EP2C20F256C8N Datasheet, PDF (380/470 Pages) Altera Corporation – Cyclone II Device Handbook, Volume 1

PS Configuration
device also pulls nSTATUS and CONF_DONE low and tri-states all I/O
pins. Once the nCONFIG pin returns to a logic high level and the
Cyclone II device releases the nSTATUS pin, the MAX II device can begin
reconfiguration.
f
Error During Configuration
If an error occurs during configuration, the Cyclone II device transitions
its nSTATUS pin low, resetting itself internally. The low signal on the
nSTATUS pin tells the MAX II device that there is an error. If you turn on
the Auto-restart configuration after error option in the Quartus II
software, the Cyclone II device releases nSTATUS after a reset time-out
period (maximum of 40 µs). After nSTATUS is released and 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 MAX II device must monitor
the Cyclone II device's CONF_DONE pin to detect errors and determine
when programming completes. If all configuration data is sent, but
CONF_DONE or INIT_DONE do not transition high, the MAX II device
must reconfigure the target device.
For more information on configuration issues, see the Debugging
Configuration Problems chapter of the Configuration Handbook and the
FPGA Configuration Troubleshooter on the Altera web site
(www.altera.com).
Multiple Device PS Configuration Using a MAX II Device as an
External Host
Figure 13–10 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 Cyclone II devices are cascaded for multiple device
configuration.
13–26
Cyclone II Device Handbook, Volume 1
Altera Corporation
February 2007