Configuration Handbook - Kamami.pl

Configuring Mercury, APEX 20K (2.5 V), ACEX 1K & FLEX 10K DevicesYou can cascade several EPC2 or EPC1 devices to configure multipleMercury, APEX 20K (2.5 V), ACEX 1K, and FLEX 10K devices. The firstconfiguration device in the chain is the master configuration device,while the subsequent devices are the slave devices. The masterconfiguration device sends DCLK to the Mercury, APEX 20K (2.5 V),ACEX 1K, and FLEX 10K devices and to the slave configuration devices.The first EPC device’s nCS pin is connected to the CONF_DONE pins of theFPGAs, while its nCASC pin is connected to nCS of the next configurationdevice in the chain. The last device’s nCS input comes from the previousdevice, while its nCASC pin is left floating. When all data from the firstconfiguration device is sent, it drives nCASC low, which in turn drivesnCS on the next configuration device. Because a configuration devicerequires less than one clock cycle to activate a subsequent configurationdevice, the data stream is uninterrupted.1 Enhanced configuration devices EPC4, EPC8, and EPC16 cannotbe cascaded.Since all nSTATUS and CONF_DONE pins are tied together, if any devicedetects an error, the master configuration device stops configuration forthe entire chain and the entire chain must be reconfigured. For example,if the master configuration device does not detect CONF_DONE going highat the end of configuration, it resets the entire chain by pulling its OE pinlow. This low signal drives the OE pin low on the slave configurationdevice(s) and drives nSTATUS low on all FPGAs, causing them to enter areset state. This behavior is similar to the FPGA detecting an error in theconfiguration data.Figure 8–7 shows how to configure multiple devices using cascadedEPC2 or EPC1 devices.Altera Corporation 8–17August 2005 Configuration Handbook, Volume 1