Intel® Quartus® Prime Pro Edition User Guide: PCB Design Tools

ID 683768
Date 8/01/2023
Public

A newer version of this document is available. Customers should click here to go to the newest version.

Document Table of Contents

2.5.12.4. Constant Definition

The constant definition block of the output simulation SPICE deck instantiates the voltage sources that controls the configuration modes of the I/O buffer.

Constant Definition Block

* Constant Definition
voeb oeb 0 0 * Set to 0 to enable buffer output
vopdrain opdrain 0 0 * Set to vc to enable open drain
vrambh rambh 0 0 * Set to vc to enable bus hold
vrpullup rpullup 0 0 * Set to vc to enable weak pullup
vpci rpci 0 0 * Set to vc to enable pci mode
vpcdp4 rpcdp4 0 rp4 * These control bits set the IO standard
vpcdp3 rpcdp3 0 rp3
vpcdp2 rpcdp2 0 rp2
vpcdp1 rpcdp1 0 rp1
vpcdp0 rpcdp0 0 rp0
vpcdn4 rpcdn4 0 rn4
vpcdn3 rpcdn3 0 rn3
vpcdn2 rpcdn2 0 rn2
vpcdn1 rpcdn1 0 rn1
vpcdn0 rpcdn0 0 rn0
vdin din 0 pulse(0 vc 0s 0.2ns 0.2ns 8.5ns 17.4ns)

Where:

  • Voltage source voeb controls the output enable of the buffer.
  • vopdrain controls the open drain mode for the I/O.
  • vrambh controls the bus hold circuitry in the I/O.
  • vrpullup controls the weak pullup.
  • vpci controls the PCI clamp.
  • The next ten voltage sources control the I/O standard of the buffer and are configured through a later library call.
  • vdin is connected to the data input of the I/O buffer.
  • The edge rate of the input stimulus is automatically set to the correct value by the Intel® Quartus® Prime software.