Interrupt-Driven Digital Control

Transcription

1 Interrupt-Driven Digital Control

2 Digital Control System Digital Computer Command + Controller D/A Control Signal Plant A/D T Sampler Sensor

3 Interrupt Main Program Interrupt Service Routine

4 PC Interrupt

5 PC Interrupt

6 PC Interrupt

7 PC bus AD board IRQ5 AD Converter Timer AD conversion start AD conversion end Timer AD Converter IRQ Interrupt Request T (Sampling Period)

8 Interrupt Definitions Hardware signal indicating an event has happened and needs to be serviced Latency The time from when the interrupt occurred to when the event is serviced

9 Threads and Processes Thread A unit of execution A piece of code that can be scheduled to run by the kernel May be launch by a process or a driver Process A collection of threads with a common execution environment A process has at least on thread Launch from an executable file Can create threads to handle interrupts

10 ISRs and ISTs Interrupt Service Routine (ISR) A piece of code loaded into the kernel Assigned to a particular IRQ Called immediately to handle the hardware interrupt Should be written to run quickly with few outside dependencies Can be chained together if multiple device might use the same IRQ Notifies the kernel which IST should run Interrupt Service Thread (IST) A thread registered to handle an interrupt Can be created by either a process or a driver Scheduled like any other thread on the system Should be written to do the bulk of the interrupt handling work

11 ISRs and ISTs Work Together ISRs and ISTs usually work as pairs ISR handles the critical work IST handles the bulk of the work They synchronize by using an Event Object The IST creates an Event Object Uses the API WaitForSingleObject to sit and wait on that object to be signaled The ISR tells the kernel which object to signal Which unblocks the IST and makes it runable If the IST is the highest priority runable thread, it will get scheduled to run immediately

12 Priority Levels Windows CE 5.0 has 256 levels of priority Level 0 is the highest and 255 is the lowest The old CE model of 8 levels now map to the lowest 8 of the new model The default level for a thread is 251

13 Scheduler Is responsible for determining which thread will run Has a queue for threads for each priority level Will always schedule the first thread at the highest priority level A thread gets to run for set length of time, called a quantum Typically 100 milliseconds A quantum of 0 means the quantum never runs out The thread can run until blocked or interrupted A Thread runs until Its quantum runs out It is interrupted by a higher priority thread Its blocked by a resource contention Such as access to a critical section or a mutex

14 Fitting It All Together Interrupt Occurs Interrupt Handler calls registered ISR ISR runs, tells kernel which event to signal IST runs and resets the interrupt Scheduler runs the IST Kernel signals event, IST becomes runnable

15 Interrupt Architecture

16 Program Template(1) #define AD_BASE #define AD_LOW_BYTE #define AD_HIGH_BYTE #define AD_MUX #define AD_STATUS #define AD_CONTROL #define COUNTER0 #define COUNTER1 #define COUNTER2 #define COUNTER_CONTROL #define DA_BASE #define DA_CHANNEL1_HIGH #define DA_CHANNEL1_LOW #define DA_CHANNEL2_HIGH #define DA_CHANNEL2_LOW 0x300 AD_BASE AD_BASE+1 AD_BASE+2 AD_BASE+8 AD_BASE+9 AD_BASE+12 AD_BASE+13 AD_BASE+14 AD_BASE+15 0x2c0 DA_BASE DA_BASE+1 DA_BASE+2 DA_BASE+3 #define ONMASK 0xdf /* Turn IRQ5 On */ #define OFFMASK 0x20 /* Turn IRQ5 Off */ #define PICMASK 0x21 /* 8259 Mask Register */ #define PICEOI 0x20 /* 8259 EOI Instruction */ #define DEBUGMODE 1

17 Program Template(2) int WINAPI WinMain( { DWORD IDThread; HINSTANCE hinstance, HINSTANCE hprevinstance, LPTSTR lpcmdline, int ncmdshow) hintrthread=createthread(0,0,intrthread,0,0,&idthread); if (hintrthread==null) { printf("[error]:failed to create IntrThread\r\n"); return 0; } if (!CeSetThreadPriority(hIntrThread,200)) { printf("cesetthreadpriority - Fail\n"); } } MessageBox(NULL, TEXT("Press OK to finish"),text("notice"),mb_ok); return 0;

18 Program Template(3) DWORD IntrThread(PVOID parg) { int high_byte,low_byte; long y,x; hintrevent=createevent(null, FALSE, FALSE, NULL); if (!(InterruptInitialize(SYSINTR_FIRMWARE+5,hIntrEvent,0,0))) { printf("interrupt Thread Initialize - Fail\r\n"); } else { printf("interrupt Thread Initialize - Success\r\n"); } _outp(ad_mux,0); /* AD channel selection */ _outp(ad_base+1,0); /* AD range control */ _outp(ad_control,0xd3); /* set AD mode */ InitializeTimerInterrupt(); _outp(ad_status,0); /* clears AD interrupt */

19 Program Template(4) interruptcounter=0; while(1) { WaitForSingleObject(hIntrEvent, INFINITE); interruptcounter++; low_byte=_inp(ad_low_byte) & 0xFF; high_byte=_inp(ad_high_byte) & 0xFF; x= (low_byte>>4)+(high_byte<<4)-2048; y=x; y=y+2048; low_byte= y & 0xff; high_byte= (y >> 8) & 0x0f; _outp(da_channel1_high,high_byte); _outp(da_channel1_low,low_byte); _outp(da_channel1_high,high_byte); _outp(ad_status,0); /* clears AD interrupt */ } } InterruptDone(SYSINTR_FIRMWARE+5);

20 Program Template(5) void InitializeTimerInterrupt(void) { unsigned short count; /* Initilize the timer */ count=10; _outp(counter_control,0x74); /* */ _outp(counter1,(count & 0xff)); _outp(counter1,((count >> 8) & 0xff)); count=20; _outp(counter_control,0xb4); /* */ _outp(counter2,(count & 0xff)); _outp(counter2,((count >> 8) & 0xff)); /* count=10,count=50 : 2KHz for 1MHz clock input */ /* count=10,count=20 : 5KHz for 1MHz clock input */ } /* InitializeTimerInterrupt */

21 PCL-818L

22 Two s complement 입력전압 입력값 Two s complement (long integer: 4 bytes) 10*(2047/2048) 0xfff 0x000007ff 10*(1/2048) 0x801 0x x *(1/2048) 0x7ff 0xffffffff -10 0x0 0xfffff800

23 AD connection

24 DA Connection 5 번그라운드 1 번출력

25 실험 1: AD & DA

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27 실험 2: 구형파발생 주파수가 100Hz, 10Hz, 1Hz 인구형파 (0 volt- 1volt) 를발생시켜서 DA converter 로출력한다. 주어진 sample program 은 5KHz 의주기로인터럽트가발생되어, 인터럽트서비스루틴이동작된다. 따라서 global 변수로서 interrupt counter 변수를정의한후, 이변수를적절히사용하여위의주파수를갖는구형파를발생시켜오실로스코프로확인한다.

28 실험 3: AD 변환값저장 함수발생기로부터주파수가 10 Hz 인정현파를발생시켜서이를 AD converter 로입력한후, 0.1 초구간동안 (500 sample, 정현파 1 주기 ) 의입력값을저장한후, 이를 plotting 하여정현파의그래프가그려짐을확인한다. 이때 AD converter 로입력된데이터를저장하기위해서는저장하려는데이터의갯수만큼 global 변수 array 로서정의한후, Interrupt Service Thread 내에서 AD converter 입력값을변수에저장하고, 이변수 array 가모두채워지면, 파일에저장하도록한다. Interrupt Service Thread 내에서는파일저장을수행해서는안된다.

29 실험 3: AD 변환값저장 File save 를위한별도의 Thread 생성 File save thread 는 IST 보다낮은 priority 가짐 IST 에서는실시간으로변수에값을저장하고, 변수의저장이완료되면 flag 를 set 함. File save thread 에서는변수의저장이완료됨을알리는 flag 가 set 되는것을기다림. 변수의저장이완료되면 file 에 save 하고 file 을 close 함.

30 Digitization

31 Digitization

32 Digitization ZOH(zero order hold)

33 Laplace Transforms Laplace Transform st L[ f()] t = F() s = f() t e dt L[ f ( t)] = sf( s) yt () + ayt () + byt () = ut () 0 () + () + () = () 2 s Y s asy s by s U s Gs () Y() s 1 = = () U s s as b

34 z-transform z-transform Z [ f( k)] = F( z) = f( k) z Z = k = 0 1 [ f( k 1)] z F( z) k

35 z-transform yk ( ) = ayk ( 1) ayk ( 2) + buk ( ) + buk ( 1) + buk ( 2) Y( z) = a z Y( z) a z Y( z) + bu( z) + bz U( z) + b z U( z) Y( z) b + bz + bz = U( z) 1 + az + az

36 z-transform example 1 k 0 ek ( ) = 0 k < z 1 Ez ( ) = 1 + z + z + = =, z < z z 1 a k k 0 ek ( ) = 0 k < z 1 E( z) = 1 + az + a z + = =, az < az z a

37 Inverse z-tranform z Ez ( ) = ( z 1)( z 2) Ez ( ) = = + z ( z 1)( z 2) z 1 z 2 z z Ez ( ) = + z 1 z 2 k ek ( ) = 1+ 2, k 0

38 System Response yk ( ) = ayk ( 1) + uk ( ) Y z = az Y z + U z 1 ( ) ( ) ( ) Y( z) 1 z Gz ( ) = = = ( ) 1 z U( z) = z 1 z z Y( z) = G( zu ) ( z) = z az 1 1 U z az z a

39 System Response Y( z) z a/( a 1) 1/(1 a) = = + z ( z a)( z 1) z a z 1 za /( a 1) z /(1 a) Y( z) = + z a z 1 1 a k yk ( ) = + a, k 0 1 a a 1

40 Relationship Between s and z at f() t = e, t 0 1 F() s = pole : s = a s+ a akt f ( kt ) = e, k 0 Z [ f( k)] 1 e z e z at 1 a2t 2 = z = = pole : z = at 1 at 1 e z z e e at z = e st

41 Relationship Between s and z s = jω jωt z = e = cos( ωt) + jsin( ωt) = 1 ( ωt) ωs 2π fs π ω = = = ωt = π 2 2 T

42 Relationship Between s and z

43 Relationship Between s and z

44 Relationship Between s and z

45 Continuous System

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