EP2S130F1020I4 Datasheet, PDF (602/768 Pages) List of Unclassifed Manufacturers – Stratix II Device Handbook, Volume 1

Passive Serial Configuration
pulled high by a pull-up resistor, the MAX II device can try to reconfigure
the target device without needing to pulse nCONFIG low. If this option is
turned off, the MAX II device must generate a low-to-high transition
(with a low pulse of at least 2 µs) on nCONFIG to restart the configuration
process.
The MAX II device can also monitor the CONF_DONE and INIT_DONE
pins to ensure successful configuration. The CONF_DONE pin must be
monitored by the MAX II device to detect errors and determine when
programming completes. If all configuration data is sent, but CONF_DONE
or INIT_DONE have not gone high, the MAX II device must reconfigure
the target device.
1
If the optional CLKUSR pin is being used and nCONFIG is pulled
low to restart configuration during device initialization, you
need to ensure that CLKUSR continues toggling during the time
nSTATUS is low (maximum of 100 µs).
When the device is in user-mode, you can initiate a reconfiguration by
transitioning the nCONFIG pin low-to-high. The nCONFIG pin must be
low for at least 2 µs. When nCONFIG is pulled low, the device also 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 by the
device, reconfiguration begins.
Figure 7–18 shows how to configure multiple devices using a MAX II
device. This circuit is similar to the PS configuration circuit for a single
device, except Stratix II or Stratix II GX devices are cascaded for
multi-device configuration.
7–50
Stratix II Device Handbook, Volume 2
Altera Corporation
January 2008