Configuration Handbook - Kamami.pl

Configuring Cyclone FPGAsCONF_DONE goes high during the first few clock cycles of initialization.Hence, when using the CLKUSR feature you would not see theCONF_DONE signal high until you start clocking CLKUSR. However, thedevice does retain configuration data and waits for these initializationclocks to release CONF_DONE and go into user mode. Figure 13–11shows how to configure one Cyclone FPGA with one configurationdevice.Figure 13–11. Single Device Configuration CircuitV CC (1)V CC (1) V CC (1)V CC (4)nCONFIGCyclone FPGA10 kΩ 10 kΩ 10 kΩDCLKDATA0nSTATUSCONF_DONEMSEL0nCEO N.C. (3)MSEL1nCEConfigurationDeviceDCLKDATAOEnCSnINIT_CONF (2)GNDGNDNotes to Figure 13–11:(1) The pull-up resistor should be connected to the same supply voltage as theconfiguration device. This pull-up resistor is 10 kΩ. The EPC16, EPC8, EPC4, andEPC2 devices’ OE and nCS pins have internal, user-configurable pull-up resistors.If you use internal pull-up resistors, do not use external pull-up resistors on thesepins.(2) The nINIT_CONF pin is available on EPC16, EPC8, EPC4, and EPC2 devices andhas an internal pull-up resistor that is always active. If nINIT_CONF is not used,nCONFIG can be pulled to V CC directly or through a resistor.(3) The nCEO pin is left unconnected for the last device in the chain.(4) Connect MSEL0 to the V CC supply voltage of the I/O bank it resides in.Configuring Multiple Cyclone FPGAsYou can use a single configuration device to configure multiple CycloneFPGAs. In this setup, the nCEO pin of the first device is connected to thenCE pin of the second device in the chain. If there are additional devices,connect the nCE pin of the next device to the nCEO pin of the previousdevice. You should leave the nCEO pin on the last device in the chainunconnected. To configure properly, all of the target device CONF_DONEand nSTATUS pins must be tied together. Figure 13–12 shows an exampleof configuring multiple Cyclone FPGAs using a single configurationdevice.Altera Corporation 13–21January 2007 Cyclone Device Handbook, Volume 1