Article ID: 000074709 Content Type: Product Information & Documentation Last Reviewed: 09/11/2012

How do I assign VREF pins in the MAX PLUS® II or Quartus® II software for MAX® 7000B devices?

Environment

BUILT IN - ARTICLE INTRO SECOND COMPONENT
Description

For MAX 7000B, there are two fixed location voltage reference pins called VREFA and VREFB in the pin table. These pins are dual purpose and will act as regular I/O pins if not enabled in software as the voltage reference (VREF) for any input pin that is assigned a voltage reference standard such as SSTL or GTL . For a given input pin with SSTL or GTL assignment, either VREFA or VREFB can be selected as its reference voltage pin. There are no restrictions that any particular pin must use VREFA or VREFB as reference.

To assign the VREF pin in MAX PLUS II software, go to Assign --> Device menu. Choose the Device Options button to open the MAX 7000B Individual Device Options dialog box. Turn on the Enable VREFA pin and/or Enable VREFB pin option.

In Quartus II software, go to Assignments --> Settings menu. Click on Device & Pin Options in the Device page of the Settings dialog box. Under General tab, select Enable Vref A pin support and/or Enable Vref B pin support option.

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MAX® 7000B CPLD