EP2S180F1020C4 Datasheet, PDF (592/768 Pages) Altera Corporation – Stratix II Device Handbook, Volume 1

Active Serial Configuration (Serial Configuration Devices)
Figure 7–13. Multi-Device AS Configuration
V_CC (1) V_CC (1) V_CC (1)
10 kΩ 10 kΩ 10 kΩ
Serial Configuration
Device
DATA
DCLK
nCS
ASDI
Stratix II or Stratix II GX
FPGA Master
nSTATUS
CONF_DONE
nCONFIG
nCE
nCEO
V_CC
GND
DATA0
DCLK
nCSO
ASDO
(2) MSEL3
(2) MSEL2
(2) MSEL1
(2) MSEL0
GND
Stratix II or Stratix II GX
FPGA Slave
nSTATUS
CONF_DONE nCEO
N.C.
nCONFIG
nCE
DATA0
MSEL3
V_CC
MSEL2
DCLK
MSEL1
MSEL0
GND
Notes to Figure 7–13:
(1) Connect the pull-up resistors to a 3.3-V supply.
(2) If using an EPCS4 device, MSEL[3..0] should be set to 1101. Refer to Table 7–11 for more details.
As shown in Figure 7–13, the nSTATUS and CONF_DONE pins on all target
devices are connected together with external pull-up resistors. These pins
are open-drain bidirectional pins on the devices. When the first device
asserts nCEO (after receiving all of its configuration data), it releases its
CONF_DONE pin. But the subsequent devices in the chain keep this shared
CONF_DONE line low until they have received their configuration data.
When all target devices in the chain have received their configuration
data and have released CONF_DONE, the pull-up resistor drives a high
level on this line and all devices simultaneously enter initialization mode.
If an error occurs at any point during configuration, the nSTATUS line is
driven low by the failing device. If you enable the Auto-restart
configuration after error option, reconfiguration of the entire chain begins
after a reset time-out period (a maximum of 100 µs). If the Auto-restart
configuration after error option is turned off, the external system must
monitor nSTATUS for errors and then pulse nCONFIG low to restart
configuration. The external system can pulse nCONFIG if it is under
system control rather than tied to V_CC.
1 While you can cascade Stratix II or Stratix II GX devices, serial
configuration devices cannot be cascaded or chained together.
7–40
Stratix II Device Handbook, Volume 2
Altera Corporation
January 2008