Configuration Handbook - Kamami.pl

Fast Passive Parallel ConfigurationI/O pins will no longer have weak pull-up resistors and will function asassigned in your design. The enhanced configuration device will driveDCLK low and DATA[7..0] high at the end of configuration.If an error occurs during configuration, the device drives its nSTATUS pinlow, resetting itself internally. Since the nSTATUS pin is tied to OE, theconfiguration device will also be reset. If the Auto-restart configurationafter error option (available in the Quartus II software from the Generaltab of the Device & Pin Options dialog box) is turned on, the device willautomatically initiate reconfiguration if an error occurs. The Stratix II orStratix II GX device releases its nSTATUS pin after a reset time-out period(maximum of 100 µs). When the nSTATUS pin is released and pulled highby a pull-up resistor, the configuration device reconfigures the chain. Ifthis option is turned off, the external system must monitor nSTATUS forerrors and then pulse nCONFIG low for at least 2 µs to restartconfiguration. The external system can pulse nCONFIG if nCONFIG isunder system control rather than tied to V CC .In addition, if the configuration device sends all of its data and thendetects that CONF_DONE has not gone high, it recognizes that the devicehas not configured successfully. Enhanced configuration devices wait for64 DCLK cycles after the last configuration bit was sent for CONF_DONE toreach a high state. In this case, the configuration device pulls its OE pinlow, which in turn drives the target device’s nSTATUS pin low. If theAuto-restart configuration after error option is set in the software, thetarget device resets and then releases its nSTATUS pin after a resettime-out period (maximum of 100 µs). When nSTATUS returns to a logichigh level, the configuration device will try to reconfigure the 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, you should use the CLKUSR option to synchronizethe initialization of multiple devices that are not in the sameconfiguration chain. Devices in the same configuration chain willinitialize together if their CONF_DONE pins are tied together.1 If the optional CLKUSR pin is used and nCONFIG is pulled lowto restart configuration during device initialization, ensureCLKUSR continues toggling during the time nSTATUS is low(maximum of 100 µs).When the device is in user-mode, a reconfiguration can be initiated bypulling the nCONFIG pin low. The nCONFIG pin should be low for at least2µs. When nCONFIG is pulled low, the device also pulls nSTATUS andCONF_DONE low and all I/O pins are tri-stated. Because CONF_DONE is7–30 Altera CorporationStratix II Device Handbook, Volume 2 May 2007