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XC4013E-3PQ160I Datasheet, PDF (16/68 Pages) Xilinx, Inc – XC4000E and XC4000X Series Field Programmable Gate Arrays | |||
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Product Obsolete or Under Obsolescence
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XC4000E and XC4000X Series Field Programmable Gate Arrays
G1
G4
F2
F1
F3
M
M
0
1
M
M
1
I
0
C OUT
0
1
M
G2
M
1
M
0
G3
C OUT0
0
1
M
F4
3
1
M
0
M
M
1
0
X2000
Figure 14: Detail of XC4000E Dedicated Carry Logic
C IN UP
C IN DOWN
TO
FUNCTION
GENERATORS
Input/Output Blocks (IOBs)
User-conï¬gurable input/output blocks (IOBs) provide the
interface between external package pins and the internal
logic. Each IOB controls one package pin and can be con-
ï¬gured for input, output, or bidirectional signals.
Figure 15 shows a simpliï¬ed block diagram of the
XC4000E IOB. A more complete diagram which includes
the boundary scan logic of the XC4000E IOB can be found
in Figure 40 on page 43, in the âBoundary Scanâ section.
The XC4000X IOB contains some special features not
included in the XC4000E IOB. These features are high-
lighted in a simpliï¬ed block diagram found in Figure 16, and
discussed throughout this section. When XC4000X special
features are discussed, they are clearly identiï¬ed in the
text. Any feature not so identiï¬ed is present in both
XC4000E and XC4000X devices.
IOB Input Signals
Two paths, labeled I1 and I2 in Figure 15 and Figure 16,
bring input signals into the array. Inputs also connect to an
input register that can be programmed as either an
edge-triggered ï¬ip-ï¬op or a level-sensitive latch.
The choice is made by placing the appropriate library sym-
bol. For example, IFD is the basic input ï¬ip-ï¬op (rising edge
triggered), and ILD is the basic input latch (transpar-
ent-High). Variations with inverted clocks are available, and
some combinations of latches and ï¬ip-ï¬ops can be imple-
mented in a single IOB, as described in the XACT Libraries
Guide.
The XC4000E inputs can be globally conï¬gured for either
TTL (1.2V) or 5.0 volt CMOS thresholds, using an option in
the bitstream generation software. There is a slight input
hysteresis of about 300mV. The XC4000E output levels are
also conï¬gurable; the two global adjustments of input
threshold and output level are independent.
Inputs on the XC4000XL are TTL compatible and 3.3V
CMOS compatible. Outputs on the XC4000XL are pulled to
the 3.3V positive supply.
The inputs of XC4000 Series 5-Volt devices can be driven
by the outputs of any 3.3-Volt device, if the 5-Volt inputs are
in TTL mode.
Supported sources for XC4000 Series device inputs are
shown in Table 8.
6-20
May 14, 1999 (Version 1.6)
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