Altera ALTDLL - Manual (Page 108)

A–7
Clear Box Generator Options
© February 2012 Altera Corporation ALTDLL and ALTDQ_DQS Megafunctions User Guide
USE_DQS_DELAY_CHAIN_
PHASECTRLIN
OptionalO FALSE FALSE, TRUE This parameter is the signal used to
choose the phase applied to the
dqsbusout output when
is set to TRUE ;
otherwise, the phase setting is
determined by the
parameter. Only feed this port by the
dqsinputphasesetting output
port of the DQS config. You must
connect this port if
is set to
TRUE ; otherwise, this port is
optional and defaults to GND . This
input must match the polarity of its
source and cannot be inverted.
DQS_DELAY_CHAIN_PHASE_
SETTING
Optional 0 0, 1, 2, 3, 4 This parameter is a delay chain setting.
If is set to
FALSE ,
this parameter sets the number of DQS
delay buffers that the
dqsin signal
should travel through to the
dqsbusout port; otherwise, you can
ignore this setting. When it is set to 0 ,
the dqsbusout signal bypasses the
DQS delay chain. When it is set to 1 , 2 ,
3 , or 4 , the dqsbusout signal goes
through 1, 2, 3, or 4 delay buffers,
respectively, that are controlled by
delayctrlin[5..0] . The
phase-shift implemented is determined
by the ratio of the DQS delay buffers to
DLL delay buffers: phase_shift =
phase_setting/DLL delay_chain_length
* 360
DELAY_BUFFER_MODE Optional LOW LOW, HIGH This parameter determines whether the
variable delay buffers are working in
low-frequency mode or high-frequency
mode.
DQS_PHASE_SHIFT Optional 0 0..36,000 This parameter indicates the phase
shift between the delayed DQS signal
and the input DQS signal in units of
hundreds of degrees (for example, a
90° phase shift is represented as
9,000). This parameter is applicable
only for static timing analysis because
the phase shift through the
delayctrlin[5..0] ,
phasectrlin[2..0] , and
offsetctrlin[5..0] ports
cannot be determined.
DQS_OFFSETCTRL_ENABLE Optional FALSE FALSE, TRUE This parameter describes whether the
offsetctrlin[5..0] inputs are
used.
Table A–3. Megafunction Parameters to Configure DQS Input Path (Part 2 of 4)
Parameter Name
Optional/
Required Default Legal Values Description