📄 chap.8.interrupts.ps
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3832(very)X4037(costly.)X576 915(This)N771(is)X859(why)X1048(the)X1190(interrupt-driven)X1824(scheme)X2137(of)X2241(Figure)X2516(8.1b)X2708(may)X2898(be)X3013(considered)X3454(to)X3553(be)X3668(more)X3 f3890(ef\256cient)X1 f4216(.)X776 1055(A)N869(second)X1160(problem)X1505(with)X1700(a)X1767(polled)X2033(scheme)X2347(as)X2452(in)X2552(Figure)X2828(8.1a)X3016(is)X3105(illustrated)X3516(as)X3621(follows.)X3982(Assume)X576 1167(we)N724(have)X942(a)X1021 0.2898(time-related)AX1524(function)X1881(occurring)X2286(in)X2397(a)X2476(device)X2764(and)X2939(it)X3029(is)X3129(critical)X3433(that)X3613(the)X3766(CPU)X3987(respond)X576 1279(very)N771(quickly)X1084(after)X1285(some)X1512(external)X1847(event)X2080(has)X2232(occurred.)X2641(If,)X2753(in)X2852(the)X2994(polled)X3260(system,)X3576(the)X3719(minimum)X4119(time)X576 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5687(ous)N739(section.)X1066(Assume)X1405(that)X1580(the)X1728(main)X1951(function)X2303(of)X2414(the)X2563(control)X2867(program)X3224(is)X3319(to)X3425(periodically)X3917(check)X4173(the)X576 5799(input)N803(sensors)X1114(\(aircraft)X1454(attitude,)X1797(elevation,)X2204(airspeed,)X2578(etc\))X2752(and)X2920(in)X3024(response)X3389(to)X3492(perform)X3830(calculations)X61 p%%Page: 61 412 s 0 xH 0 xS 1 f3 f576 400(57:017)N872(CIE)X1 f2329(-)X2385(61)X2505(-)X3 f3717(Lecture)X4062(Notes)X1 f576 803(to)N675(adjust)X929(its)X1044(outputs)X1351(\(engine)X1664(thrust,)X1931(\257aps,)X2160(etc\).)X2353(This)X2548(might)X2797(be)X2912(done)X3123(as)X3227(in)X3326(Figure)X3601(8.2.)X7 f1152 963(main\(\))N1558({)X1152 1187(while)N1500(\(1\))X1732({)X1728 1299(/*)N1902(Normal)X2308(Sample)X2714(and)X2946(Control)X3410(*/)X1728 1411(x)N1844(=)X1960 0.3906(sample_attitude_sensor\(\);)AX1728 1523 0.4062(set_flaps\(x\);)AN1728 1635(y)N1844(=)X1960 0.3906(check_desired_altitude\(\);)AX1728 1747 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