Hands-On: Mode Manager in Stateflow

// HVAC Mode Manager -- Stateflow chart, Ts=100ms
// State: OFF
// entry: compressor_on=false; heater_on=false;
//        blower_speed=0; hvac_mode=0;
// OFF -> STARTUP: [ignition]

// State: STARTUP
// entry: blower_speed=100; hvac_mode=1;
// STARTUP -> COOLING: [after(0.2,sec) && cabin_temp_C >= setpoint_C+1.0]
// STARTUP -> HEATING: [after(0.2,sec) && cabin_temp_C <= setpoint_C-1.0]
// STARTUP -> COOLING: [after(0.2,sec)]  // default: cooling

// State: COOLING
// entry: compressor_on=true; heater_on=false;
//        blower_speed=200; hvac_mode=2;
// COOLING -> HEATING: [cabin_temp_C < setpoint_C - 2.0]
// COOLING -> OFF:     [~ignition]
// COOLING -> FAULT:   [~compressor_ok && after(0.5,sec)]

// State: HEATING
// entry: compressor_on=false; heater_on=true;
//        blower_speed=180; hvac_mode=3;
// HEATING -> COOLING: [cabin_temp_C > setpoint_C + 2.0]
// HEATING -> OFF:     [~ignition]

// State: FAULT
// entry: compressor_on=false; heater_on=false;
//        blower_speed=50; hvac_mode=99;
// FAULT -> OFF: [~ignition]  // operator must cycle ignition to reset

% Test case 1: Normal startup -> COOLING
setparam("HVAC_Test","ignition",1,"cabin_temp_C",28,"setpoint_C",22);
setparam("HVAC_Test","compressor_ok",1,"blower_ok",1);
out1 = sim("HVAC_Test", 3.0);
assert(out1.hvac_mode.Data(end)==2, "Expected COOLING");

% Test case 2: COOLING -> HEATING (cabin cooled)
setparam("HVAC_Test","cabin_temp_C",18);
out2 = sim("HVAC_Test", 3.0);
assert(out2.hvac_mode.Data(end)==3, "Expected HEATING");

% Test case 3: Fault injection (compressor failure)
setparam("HVAC_Test","cabin_temp_C",28,"compressor_ok",0);
out3 = sim("HVAC_Test", 3.0);
% After 0.5s debounce -> FAULT; blower_speed=50
assert(out3.hvac_mode.Data(end)==99, "Expected FAULT");
assert(out3.blower_speed.Data(end)==50, "Expected safety blower");

% Test case 4: Glitch (fault clears before debounce)
% compressor_ok=0 for 0.3s only -> stays in COOLING

% Test case 5: Shutdown
setparam("HVAC_Test","ignition",0,"compressor_ok",1);
out5 = sim("HVAC_Test", 1.0);
assert(out5.hvac_mode.Data(end)==0, "Expected OFF");