Configuration Handbook - Kamami.pl

Configuring Mercury, APEX 20K (2.5 V), ACEX 1K & FLEX 10K DevicesFigure 8–5. Software Settings for Daisy Chaining Two FPGAs on One DATA LineIn your system, you may have multiple devices that contain the sameconfiguration data. To support this configuration scheme, all device nCEinputs are tied to GND, while nCEO pins are left floating. All otherconfiguration pins (nCONFIG, nSTATUS, DCLK, DATA0, and CONF_DONE)are connected to every device in the chain. You should pay specialattention to the configuration signals because they can require bufferingto ensure signal integrity and prevent clock skew problems. Specifically,ensure that the DCLK and DATA lines are buffered for every fourth device.Devices must be the same density and package. All devices will start andcomplete configuration at the same time. Figure 8–6 shows multi-devicePS configuration when the Mercury, APEX 20K (2.5 V), ACEX 1K, andFLEX 10K devices are receiving the same configuration data.Altera Corporation 8–15August 2005 Configuration Handbook, Volume 1