PS Configuration
Figure 13–17. Multiple Device PS Configuration Using Cascaded EPC2 or EPC1 Devices
(4)
V
V
(1)
CC
CC
V
V
CC
(1)
(1)
CC
10 kΩ
(3) 10 kΩ 10 kΩ (2)
10 kΩ (3)
V
V
CC
CC
EPC2 or EPC1
Device 1
DCLK
DATA
OE (3)
EPC2 or EPC1
Device 2
Cyclone II Device 2
DCLK
Cyclone II Device 1
DCLK
DATA0
nSTATUS
MSEL0
MSEL1
MSEL0
DATA0
DCLK
DATA
nCS
OE
MSEL1
nSTATUS
CONF_DONE
nCONFIG
CONF_DONE
nCONFIG
(3)
nCS
nINIT_CONF (2)
nCASC
GND
N.C.
GND
nINIT_CONF
nCE
(5)
nCEO
nCE
nCEO
GND
Notes to Figure 13–17:
(1) The pull-up resistor should be connected to the same supply voltage as the configuration device.
(2) The nINIT_CONFpin (available on enhanced configuration devices and EPC2 devices only) 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_CONF
is not used or not available (e.g., on EPC1 devices), nCONFIGmust be pulled to VCC either directly or through a
resistor (if reconfiguration is required, a resistor is necessary).
(3) The enhanced configuration devices’ and EPC2 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) Use an external 10-kΩpull-up resistor to pull the nCEOpin high to the I/O bank VCCIO level to help the internal
weak pull-up when it feeds next device’s nCEpin.
(5) The nCEOpin can be left unconnected or used as a user I/O pin when it does not feed other device’s nCEpin.
When using enhanced configuration devices or EPC2 devices, you can
connect the Cyclone II device’s nCONFIGpin to the configuration
device’s nINIT_CONFpin, which allows the INIT_CONFJTAG
instruction to initiate FPGA configuration. You do not need to connect the
nINIT_CONFpin if it is not used. If the nINIT_CONFpin is not used or
not available (for example, on EPC1 devices), pull the nCONFIGpin to
VCC levels 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 the enhanced configuration devices
and the EPC2 devices. Therefore, do not use an external pull-up resistor
if you connect the nCONFIGpin to nINIT_CONF. If you use multiple
EPC2 devices to configure a Cyclone II device(s), only connect the first
EPC2 device’s nINIT_CONFpin to the device's nCONFIGpin.
13–46
Altera Corporation
February 2007
Cyclone II Device Handbook, Volume 1
ALTERA [ ALTERA CORPORATION ]
