Configuration Handbook - Kamami.pl

Fast Passive Parallel Configurationthe chain. The configuration signals may require buffering to ensuresignal integrity and prevent clock skew problems. Ensure that the DCLKand DATA lines are buffered for every fourth device. Because all deviceCONF_DONE pins are tied together, all devices initialize and enter usermode at the same time.All nSTATUS and CONF_DONE pins are tied together and if any devicedetects an error, configuration stops for the entire chain and the entirechain must be reconfigured. For example, if the first device flags an erroron nSTATUS, it resets the chain by pulling its nSTATUS pin low. Thisbehavior is similar to a single device detecting an error.If the Auto-restart configuration after error option is turned on, thedevices release their nSTATUS pins after a reset time-out period(maximum of 100 µs). After all nSTATUS pins are released and pulledhigh, the MAX II device can try to reconfigure the chain without pulsingnCONFIG low. If this option is turned off, the MAX II device mustgenerate a low-to-high transition (with a low pulse of at least 2 µs) onnCONFIG to restart the configuration process.In a multi-device FPP configuration chain, all Stratix II or Stratix II GXdevices in the chain must either enable or disable the decompressionand/or design security feature. You can not selectively enable thedecompression and/or design security feature for each device in thechain because of the DATA and DCLK relationship. If the chain containsdevices that do not support design security, you should use a serialconfiguration scheme.If a system has multiple devices that contain the same configuration data,tie all device nCE inputs to GND, and leave nCEO pins floating. All otherconfiguration pins (nCONFIG, nSTATUS, DCLK, DATA[7..0], andCONF_DONE) are connected to every device in the chain. Configurationsignals may require buffering to ensure signal integrity and prevent clockskew problems. Ensure that the DCLK and DATA lines are buffered forevery fourth device. Devices must be the same density and package. Alldevices start and complete configuration at the same time. Figure 7–5shows multi-device FPP configuration when both Stratix II orStratix II GX devices are receiving the same configuration data.7–20 Altera CorporationStratix II Device Handbook, Volume 2 May 2007