9–66
Chapter 9: Configuration, Design Security, and Remote System Upgrades in the Cyclone III Device Family
Configuration Features
lists the dedicated configuration pins that must be connected properly on
your board for successful configuration. Some of these pins may not be required for
your configuration scheme.
Table 9–22. Dedicated Configuration Pins on Cyclone III Device Family (Part 1 of 4)
Pin Name
User
Mode
Configuration
Scheme
Pin Type
Description
4-bit configuration input that sets the Cyclone III device
family configuration scheme. These pins must be hardwired
to V
CCA
or GND. The
MSEL[3..0]
pins have internal 9-k
pull-down resistors that are always active.
Some of the smaller devices or package options of
Cyclone III devices do not have the
MSEL[3]
pin; therefore,
the AP configuration scheme is not supported.
Configuration control input. Pulling this pin low with external
circuitry during user mode causes the Cyclone III device
family to lose its configuration data, enter a reset state, and
tri-state all I/O pins. Returning this pin to a logic-high level
starts a reconfiguration.
The Cyclone III device family drives
nSTATUS
low
immediately after power-up and releases it after the POR
time.
■
MSEL [3..0]
N/A
All
Input
nCONFIG
N/A
All
Input
Status output. If an error occurs during configuration,
nSTATUS
is pulled low by the target device.
Status input. If an external source (for example, another
Cyclone III device family) drives the
nSTATUS
pin low
during configuration or initialization, the target device
enters an error state.
■
nSTATUS
N/A
All
Bidirectional
open-drain
Driving
nSTATUS
low after configuration and initialization
does not affect the configured device. If you use a
configuration device, driving
nSTATUS
low causes the
configuration device to attempt to configure the device, but
because the device ignores transitions on
nSTATUS
in user
mode, the device does not reconfigure. To start a
reconfiguration,
nCONFIG
must be pulled low.
■
Status output. The target Cyclone III device family drives
the
CONF_DONE
pin low before and during configuration.
After all configuration data is received without error and
the initialization cycle starts, the target device releases
CONF_DONE.
Status input. After all data is received and
CONF_DONE
goes high, the target device initializes and enters user
mode. The
CONF_DONE
pin must have an external 10-k
pull-up resistor in order for the device to initialize.
CONF_DONE
N/A
All
Bidirectional
open-drain
■
Driving
CONF_DONE
low after configuration and initialization
does not affect the configured device. Do not connect bus
holds or ADC to the
CONF_DONE
pin.
Cyclone III Device Handbook
Volume 1
August 2012 Altera Corporation
ALTERA [ ALTERA CORPORATION ]
