Altera Corporation 11–9
July 2005 Stratix Device Handbook, Volume 2
Configuring Stratix & Stratix GX Devices
If this option is turned off, the external system must monitor nSTATUS for
errors and then pulse nCONFIG low to restart configuration. The external
system can pulse nCONFIG if it is under system control rather than tied to
V
CC
. When configuration is complete, the target device releases
CONF_DONE, which disables the configuration device by driving nCS
high. The configuration device drives DCLK low before and after
configuration.
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 target
device has not configured successfully. In this case, the configuration
device pulses its OE pin low for a few microseconds, driving the target
device’s nSTATUS pin low. If the Auto-Restart Configuration on Frame
Error option is set in the software, the target device resets and then pulses
its nSTATUS pin low. When nSTATUS returns high, the configuration
device reconfigures the target device. When configuration is complete,
the configuration device drives DCLK low.
Do not pull CONF_DONE low to delay initialization. Instead, use the
Quartus II software’s Enable User-Supplied Start-Up Clock (CLKUSR)
option to synchronize the initialization of multiple devices that are not in
the same configuration chain. Devices in the same configuration chain
initialize together. When CONF_DONE is driven low after device
configuration, the configuration device recognizes that the target device
has not configured successfully.
Figure 11–2 shows how to configure one Stratix or Stratix GX device with
one configuration device.
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