design has “onehot” selected as the .Default Enum Encoding

The state machine is marked to be implemented with the “safe” attribute.

The state machine has only two possible states.

The state machine does not have a attribute.syn_state_machine=”true”

The .srr report does not have an ‘Encoding state machine X’ message.

The safe state machine logic does not exist.

Change the to be “default” within the Implementation Options.Default Enum Encoding

Add the attribute to the state machine signal.syn_state_machine=”true”