Configuration Handbook - Kamami.pl

Active Serial Configuration (Serial Configuration Devices)Figure 7–13. Multi-Device AS Configuration(1) V CC (1) V CC (1)10 kΩ10 kΩ10 kΩSerial ConfigurationDeviceStratix II or Stratix II GXFPGA MasternSTATUSCONF_DONEStratix II or Stratix II GXFPGA SlavenSTATUSCONF_DONEnCEON.C.nCEV CCnCONFIG nCONFIGnCEOV CCnCEDATADCLKnCSASDIGNDDATA0DCLKnCSOASDO(2) MSEL3MSEL3DATA0(2) MSEL2MSEL2DCLK(2) MSEL1MSEL1(2) MSEL0MSEL0V CCGNDGNDNotes to Figure 7–13:(1) Connect the pull-up resistors to a 3.3-V supply.(2) If using an EPCS4 device, MSEL[3..0] should be set to 1101. Refer to Table 7–11 for more details.As shown in Figure 7–13, the nSTATUS and CONF_DONE pins on all targetdevices are connected together with external pull-up resistors. These pinsare open-drain bidirectional pins on the devices. When the first deviceasserts nCEO (after receiving all of its configuration data), it releases itsCONF_DONE pin. But the subsequent devices in the chain keep this sharedCONF_DONE line low until they have received their configuration data.When all target devices in the chain have received their configurationdata and have released CONF_DONE, the pull-up resistor drives a highlevel on this line and all devices simultaneously enter initialization mode.If an error occurs at any point during configuration, the nSTATUS line isdriven low by the failing device. If you enable the Auto-restartconfiguration after error option, reconfiguration of the entire chain beginsafter a reset time-out period (a maximum of 100 µs). If the Auto-restartconfiguration after error option is turned off, the external system mustmonitor nSTATUS for errors and then pulse nCONFIG low to restartconfiguration. The external system can pulse nCONFIG if it is undersystem control rather than tied to V CC .1 While you can cascade Stratix II or Stratix II GX devices, serialconfiguration devices cannot be cascaded or chained together.7–40 Altera CorporationStratix II Device Handbook, Volume 2 May 2007