2. What is an ASM Chart?
● It is a special type of flow chart that is used to describe the
sequential operations of a digital circuit.
● The ASM chart determines the sequence of events, timing
relationship between the states of sequential controller ,and the
events that happen while going from one state to another
4. States
● State Name: The name of the state is indicated inside the circle
and the circle is placed in the top left corner or the name is placed
without the circle.
● State Box: The output of the state is indicated inside the rectangle
box.
● Decision box used in an ASM chart
5. STATE BOX
Each state box represents one state of the sequential circuit. The
symbol of state box is shown in the following figure. It is having one
entry point and one exit point. Name of the state is placed to the left of
state box.
6. Actions
● An ASM chart consists of an interconnection of four types of basic
elements:
state name, state box, decision box, and conditional outputs box.
● An ASM state, represented as a rectangle, corresponds to one state of a
regular state diagram or finite state machine. The More type outputs are
listed inside the box.
7. Transitions
● ASM charts represent real hardware. Therefore, all transitions
within ASM charts must form closed paths (except a reset signal).
● The state represented by the state box takes a clock cycle to
complete.
● The output signals in the box take the specified values during this
clock cycle.
9. Benefits and Applications
● It is a special type of flow chart that is used to describe the
sequential operations of a digital circuit.
● The ASM chart determines the sequence of events, timing
relationship between the states of sequential controller ,and the
events that happen while going from one state to another.
