EP4CE40 datasheet(174/488 Pages) ALTERA

174 / 488 page

8–10

Chapter 8: Configuration and Remote System Upgrades in Cyclone IV Devices

Configuration

Cyclone IV Device Handbook,

May 2013

Altera Corporation

Volume 1

1 For Cyclone IV E devices, the Quartus II software prohibits you from using the LVDS

I/O standard in I/O Bank 1 when the configuration device I/O voltage is not 2.5 V. If

you need to assign LVDS I/O standard in I/O Bank 1, navigate to

Assignments

>Device>Settings>Device and Pin Option>Configuration to change

the Configuration Device I/O voltage to 2.5 V or Auto.

AS Configuration (Serial Configuration Devices)

In the AS configuration scheme, Cyclone IV devices are configured with a serial

configuration device. These configuration devices are low-cost devices with

non-volatile memories that feature a simple four-pin interface and a small form factor.

These features make serial configuration devices the ideal low-cost configuration

solution.

f For more information about serial configuration devices, refer to the Serial

Configuration Devices (EPCS1, EPCS4, EPCS16, EPCS64, and EPCS128) Datasheet in

volume 2 of the Configuration Handbook.

Serial configuration devices provide a serial interface to access the configuration data.

During device configuration, Cyclone IV devices read the configuration data through

the serial interface, decompress the data if necessary, and configure their SRAM cells.

This scheme is referred to as the AS configuration scheme because the device controls

the configuration interface.

1 If you want to gain control of the EPCS pins, hold the nCONFIG pin low and pull the

nCE

pin high to cause the device to reset and tri-state the AS configuration pins.

Single-Device AS Configuration

The four-pin interface of serial configuration devices consists of the following pins:

■

Serial clock input (DCLK)

■

Serial data output (DATA)

■

Active-low chip select (nCS)

■

AS data input (ASDI)

EP4CE40 Datasheet(PDF) 174 Page - Altera Corporation