EP2S180F1020C4 Datasheet, PDF (582/768 Pages) Altera Corporation – Stratix II Device Handbook, Volume 1

Fast Passive Parallel Configuration
I/O pins will no longer have weak pull-up resistors and will function as
assigned in your design. The enhanced configuration device will drive
DCLK low and DATA[7..0] high at the end of configuration.
If an error occurs during configuration, the device drives its nSTATUS pin
low, resetting itself internally. Since the nSTATUS pin is tied to OE, the
configuration device will also be reset. If the Auto-restart configuration
after error option (available in the Quartus II software from the General
tab of the Device & Pin Options dialog box) is turned on, the device will
automatically initiate reconfiguration if an error occurs. The Stratix II or
Stratix II GX device releases its nSTATUS pin after a reset time-out period
(maximum of 100 µs). When the nSTATUS pin is released and pulled high
by a pull-up resistor, the configuration device reconfigures the chain. If
this option is turned off, the external system must monitor nSTATUS for
errors and then pulse nCONFIG low for at least 2 µs to restart
configuration. The external system can pulse nCONFIG if nCONFIG is
under system control rather than tied to V_CC.
In addition, if the configuration device sends all of its data and then
detects that CONF_DONE has not gone high, it recognizes that the device
has not configured successfully. Enhanced configuration devices wait for
64 DCLK cycles after the last configuration bit was sent for CONF_DONE to
reach a high state. In this case, the configuration device pulls its OE pin
low, which in turn drives the target device’s nSTATUS pin low. If the
Auto-restart configuration after error option is set in the software, the
target device resets and then releases its nSTATUS pin after a reset
time-out period (maximum of 100 µs). When nSTATUS returns to a logic
high level, the configuration device will try to reconfigure the device.
When CONF_DONE is sensed low after configuration, the configuration
device recognizes that the target device has not configured successfully.
Therefore, your system should not pull CONF_DONE low to delay
initialization. Instead, you should use the CLKUSR option to synchronize
the initialization of multiple devices that are not in the same
configuration chain. Devices in the same configuration chain will
initialize together if their CONF_DONE pins are tied together.
1
If the optional CLKUSR pin is used and nCONFIG is pulled low
to restart configuration during device initialization, ensure
CLKUSR continues toggling during the time nSTATUS is low
(maximum of 100 µs).
When the device is in user-mode, a reconfiguration can be initiated by
pulling the nCONFIG pin low. The nCONFIG pin should 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. Because CONF_DONE is
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Stratix II Device Handbook, Volume 2
Altera Corporation
January 2008