Configuration Handbook - Kamami.pl

Fast Active Serial Configuration (Serial Configuration Devices)configuration. Once the option bit to enable INIT_DONE is programmedinto the device (during the first frame of configuration data), theINIT_DONE pin goes low. When initialization is complete, theINIT_DONE pin is released and pulled high. This low-to-high transitionsignals that the device has entered user mode. When initialization iscomplete, the device enters user mode. In user mode, the user I/O pinsno longer have weak pull-up resistors and function as assigned in yourdesign.If an error occurs during configuration, Stratix III devices assert thenSTATUS signal low, indicating a data frame error, and the CONF_DONEsignal stays low. If the Auto-restart configuration after error option(available in the Quartus II software from the General tab of the Deviceand Pin Options dialog box) is turned on, the Stratix III device resets theconfiguration device by pulsing nCSO, releases nSTATUS after a resettime-out period (maximum of 100 ms), and retries configuration. If thisoption is turned off, the system must monitor nSTATUS for errors andthen pulse nCONFIG low for at least 2 ms to restart configuration.When the Stratix III device is in user mode, you can initiatereconfiguration by pulling the nCONFIG pin low. The nCONFIG pinshould be low for at least 2 ms. When nCONFIG is pulled low, the devicealso pulls nSTATUS and CONF_DONE low and all I/O pins are tri-stated.Once nCONFIG returns to a logic high level and nSTATUS is released bythe Stratix III device, reconfiguration begins.You can configure multiple Stratix III devices using a single serialconfiguration device. You can cascade multiple Stratix III devices usingthe chip-enable (nCE) and chip-enable-out (nCEO) pins. The first device inthe chain must have its nCE pin connected to ground. You must connectits nCEO pin to the nCE pin of the next device in the chain. When the firstdevice captures all of its configuration data from the bitstream, it drivesthe nCEO pin low, enabling the next device in the chain. You must leavethe nCEO pin of the last device unconnected. The nCONFIG, nSTATUS,CONF_DONE, DCLK, and DATA0 pins of each device in the chain areconnected (refer to Figure 11–13).This first Stratix III device in the chain is the configuration master andcontrols configuration of the entire chain. You must connect its MSEL pinsto select the AS configuration scheme. The remaining Stratix III devicesare configuration slaves. You must connect their MSEL pins to select thePS configuration scheme. Any other Altera device that supports PSconfiguration can also be part of the chain as a configuration slave.Figure 11–13 shows the pin connections for this setup.11–34 Altera CorporationStratix III Device Handbook, Volume 1 May 2007