EP3C16F256I7N Altera, EP3C16F256I7N Datasheet - Page 155

• Manufacturer Part Number: EP3C16F256I7N
• Description: Cyclone III
• Manufacturer: Altera

Chapter 8: External Memory Interfaces in the Cyclone III Device Family
Cyclone III Device Family Memory Interfaces Features
Figure 8–4. Cyclone III Device Family DDR Input Registers
© January 2010 Altera Corporation
dataout_h
dataout_l
Figure 8–4
The DDR data is first fed to two registers, input register A
■
■
■
The data from the DDR input register is fed to two registers, sync_reg_h and
sync_reg_l, then the data is typically transferred to a FIFO block to synchronize the
two data streams to the rising edge of the system clock. Because the read-capture
clock is generated by the PLL, the read-data strobe signal (DQS or CQ) is not used
during read operation in Cyclone III device family; hence, postamble is not a concern
in this case.
Input register A
Input register B
Register C
shows Cyclone III device family DDR input registers.
I
aligns the data before it is synchronized with the system clock
I
I
captures the DDR data present during the falling edge of the clock
captures the DDR data present during the rising edge of the clock
DDR Input Registers in Cyclone III Device Family
Register C
Register
LE
I
Input Register A
Input Register B
neg_reg_out
Register
Register
LE
LE
I
I
Capture Clock
Cyclone III Device Handbook, Volume 1
I
and input register B
PLL
DQ
I
.
8–11