Configuration Handbook - Kamami.pl

Device Configuration OptionsYou can set device options in the MAX+PLUS ® II development softwareby choosing Global Project Device Options (Assign menu). Table 6–1summarizes each of these options.Table 6–1. Configuration Options (Part 1 of 5)Device OptionAuto-restartconfiguration aftererrorRelease clearsbefore tri-statesOption UsageWhen a configuration erroroccurs, the FPGA drivesnSTATUS low, which resetsitself internally. The FPGAwill release its nSTATUS pinafter a reset time-out period.The nSTATUS pin is thenpulled to V CC by a pull-upresistor, indicating thatreconfiguration can begin.You can choose whetherreconfiguration is startedautomatically or manually (bytoggling the nCONFIG pin).During configuration, thedevice I/O pins are tri-stated.During initialization, you canchoose the order forreleasing the tri-states andclearing the registers.Default Configuration(Option Off)Reconfiguration startsautomatically and the systemdoes not need to pulsenCONFIG. After the FPGAreleases nSTATUS and it ispulled to V CC by a pull-upresistor, reconfiguration canbegin.In passive configurationschemes that use aconfiguration device, theFPGA’s nSTATUS pin is tiedto the configuration device'sOE pin. Hence, the nSTATUSreset pulse also resets theconfiguration deviceautomatically. Once theFPGA releases nSTATUSand the configuration devicereleases its OE pin (which ispulled high), reconfigurationbegins.For more information on howlong the reset time-out periodis, see the appropriate devicefamily chapters.The device releases the tristateson its I/O pins beforereleasing the clear signal onits registers.Modified Configuration(Option On)The configuration processstops and to startreconfiguration the systemmust pulse nCONFIG fromhigh-to-low and back high.The device releases the clearsignals on its registers beforereleasing the tri-states. Thisoption allows the design tooperate before the devicedrives out, so all outputs donot start up low.Altera Corporation 6–5April 2007 Configuration Handbook, Volume 2