Altera Cyclone IV Device Handbook page 229

Chapter 8: Configuration and Remote System Upgrades in Cyclone IV Devices
Configuration
Table 8–20. Dedicated Configuration Pins on the Cyclone IV Device (Part 2 of 4)
Pin Name User Mode
N/A
CONF_DONE
N/A
nCE
N/A if
option is on.
nCEO
I/O if option
is off.
nCSO,
I/O
FLASH_nCE
(1)
May 2013 Altera Corporation
Configuration
Pin Type
Scheme
Bidirectional
All
open-drain
All Input
Output
All
open-drain
(2)
AS, AP Output
Description
Status output—the target Cyclone IV device drives the
■
CONF_DONE pin low before and during configuration.
After all the configuration data is received without error
and the initialization cycle starts, the target device
releases CONF_DONE.
Status input—after all the 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.
Driving CONF_DONE low after configuration and initialization
does not affect the configured device. Do not connect bus
holds or ADC to CONF_DONE pin.
Active-low chip enable. The nCE pin activates the Cyclone
IV device with a low signal to allow configuration. You must
hold nCE pin low during configuration, initialization, and
user-mode. In a single-device configuration, you must tie
the nCE pin low. In a multi-device configuration, nCE of the
first device is tied low while its nCEO pin is connected to
nCE of the next device in the chain. You must hold the nCE
pin low for successful JTAG programming of the device.
Output that drives low when configuration is complete. In a
single-device configuration, you can leave this pin floating
or use it as a user I/O pin after configuration. In a multi-
device configuration, this pin feeds the nCE pin of the next
device. The nCEO of the last device in the chain is left
floating or used as a user I/O pin after configuration.
If you use the nCEO pin to feed the nCE pin of the next
device, use an external 10-k pull-up resistor to pull the
nCEO pin high to the V voltage of its I/O bank to help the
CCIO
internal weak pull-up resistor.
If you use the nCEO pin as a user I/O pin after configuration,
set the state of the pin on the Dual-Purpose Pin settings.
Output control signal from the Cyclone IV device to the
serial configuration device in AS mode that enables the
configuration device. This pin functions as nCSO in AS
mode and FLASH_nCE in AP mode.
Output control signal from the Cyclone IV device to the
parallel flash in AP mode that enables the flash. Connects to
the CE# pin on the Micron P30 or P33 flash.
This pin has an internal pull-up resistor that is always
active.
8–65
(2)
Cyclone IV Device Handbook,
Volume 1