
Altera Corporation
3–23
June 2006
Stratix Device Handbook, Volume 2
External Memory Interfaces in Stratix & Stratix GX Devices
Figure 3–12. DQ Configuration in Stratix & Stratix GX IOE
(1)
You can use the altdq megafunction to generate the DQ signals.
(2)
The OE signal is active low, but the Quartus II software implements this as active high and automatically adds an
inverter before the OE register AOE during compilation.
(3)
The outclock signal is phase shifted –90° from the system clock.
(4)
The shifted DQS signal must be inverted before going to the IOE. The inversion is automatic if you use the altdq
megafunction to generate the DQ signals.
D
Q
DFF
D
Q
LA
TCH
ENA
D
Q
DFF
Input Register AI
Input Register BI
Latch C
DQ
DFF
DQ
DFF
0
1
DQ
DFF
TRI
DQ Pin
OE Register AOE
Output Register AO
Output Register BO
Logic Array
Latch
dataout_l
dataout_h
outclock (3)
datain_h
datain_l
OE
inclock (from DQS bus)
neg_reg_out
I
(4)
(2)