$5\mathrm{.}11$ HOMEWORK PROBLEMS

$5\mathrm{.}1$ Work with a DVD player and develop an exhaustive set of events that you think the software

must sense and respond to$.$

$5\mathrm{.}2$ Identify the events and draw an STD for the behavior of a DVD player. Limit yourself to the

events generated by the DVD player $($ignore the remote control$).$

$5\mathrm{.}3$ Given a function GetRoomTemperature$()$ that returns the room temperature and a variable,

SetPoint, write a pair of functions in pseudo$-$code called IsTemperatureTooHot$()$ and IsTemper$-$

atureTooCool$()$ that return TRUE$-$FALSE values and together implement a hysteresis band

around the SetPoint temperature.

$5\mathrm{.}4$ Work with an answering machine to develop the list of events that the machine's software must

respond to$.$

$5\mathrm{.}5$ You are writing code to implement cruise control for a car. Given a function GetVehicleSpeed$()$

that returns the speed of a vehicle, write a single function TestAccelDecel$()$ in pseudo$-$code that

returns, NeedAccelerate, NeedDecelerate, or SpeedOK based on the speed relative to a set

point DesiredSpeed. To provide noise immunity, implement hysteresis around the switch point.

$5\mathrm{.}6$ In an application, the state of a switch is determined by reading a variable called PortA. The state

of the switch is indicated by the state value of bit $4$ within the byte variable PortA. In pseudo$-$

code, write an event checking function TestSwitch$()$ that returns Opened, Closed, or NoChange

depending on what has happened since the last time TestSwitch$()$ was called.

$5\mathrm{.}7$ Work with a microwave oven to develop the list of events that the oven's software must respond to$.$