function servo_init(mode)% PID-control of a DC servo process.%% This example shows four ways to implement a periodic controller% activity in TrueTime. The task implements a standard% PID-controller to control a DC-servo process (2nd order system). % Initialize TrueTime kernelttInitKernel(2, 1, 'prioFP'); % nbrOfInputs, nbrOfOutputs, fixed priority% Task attributesperiod = 0.006;deadline = period;offset = 0.0; % start of first task jobprio = 1;% Create task data (local memory)data.K = 0.96;data.Ti = 0.12;data.Td = 0.049;data.beta = 0.5;data.N = 10;data.h = period;data.u = 0;data.Iold = 0;data.Dold = 0;data.yold = 0;data.rChan = 1;data.yChan = 2;data.uChan = 1;switch mode, case 1, % IMPLEMENTATION 1: using the built-in support for periodic tasks ttCreatePeriodicTask('pid_task', offset, period, prio, 'pidcode1', data); case 2, % IMPLEMENTATION 2: calling Simulink block within code function data2.u = 0; % Only the control signal needs to be stored between               % segments. Controller states are stored internally by               % TrueTime. ttCreatePeriodicTask('pid_task', offset, period, prio, 'pidcode2', data2); case 3, % IMPLEMENTATION 3: sleepUntil and loop back data.t = 0; ttCreateTask('pid_task', deadline, prio, 'pidcode3', data); ttCreateJob('pid_task'); case 4, % IMPLEMENTATION 4: sampling in timer handler, triggers task job hdl_data.yChan = 2; ttCreateInterruptHandler('timer_handler', prio, 'samplercode', hdl_data); ttCreatePeriodicTimer('timer', offset, period, 'timer_handler'); ttCreateMailbox('Samples', 10); ttCreateTask('pid_task', deadline, prio, 'pidcode4', data);end