Altera® Quartus® Prime Standard Edition Settings File Reference Manual

ID 683084
Date 5/08/2017
Public
Document Table of Contents

1.10.235. OUTPUT_ENABLE_GROUP

Assigns an output enable group number for the specified node. Turning on this option directs the Fitter to view the specified nodes as an output enable group so as not to violate the requirements for the maximum number of pins driving out of a VREF group when a voltage-referenced input pin or bidirectional pin is present. For bidirectional pins, the Fitter determines all possible pins that may potentially drive out when any bidirectional pin is driving in by looking at the output enable of all the bidirectional pins in the VREF group. This behavior can result in the VREF group exceeding the maximum number of outputs and result in a no fit. Turning on the 'Output Enable Group' option allows you to specify an output enable group for specific pins, thus allowing you to specify which pins in the design are driving in and out at the same time. The Fitter only considers pins as potential outputs when they are in separate output enable groups or when they are not in an output enable group; by specifying an output enable group, you can lower the total number of outputs in the VREF group when any pin is driving in. As a result, the Fitter does not count all of the potential outputs of the bidirectional pins and the number of outputs in the VREF group remains in the legal range. You should turn on this option when the Fitter cannot detect the output enable group of the pins in the VREF group, for example when the output enables come from a state machine or complex logic. For detailed information on the number of outputs supported by a VREF group, refer to the data sheet for the device family, which is available from the Literature section of the Altera web site.

Type

Integer

Device Support

  • Arria GX
  • Arria II GX
  • Arria II GZ
  • Arria V
  • Arria V GZ
  • Cyclone
  • Cyclone 10 LP
  • Cyclone II
  • Cyclone III
  • Cyclone III LS
  • Cyclone IV E
  • Cyclone IV GX
  • Cyclone V
  • HardCopy II
  • HardCopy III
  • HardCopy IV
  • MAX 10
  • MAX II
  • MAX V
  • Stratix
  • Stratix GX
  • Stratix II
  • Stratix II GX
  • Stratix III
  • Stratix IV
  • Stratix V

Notes

This assignment supports wildcards.

This assignment supports Fitter wildcards.

Syntax


		set_instance_assignment -name OUTPUT_ENABLE_GROUP -to <to> -entity <entity name> <value>
	

Example


		set_instance_assignment -name OUTPUT_ENABLE_GROUP 2 -to output_pin[0]
set_instance_assignment -name OUTPUT_ENABLE_GROUP 2 -to output_pin[1]