Configuring Cyclone II Devices
Figure 13–10. Multiple Device PS Configuration Using an External Host
Memory
V
(1)
V
(1)
V (2)
CC
CC
CC
V
V
CC
ADDR
DATA0
CC
10 kΩ
10 kΩ
10 kΩ
Cyclone II Device 1
MSEL1
Cyclone II Device 2
MSEL1
MSEL0
MSEL0
CONF_DONE
CONF_DONE
nSTATUS
nSTATUS
nCE
GND
GND
nCE
nCEO
External Host
(MAX II Device or
Microprocessor)
GND
nCEO
DATA0
N.C. (3)
DATA0
nCONFIG
DCLK
nCONFIG
DCLK
Notes to Figure 13–10:
(1) The pull-up resistor should be connected to a supply that provides an acceptable input signal for all devices in the
chain. VCC should be high enough to meet the VIH specification of the I/O on the devices and the external host.
(2) Connect the pull-up resistor to the VCCIO supply voltage of I/O bank that the nCEOpin resides in.
(3) The nCEOpin can be left unconnected or used as a user I/O pin when it does not feed another device’s nCEpin.
In multiple device PS configuration, connect the first Cyclone II device’s
nCEpin to GND and connect the nCEOpin to the nCEpin of the next
Cyclone II device in the chain. Use an external 10-kΩpull-up resistor to
pull the Cyclone II device’s nCEOpin high to its VCCIO level to help the
internal weak pull-up resistor when the nCEOpin feeds next Cyclone II
device's nCEpin. The input to the nCEpin of the last Cyclone II device in
the chain comes from the previous Cyclone II device. After the first
device completes configuration in a multiple device configuration chain,
its nCEOpin transitions low to activate the second device’s nCEpin,
which prompts the second device to begin configuration. The second
device in the chain begins configuration within one clock cycle.
Therefore, the MAX II device begins to transfer data to the next Cyclone II
device without interruption. The nCEOpin is a dual-purpose pin in
Cyclone II devices. You can leave the nCEOpin of the last device
unconnected or use it as a user I/O pin after configuration if the last
device in chain is a Cyclone II device.
1
The Quartus II software sets the Cyclone II device nCEOpin as a
dedicated output by default. If the nCEOpin feeds the next
device’s nCEpin, you must make sure that the nCEOpin is not
used as a user I/O after configuration. This software setting is in
the Dual-Purpose Pins tab of the Device & Pin Options dialog
box in Quartus II software.
Altera Corporation
February 2007
13–27
Cyclone II Device Handbook, Volume 1
ALTERA [ ALTERA CORPORATION ]
