Altera Stratix GX Guide de l'utilisateur télécharger pdf (Page 227)

Altera Corporation 9–1

January 2005

9. Reset Control &

Power Down

Introduction

Stratix

GX transceivers offer multiple reset signals to control separate

ports of the transceiver channels and transceiver blocks, as shown in

Figure 9–1. The Quartus

II software sets each unused channel to a

power-down mode to reduce power consumption.

Figure 9–1. Reset Control Diagram

Power On Reset

(POR)

At power on, the Stratix GX transceiver uses built-in circuits that handle

the reset of the digital and analog circuits. After power on reset (POR), the

Stratix GX block is guaranteed to be in a known state.

USER Reset &

Enable Signals

Each transceiver block and channel in the Stratix GX transceiver block has

individual reset signals to reset the digital and analog portions of the

channel. The txdigitalreset, rxdigitalreset, and

rxanalogreset signals affect the channels individually. The

pll_areset and pllenable signals affect the entire transceiver block.

The pll_areset signal is a power-down signal and powers down the

entire transceiver block. The analog circuitry is powered down when the

pll_areset signal goes high. Although there is no specific requirement

on the duration of the pll_areset signal, Altera

lab experiments have

shown that 1 ms is a safe value. If you use the pll_areset signal to

power down the analog circuitry, Altera recommends that you use the

pll_locked and rx_freqlocked signals from the transceiver block to

implement your reset logic.

Reset

Control

txdigitalreset

rxdigitalreset

rxanalogreset

pll_areset

pllenable

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Altera Stratix GX Guide de l'utilisateur Page 227