EP2S90F1020C5 Datasheet, PDF (618/768 Pages) Altera Corporation – Stratix II Device Handbook, Volume 1

Passive Serial Configuration
Figure 7–25 shows how to configure multiple devices using cascaded
EPC2 devices.
Figure 7–25. Multi-Device PS Configuration Using Cascaded EPC2 Devices
VCC (1)
VCC (1)
VCC (1)
(3) 10 kΩ 10 kΩ (2) 10 kΩ (3)
Stratix II Device 2
MSEL3
DCLK
VCC
MSEL2
DATA0
nSTATUS
MSEL1 _{CONF_DONE}
MSEL0
nCONFIG
GND ^{N.C. nCEO}
nCE
VCC
GND
Stratix II Device 1
MSEL3
MSEL2
MSEL1
MSEL0
DCLK
DATA0
nSTATUS
CONF_DONE
nCONFIG
nCEO
nCE
GND
EPC2/EPC1
Device 1
DCLK
DATA
OE (3)
nCS (3) nCASC
nINIT_CONF (2)
EPC2/EPC1
Device 2
DCLK
DATA
nCS
OE
nINIT_CONF
Notes to Figure 7–25:
(1) The pull-up resistor should be connected to the same supply voltage as the configuration device.
(2) The nINIT_CONF pin (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_CONF-nCONFIG line. The nINIT_CONF pin does not need to be connected if its functionality is not used.
(3) The enhanced configuration devices’ and EPC2 devices’ OE and nCS pins have internal programmable pull-up
resistors. External 10-kpull-up resistors should be used. To turn off the internal pull-up resistors, check the
Disable nCS and OE pull-ups on configuration device option when generating programming files.
When using enhanced configuration devices or EPC2 devices, nCONFIG
of the device can be connected to nINIT_CONF of the configuration
device, allowing the INIT_CONF JTAG instruction to initiate device
configuration. The nINIT_CONF pin does not need to be connected if its
functionality is not used. An internal pull-up resistor on the nINIT_CONF
pin is always active in the enhanced configuration devices and the EPC2
devices, which means that you shouldn’t be using an external pull-up
resistor if nCONFIG is tied to nINIT_CONF. If you are using multiple
EPC2 devices to configure a Stratix II or Stratix II GX device(s), only the
first EPC2 has its nINIT_CONF pin tied to the device’s nCONFIG pin.
You can use a single configuration chain to configure Stratix II or
Stratix II GX devices with other Altera devices. To ensure that all devices
in the chain complete configuration at the same time or that an error
flagged by one device initiates reconfiguration in all devices, all of the
device CONF_DONE and nSTATUS pins must be tied together.
7–66
Stratix II Device Handbook, Volume 2
Altera Corporation
January 2008