Altera OCT User Manual

2013.11.29

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Altera OCT Megafunction User Guide

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Altera On-Chip Termination (Altera OCT) allows you to dynamically calibrate I/O with reference to an
external resistor. The Altera OCT megafunction improves signal integrity, reduces board space and is
necessary for communicating with external devices such as memory interfaces.

The Altera OCT megafunction is available for Arria®10 devices only. For Arria V, Cyclone®V, and Stratix
V devices, follow the steps in Migrating Your ALTOCT Megafunction on page 1 to migrate your
megafunction.

Related Information

• Introduction to Megafunction IP Cores

• Dynamic Calibrated On-Chip Termination (ALTOCT) Megafunction User Guide

IP Migration Flow for Arria V, Cyclone V, and Stratix V Devices

The IP migration flow allows you to migrate the ALTOCT megafunction of Arria V, Cyclone V, and Stratix
V devices to the Altera OCT megafunction of Arria 10 devices.

The IP migration flow configures the Altera OCT megafunction to match the settings of the ALTOCT
megafunction, allowing you to regenerate the megafunction.

®

Note:

This megafunction only support the IP migration flow in single OCT calibration mode. If you are
using double or POD calibration mode, you do not need to migrate the megafunction.

Migrating Your ALTOCT Megafunction

To migrate your ALTOCT megafunction, follow these steps:

1. Open your ALTOCT megafunction in the MegaWizard Plug-In Manager.

2. In the Currently selected device family, select Arria 10.

3. Click Finish to open the Altera OCT megafunction in the MegaWizard Plug-In Manager. The MegaWizard

Plug-In Manager configures the Altera OCT megafunction settings similar to the ALTOCT megafunction
settings.

4. If there are any incompatible settings between the two, select new supported settings.

5. Click Finish to regenerate the megafunction.

6. Replace your ALTOCT megafunction instantiation in RTL with the Altera OCT megafunction.

Note:

©

2013 Altera Corporation. All rights reserved. ALTERA, ARRIA, CYCLONE, HARDCOPY, MAX, MEGACORE, NIOS, QUARTUS and STRATIX
words and logos are trademarks of Altera Corporation and registered in the U.S. Patent and Trademark Office and in other countries. All other words
and logos identified as trademarks or service marks are the property of their respective holders as described at www.altera.com/common/legal.html.
Altera warrants performance of its semiconductor products to current specifications in accordance with Altera's standard warranty, but reserves the
right to make changes to any products and services at any time without notice. Altera assumes no responsibility or liability arising out of the application
or use of any information, product, or service described herein except as expressly agreed to in writing by Altera. Altera customers are advised to
obtain the latest version of device specifications before relying on any published information and before placing orders for products or services.

The Altera OCT megafunction port names may not match the ALTOCT megafunction port names,
so simply changing the megafunction name in the instantiation is not sufficient.

ISO
9001:2008
Registered

2

Parameter Settings

Parameter Settings

This section describes the Altera OCT megafunction parameter settings. You can parameterize the
megafunction using the MegaWizard Plug-In Manager.

Table 1: Altera OCT MegaWizard Plug-In Manager Page Options and Description

Plug-in Man-

ager Page

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DescriptionConfiguration SettingMegaWizard

2a

Which action do you want to perform?1

Which device family will you be using?

Which type of output file do you want to create?

Return to this page for another create operation

Calibration mode3

Select from the following options:

• Create a new custom megafunction
variation

• Edit an existing custom megafunction
variation

• Copy an existing custom megafunction
variation

Select Altera OCT from the I/O category.Select a megafunction from the list below

Specify the device family that you want to
use.

Choose Verilog HDL (.v) as the output file
type.

Specify the name of the output file.What name do you want for the output file?

Turn on this option if you want to return
to this page to create multiple
megafunctions.

Defines the OCT calibration mode. Select
from the following options:

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• Single: For a given voltage, the OCT
block can generate calibration code only
for a single pair of series/parallel
termination values.

• Double: For a given voltage, the OCT
block can generate calibration code for
up to two pairs of series/parallel
termination values.

• POD: Configures the OCT block to
generate calibration code specific for
pseudo-open drain (POD) I/O
standards.

Altera OCT Megafunction User Guide

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OCT Block OCT Logic

rzqin

Altera OCT

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Features

The following figure shows the top-level diagram of the Altera OCT megafunction.

Figure 1: Altera OCT Megafunction Top-Level Diagram

The Altera OCT megafunction provides the following features:

Features

3

• RZQ pin—Dual-purpose pin. When used with OCT, the pin connects to an external reference resistor
to calculate the calibration codes to implement the required impedance.

• OCT block—Generates and sends calibration code words to the I/O buffer blocks.

• OCT logic—Receives the calibration code words serially from the OCT block and sends the calibration

code words in parallel to the buffers.

RZQ Pin

Each OCT block has one RZQ pin. RZQ pins are dual-purpose, which means that if the pins are not connected
to the OCT block, you can use the pins as regular I/O pins. Calibrated pins must have the same VCCIO as
the OCT block and the RZQ pin. Calibrated pins connected to the same OCT block must have the same
series and parallel termination values. You can apply location constraints on the RZQ pins to determine the
placement of the OCT block because the RZQ pin can only be connected to its corresponding OCT block.

OCT Block

The OCT block is a component that generates calibration codes to terminate the I/Os. When calibrating,
the OCT matches the impedance seen on the external resistor through the rzqin port. Then, the OCT
block generates two 16-bit calibration code words; one word calibrates the series termination while the other
calibrates the parallel termination. A dedicated bus serially sends the words to the OCT logic.

OCT Logic

The following figure shows the internals of an OCT logic.

Altera OCT Megafunction User Guide

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