EP3C16F256I7N Altera, EP3C16F256I7N Datasheet - Page 258

• Manufacturer Part Number: EP3C16F256I7N
• Description: Cyclone III
• Manufacturer: Altera

Configuring Cyclone III Devices
10–22
Cyclone III Device Handbook, Volume 1
As shown in
devices are connected together with external pull-up resistors. These pins
are open-drain bidirectional pins on the devices. When the first device
asserts nCEO (after receiving all of its configuration data), it releases its
CONF_DONE pin. However, the subsequent devices in the chain keep this
shared CONF_DONE line low until they have received their configuration
data. When all target devices in the chain have received their
configuration data and have released CONF_DONE, the pull-up resistor
drives a high level on this line and all devices simultaneously enter
initialization mode.
If an error occurs at any point during configuration, the nSTATUS line is
driven low by the failing device. If you enable the Auto-restart
configuration after error option, reconfiguration of the entire chain
begins after a reset time-out period (a maximum of 80 µs). If the
Auto-restart configuration after error 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
1
If the configuration bitstream size exceeds the capacity of a serial
configuration device, you must select a larger configuration device
and/or enable the compression feature. When configuring multiple
devices, the size of the bitstream is the sum of the individual devices'
configuration bitstreams.
Configuring Multiple Cyclone III Devices with the Same Design
Certain designs require you to configure multiple Cyclone III devices
with the same design through a configuration bitstream or SOF. You can
do this through one of two methods, as described in this section. For both
methods, the serial configuration devices cannot be cascaded or chained
together.
Multiple SRAM Object Files
In the first method, two copies of the SRAM Object File (.sof) are stored
in the serial configuration device. Use the first copy to configure the
master Cyclone III device and the second copy to configure all remaining
slave devices concurrently. All slave devices must be the same density
and package. The setup is similar to
up in active serial mode and the slave devices are set up in passive serial
mode.
While you can cascade Cyclone III devices, serial configuration
devices cannot be cascaded or chained together.
Figure
10–4, the nSTATUS and CONF_DONE pins on all target
Figure 10–4
CCIO
Altera Corporation-Preliminary
.
where the master is set
March 2007