EP4SE360F35I4 Datasheet, PDF (364/432 Pages) Altera Corporation – This section provides a complete overview of all features relating to the Stratix IV device family, which is the most architecturlly advanced

10–28
Chapter 10: Configuration, Design Security, and Remote System Upgrades in Stratix IV Devices
Passive Serial Configuration
initialization is complete, the INIT_DONE pin is released and pulled high. The MAX II
device must be able to detect this low-to-high transition that signals the device has
entered user mode. When initialization is complete, the device enters user mode. In
user-mode, the user I/O pins no longer have weak pull-up resistors and function as
assigned in your design.
1 Two DCLK falling edges are required after CONF_DONE goes high to begin the
initialization of the device for both uncompressed and compressed bitstream in PS.
To ensure DCLK and DATA0 are not left floating at the end of configuration, the MAX II
device must drive them either high or low, whichever is convenient on your board.
The DATA[0] pin is available as a user I/O pin after configuration. When you chose the
PS scheme as a default in the Quartus II software, this I/O pin is tri-stated in user
mode and must be driven by the MAX II device. To change this default option in the
Quartus II software, select the Dual-Purpose Pins tab of the Device and Pin Options
dialog box.
The configuration clock (DCLK) speed must be below the specified frequency to ensure
correct configuration. No maximum DCLK period exists, which means you can pause
the configuration by halting DCLK for an indefinite amount of time.
If an error occurs during configuration, the device drives its nSTATUS pin low, resetting
itself internally. The low signal on the nSTATUS pin also alerts the MAX II device that
there is an error. If the Auto-restart configuration after error option (available in the
Quartus II software from the General tab of the Device and Pin Options dialog box)
is turned on, the Stratix IV device releases nSTATUS after a reset time-out period (a
maximum of 500 s). 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 s) on nCONFIG to restart the
configuration process.
1 If you have enabled the Auto-restart configuration after error option, the nSTATUS pin
transitions from high to low and back again to high when a configuration error is
detected. This appears as a low pulse at the nSTATUS pin with a minimum pulse width
of 10 s to a maximum pulse width of 500 s, as defined in the t_STATUS specification.
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 you use the optional CLKUSR pin and nCONFIG is pulled low to restart configuration
during device initialization, you must ensure that CLKUSR continues toggling during
the time nSTATUS is low (a maximum of 500 s).
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 s. When
nCONFIG is pulled low, the device also pulls nSTATUS and CONF_DONE low and all I/O
pins are tri-stated. After nCONFIG returns to a logic high level and nSTATUS is released
by the device, reconfiguration begins.
Stratix IV Device Handbook
Volume 1
September 2012 Altera Corporation