Configuration Handbook - Kamami.pl

Passive Serial ConfigurationIf 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 needingto pulse nCONFIG 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 your system, you can 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. Configuration signals canrequire buffering to ensure signal integrity and prevent clock skewproblems. Ensure that the DCLK and DATA lines are buffered for everyfourth device. Devices must be the same density and package. All deviceswill start and complete configuration at the same time. Figure 7–19 showsmulti-device PS configuration when both Stratix II or Stratix II GXdevices are receiving the same configuration data.Figure 7–19. Multiple-Device PS Configuration When Both devices Receive the Same DataMemoryADDRDATA0VCC (1)VCC (1)10 kΩ 10 kΩStratix II DeviceStratix II DeviceExternal Host(MAX II Device orMicroprocessor)GNDCONF_DONEnSTATUSnCEnCEOMSEL3MSEL2DATA0nCONFIG MSEL1DCLK MSEL0N.C. (2)V CCGNDCONF_DONEnSTATUS nCEOnCEMSEL3MSEL2DATA0nCONFIGMSEL1DCLK MSEL0N.C. (2)V CCGNDGNDNotes to Figure 7–19:(1) The pull-up resistor should be connected to a supply that provides an acceptable input signal for all devices in thechain. V CC should be high enough to meet the V IH specification of the I/O on the device and the external host.(2) The nCEO pins of both devices are left unconnected when configuring the same configuration data into multipledevices.You can use a single configuration chain to configure Stratix II orStratix II GX devices with other Altera devices. To ensure that all devicesin the chain complete configuration at the same time or that an errorflagged by one device initiates reconfiguration in all devices, all of thedevice CONF_DONE and nSTATUS pins must be tied together.7–52 Altera CorporationStratix II Device Handbook, Volume 2 May 2007