Configuring Cyclone II Devices
Figure 13–13. Single Device PS Configuration Using an Enhanced
Configuration Device
V
V
(1)
V
CC
(1)
(1)
CC
CC
Enhanced
Configuration
Device
10 kΩ
10 kΩ
10 kΩ
Cyclone II FPGA
DCLK
DATA
DCLK
DATA0
OE (3)
nSTATUS
CONF_DONE
nCONFIG
nCS (3)
nINIT_CONF (2)
V
CC
nCEO
nCE
N.C. (4)
MSEL0
MSEL1
GND
GND
Notes to Figure 13–13:
(1) The pull-up resistor should be connected to the same supply voltage as the
configuration device. This pull-up resistor is 10 kΩ.
(2) The nINIT_CONFpin is available on enhanced configuration devices and has an
internal pull-up resistor that is always active, meaning an external pull-up resistor
should not be used on the nINIT_CONFto nCONFIGline. The nINIT_CONFpin
does not need to be connected if its functionality is not used. If nINIT_CONFis not
used, nCONFIGmust be pulled to VCC either directly or through a resistor (if
reconfiguration is required, a resistor is necessary).
(3) The enhanced configuration devices’ OEand nCSpins have internal
programmable pull-up resistors. If internal pull-up resistors are used, external
pull-up resistors should not be used on these pins. The internal pull-up resistors
are used by default in the Quartus II software. To turn off the internal pull-up
resistors, check the Disable nCS and OE pull-ups on configuration device option
when generating programming files.
(4) The nCEOpin can be left unconnected or used as a user I/O pin when it does not
feed other device’s nCEpin.
f
The value of the internal pull-up resistors on the enhanced configuration
devices and EPC2 devices can be found in the Enhanced Configuration
Devices (EPC4, EPC8, & EPC16) Data Sheet or the Configuration Devices for
SRAM-based LUT Devices Data Sheet.
When using enhanced configuration devices or EPC2 devices, you can
connect the Cyclone II nCONFIGpin to the configuration device
nINIT_CONFpin, which allows the INIT_CONFJTAG instruction to
initiate FPGA configuration. You do not need to connect the
nINIT_CONFpin if you are not using it. If nINIT_CONFis not used or not
available (e.g., on EPC1 devices), pull the nCONFIGsignal to VCC either
directly or through a resistor (if reconfiguration is required, a resistor is
necessary). An internal pull-up resistor on the nINIT_CONFpin is always
active in enhanced configuration devices and EPC2 devices. Therefore,
you do not need an external pull-up if nCONFIGis connected to
nINIT_CONF.
Altera Corporation
February 2007
13–33
Cyclone II Device Handbook, Volume 1
ALTERA [ ALTERA CORPORATION ]
