XC3S502 Xilinx Corp., XC3S502 Datasheet - Page 39

• Manufacturer Part Number: XC3S502
• Description: Spartan-3 Fpga Family Complete Data Sheet
• Manufacturer: Xilinx Corp.

Table 19: PS Attributes
DS099-2 (v2.2) May 25, 2007
Product Specification
Notes:
1.
CLKOUT_PHASE_SHIFT
PHASE_SHIFT
Notes:
1.
2.
The practical range of values will be less when T
(FINE_SHIFT_RANGE)/2 in the Variable Phase mode. the FINE_SHIFT_RANGE represents the sum total delay of all taps.
P represents the integer value ranging from –255 to +255 to which the PHASE_SHIFT attribute is assigned.
N is an integer value ranging from –255 to +255 that represents the net phase shift effect from a series of increment and/or
decrement operations.
N = {Total number of increments} – {Total number of decrements}
A positive value for N indicates a net increment; a negative value indicates a net decrement.
Attribute
a. CLKOUT_PHASE_SHIFT = NONE
b. CLKOUT_PHASE_SHIFT = FIXED
c. CLKOUT_PHASE_SHIFT = VARIABLE
R
Shift Range over all P Values:
Shift Range over all P Values:
Shift Range over all N Values:
Disables PS component or chooses between Fixed Phase
and Variable Phase modes.
Determines size and direction of initial fine phase shift.
CLKFB before
CLKFB after
Decrement
Decrement
CLKIN
CLKFB
CLKIN
CLKFB
CLKIN
Figure 21: Phase Shifter Waveforms
CLKIN
–255
–255
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Description
> FINE_SHIFT_RANGE in the Fixed Phase mode, also when T
–255
Spartan-3 FPGA Family: Functional Description
0
0
256
256
P
P
256
N
* T
* T
* T
CLKIN
CLKIN
CLKIN
0
NONE, FIXED, VARIABLE
+255
+255
Integers from –255 to +255
DS099-2_11_031303
Values
+255
CLKIN
>
(1)
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