EP2S180F1020C4 Datasheet, PDF (630/768 Pages) Altera Corporation – Stratix II Device Handbook, Volume 1

Passive Parallel Asynchronous Configuration
Figure 7–31 shows how to configure multiple Stratix II or Stratix II GX
devices using a microprocessor. This circuit is similar to the PPA
configuration circuit for a single device, except the devices are cascaded
for multi-device configuration.
Figure 7–31. Multi-Device PPA Configuration Using a Microprocessor
VCC (2)
(2) VCC
10 kΩ
Address Decoder
10 kΩ
ADDR
Memory
ADDR DATA[7..0]
VCC (2)
10 kΩ
Microprocessor
Stratix II Device 1
DATA[7..0]
nCS (1)
CS (1)
CONF_DONE
nSTATUS
nWS
nRS
nCONFIG
RDYnBSY
nCE
GND
DCLK
nCEO
MSEL3 _VCC
MSEL2
MSEL1
MSEL0
GND
VCC (2)
10 kΩ
Stratix II Device 2
DATA[7..0]
nCS (1)
CS (1)
CONF_DONE
nSTATUS
nCE
nWS
nRS
nCONFIG
RDYnBSY
DCLK
nCEO
MSEL3
MSEL2
MSEL1
MSEL0
N.C.
VCC
GND
Notes to Figure 7–31:
(1) If not used, the CS pin can be connected to V_CC directly. If not used, the nCS pin can be connected to GND directly.
(2) 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.
In multi-device PPA configuration the first device’s nCE pin is connected
to GND while its nCEO pin is connected to nCE of the next device in the
chain. The last device’s nCE input comes from the previous device, while
its nCEO pin is left floating. After the first device completes configuration
in a multi-device configuration chain, its nCEO pin drives low to activate
the second device’s nCE pin, which prompts the second device to begin
configuration. The second device in the chain begins configuration within
one clock cycle. Therefore, the transfer of data destinations is transparent
to the microprocessor.
Each device’s RDYnBSY pin can have a separate input to the
microprocessor. Alternatively, if the microprocessor is pin limited, all the
RDYnBSY pins can feed an AND gate and the output of the AND gate can
feed the microprocessor. For example, if you have two devices in a PPA
7–78
Stratix II Device Handbook, Volume 2
Altera Corporation
January 2008