nCASC pin is used to cascade configuration devices to configure large APEXTM and FLEXTM devices. The
nCASC pin is driven low when the configuration device's internal address counter reaches its maximum value (when the last bit of the configuration data is sent to the APEX or FLEX device). The internal address counter can only be incremented by the
DCLK signal when the
nCS pin is low. If you only use one configuration device, the
nCS pin is pulled high by the
CONF_DONE signal before the device's internal address counter reaches its maximum value. In this case, the
nCASC pin is not driven low.
To tell when configuration is complete, see the
init_done pin of the FLEX or APEX device.
|For more information on all configuration signals, refer to the Configuration Handbook.|