Configuration Handbook - Kamami.pl

Configuring Stratix II & Stratix II GX Devicespin after a reset time-out period (maximum of 100 µs). When nSTATUSreturns to a logic high level, the configuration device tries to reconfigurethe device.When CONF_DONE is sensed low after configuration, the configurationdevice recognizes that the target device has not configured successfully.Therefore, your system should not pull CONF_DONE low to delayinitialization. Instead, use the CLKUSR option to synchronize theinitialization of multiple devices that are not in the same configurationchain. Devices in the same configuration chain will initialize together iftheir CONF_DONE pins are tied together.1 If you are using the optional CLKUSR pin and nCONFIG is pulledlow to restart configuration during device initialization, youneed to ensure that CLKUSR continues toggling during the timenSTATUS is low (maximum of 100 µs).When the device is in user-mode, pulling the nCONFIG pin low initiatesa reconfiguration. The nCONFIG pin should be low for at least 2 µs. WhennCONFIG is pulled low, the device also pulls nSTATUS and CONF_DONElow and all I/O pins are tri-stated. Because CONF_DONE is pulled low, thisactivates the configuration device because it sees its nCS pin drive low.Once nCONFIG returns to a logic high level and nSTATUS is released bythe device, reconfiguration begins.Figure 7–22 shows how to configure multiple devices with an enhancedconfiguration device. This circuit is similar to the configuration devicecircuit for a single device, except Stratix II or Stratix II GX devices arecascaded for multi-device configuration.Altera Corporation 7–59May 2007 Stratix II Device Handbook, Volume 2