EP2S180F1020C4 Datasheet, PDF (604/768 Pages) Altera Corporation – Stratix II Device Handbook, Volume 1

Passive Serial Configuration
If the Auto-restart configuration after error option is turned on, the
devices release their nSTATUS pins after a reset time-out period
(maximum of 100 µs). After all nSTATUS pins are released and pulled
high, the MAX II device can try to reconfigure the chain without needing
to pulse nCONFIG low. If this option is turned off, the MAX II device must
generate a low-to-high transition (with a low pulse of at least 2 µs) on
nCONFIG to restart the configuration process.
In your system, you can have multiple devices that contain the same
configuration data. To support this configuration scheme, all device nCE
inputs are tied to GND, while nCEO pins are left floating. All other
configuration pins (nCONFIG, nSTATUS, DCLK, DATA0, and CONF_DONE)
are connected to every device in the chain. Configuration signals can
require buffering to ensure signal integrity and prevent clock skew
problems. Ensure that the DCLK and DATA lines are buffered for every
fourth device. Devices must be the same density and package. All devices
will start and complete configuration at the same time. Figure 7–19 shows
multi-device PS configuration when both Stratix II or Stratix II GX
devices are receiving the same configuration data.
Figure 7–19. Multiple-Device PS Configuration When Both devices Receive the Same Data
Memory
ADDR
DATA0
VCC (1) VCC (1)
10 k Ω 10 k Ω
Stratix II Device
Stratix II Device
External Host
(MAX II Device or
Microprocessor)
GND
CONF_DONE
nSTATUS
nCE
nCEO
MSEL3
DATA0
nCONFIG
DCLK
MSEL2
MSEL1
MSEL0
N.C. (2)
V_CC
GND
CONF_DONE
nSTATUS
nCEO
nCE
MSEL3
DATA0
nCONFIG
DCLK
MSEL2
MSEL1
MSEL0
N.C. (2)
V_CC
GND
GND
Notes to Figure 7–19:
(1) The pull-up resistor should be connected to a supply that provides an acceptable input signal for all devices in the
chain. V_CC should be high enough to meet the V_IH specification of the I/O on the device and the external host.
(2) The nCEO pins of both devices are left unconnected when configuring the same configuration data into multiple
devices.
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.
7–52
Stratix II Device Handbook, Volume 2
Altera Corporation
January 2008