Altera ALTDLL - Manual (Page 47)

4–11 Chapter 4: Functional Description
ALTDQ_DQS Megafunction
ALTDLL and ALTDQ_DQS Megafunctions User Guide © February 2012 Altera Corporation
The DQ output and OE path consist of the following blocks:
Table 4–5. DQ Output and OE Path
Block Name Description
<IO> _OUTPUT_FF DQ output
register blocks Sends data directly to the external memory DQ pins
during a write operation through the output buffer. These
blocks are clocked by the DQ write clock.
The <IO> _OUTPUT_FF block represents a group of
flip-flop registers in the DQ output path.
The <IO> _OUTPUT_DDIO_OUT represents a group of
double data rate output registers in the DQ output path.
<IO> _OUTPUT_DDIO_OUT
<IO> _OE_FF DQ output enable
register blocks Sends output enable signal to the output buffer. These
blocks are clocked by the DQ write clock.
The <IO> _OE_FF block represents a group of flip-flop
registers in the DQ OE path.
The <IO> _OE_DDIO_OE represents a group of double
data rate registers in the DQ OE path.
<IO> _OE_DDIO_OE
<IO> _OUTPUT_HR_DDIO_OUT_HIGH
and
<IO> _OUTPUT_HR_DDIO_OUT_LOW
Half-rate output
register block Represents the DDIO registers that are used to transfer
DQ signals from the core during half-rate write operation.
These blocks are clocked by the DQ write clock.
<IO> _OE_HR_DDIO_OUT Half-rate output
enable register
block Represents the DDIO registers that are used to transfer
half-rate DQ output enable signals to the output buffer.
<IO> _OUTPUT_DELAY_CHAIN1 (D5) DQ output delay
chains For more information about the DQ output and OE delay
chains, refer to
Table 4–2 on page 4–4 .
<IO> _OUTPUT_DELAY_CHAIN2 (D6)
<IO> _OE_DELAY_CHAIN1 (D5) DQ OE delay
chains
<IO> _OE_DELAY_CHAIN2 (D6)
IO_CONFIG I/O Configuration
Block For more information about the IO_CONFIG block, refer
to Table 4–2 on page 4–4 .