DS-FND-BSX-PC Xilinx Inc, DS-FND-BSX-PC Datasheet - Page 180

• Manufacturer Part Number: DS-FND-BSX-PC
• Description: FOUNDATION BASE SYS W/SYN EXPRES
• Manufacturer: Xilinx Inc
• Type: Foundation Systemr

Specifications of DS-FND-BSX-PC

• For Use With/related Products: Xilinx Programmable Logic Devices
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: 122-1185

Foundation Series 2.1i User Guide
State Machine Example
State Diagram
7-2
“HDL Designs with State Machines” section of the “Design
Methodologies - HDL Flow” chapter.
The state machine in this example has four modes, which can be
selected by two inputs: DIR (direction) and SEQ (sequence). DIR
reverses the sequence direction; SEQ alters the sequence by swapping
the position of two of the numbers in the sequence. When the
machine is turned on, it starts in the initial state and displays the
number 9. It then sequences to the next number shown, depending
on the input. This sequence is summarized in the following table.
Table 7-1 State Relationships
Conceptual descriptions show the state progression and controlling
modes, but they do not clearly show how change conditions result.
The state diagram is a pictorial description of state relationships. The
“State Diagram” figure gives an example. Even though a state
diagram provides no extra information, it is generally easier to
translate this type of diagram into a state table. Each circle contains
the name of the state, while arrows to and from the circles show the
transitions between states and the input conditions that cause state
transitions. These conditions are written next to each arrow.
SEQ
1
1
0
0
DIR
1
0
1
0
Sequence of Displayed Number
9
9
9
9
5
4
5
1
2
2
1
2
1
1
2
4
5
4
5
9 . . .
9 . . .
9 . . .
9 . . .
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