RTOS Slides
23
1 J.O. KLEIN [email protected] Institut Universitaire de Technologie de CACHAN Université PARIS SUD - FRANCE An Introduction to Real Time Operating System with UCOS-II www.micrium.com Jean Labrosse Portable Royalty Free Readable Source Simple Well Suited for MCU Well documented
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Transcript of RTOS Slides
1J.O. KLEIN [email protected]
Institut Universitaire de Technologie de CACHANUniversité PARIS SUD - FRANCE
An Introduction to Real Time Operating System
with UCOS-II
www.micrium.com
Jean Labrosse
Portable
Royalty Free
Readable Source
Simple
Well Suited for MCU
Well documented
2
Background / InterruptModel Limitation
INT
Background
Loop …
TimeBCKGND
INT 1
ISR
ISR
ISRINT
INT
INT 0
ISR < 100 us
ISR > 1 ms Latency
ISR 0
INT 1-Pending
3
RTOS-Solution
ISR1
TimeIDLE
INT 1
INT 0
Task 1
ISR0
ISR1
Task 1
Task 1
ISR0
4
Practical Timing Ranges
RTOS Tick = Time unit for delay & timeout
1 us 1 ms 1 s
ISR
RT-Tasks
ProcessingTime
BackGnd-Tasks
T
5
UC/OS-II RTOS ObjectsSystem
ISR
INT
INTISR
INT
Task 0
T60
Ticks
ISR
T 10
Semaphore
T63IDLE
MessageQueue
Tx-FIFO
Mailbox
Timer INT
T61
T30
MemoryBuffers
6
Simple Tasksvoid myTask (void*pdata){
while (TRUE){…
OSTimeDly(ticks);}
}
TaskTicks
Task
Task
void myTask (void*pdata){while (TRUE){
…OS???Pend(ticks);}
}
??? := Sem | Mbox | Q
7
Polling & scheduling
while ((PTH & 8)==0){}
Task
Task
PORTH [3]
while ((PTH & 8)==0){OSTimeDly(1);
}
No context switching :Lower tasks are waiting
Context switching :Lower tasks can run
8
Interrupt Service Routine
interrupt VECTOR_NUMvoid myISR (void){
OSIntEnter();……OSIntExit();
}
OSIntNesting++
ISR
if (OSIntNesting-- == 0){…OSIntCtxSw();
}
Task 10
Task 5
ISRINT
Preemption
9
RT Ticks & Timer Interrupt
ISR
RT Timer
1 ms
OSTimeTick
Ticks
OSTimeDly(tick)
OS???Pend( event, tick, &err)
10
Semaphore
ISR Task
Task
Initial Value = 1
Initial Value = 0
if(mySem=OSSemCreate(InitialVal) != NULL)…
err=OSSemPost(mySem)
OS_EVENT*mySem
OSSemPend(mySem,tick, &err)
OptionalTimeout
tick:
11
Mail Box
Task
if (myMbox=OSMboxCreate(NULL)) != NULL)…
OptionalTimeout
err=OSMboxPost( myMbox,TxMessage)
RxMessage = OSMboxPend(myMBox,tick,&err)
OS_EVENT*myMbox
void*TxMessage
tick:
void*RxMessage
12
Message Queue
Task
If (myQ = OSQCreate(Buffer,N)) != NULL)…
…OSQPost(myQ,TxMsg)
RxMsg=OSQPend(myQ, ticks,&err)
OS_EVENT*myQ
…OSQPostFront(myQ,TxMsg)
…OSQFlush(myQ)
void*TxMsg
void*Buffer[N]
OptionalTimeout
tick:
void*RxMsg
err =…
13
Memory Buffer
If (myMem=OSMemCreate(buf,N,blksize,&err) != NULL)…
OSMemPut(myMem,&err)
OS_MEM*myMem
Buffer
TaskNO
TimeoutNo
wait
Buffer
OSMemGet(myMem,&err)
INT8U buf[N*blksize]
14
Code Architecture
XXX.C
XXX.H
XXX_EVENTS_INIT
MYTASK_CREATE
MYTASK
MAIN.C ALL_INCLUDES.H
Task
MAIN
INIT
StartRTOS.CSTAR12_Init
APP_Task_CREATE
RTOS_Checking
ALL_Events_Init
(HardwareConfiguration)
15
Creating a Task
err = OSTaskCreateExt (myTask, pdata, ptos, prio, id, pbos, MYTASK_stk_size, pext, opt);
Task
void myTask (void*pdata);static OS_STK MYTASK_stack[MYTASK_stk_size];void * ptos =
(void*)&MYTASK_stack[MYTASK_stk_size-1];void * pbos = (void*)&MYTASK_stack[0];INT8U prio = … ; // 0(higher) to 63(idle)INT8U id = 0; // unusedINT16U opt = OS_TASK_OPT_STK_CHK |
OS_TASK_OPT_STK_CLR; void*pdata = NULL; //optional data ptr void*pext = NULL; // optional ptr
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XXX.H
Code Generator
XXX.C
XXX_EVENTS_INIT
MYTASK_CREATE
MYTASK
17
Training Course
Introduction to RTOS Multitasking,
Scheduling Task States Preemptive/
Cooperative Task Stacks
Introduction to uCOSII Task, Semaphore,
Mbox,Q,Mem Starting the OS Code Architecture Code Generator
Getting Start Load the demo Add a commented task Debug !
Writing an Application Use Code Generator Adding the Files to
project Adding the task to the
App. Debug
1H30
Lecture Labs
1H00
2H00
3H00
ISR Task 0
18
Starsky
1 LineControl
2 MotorControl
3 LineSensor (I2C)
4 USSensor
5 Monitor (RS232)
6 Function
Application Tasks
60 RS232
61 LCD
62 Init (+RTOS Checking)
63 Idle
Service & System Tasks
19
Monitoring5 Monitor
60 RS232
62 Init (+RTOS Checking) CPU Usage
Stack Usage Delay 1s
Wait for RS232 Q
Constitute Frames
Copy msg to TxFIFO
Enable SCI Tx ISR
Send Sensors & Variables values through RS232
Print To LCD buffer
Delay 100 ms
61 LCD Copy LCD buffer
to LCD controller
Delay 100 ms
20
Application Starsky1 LineControl
2 MotorControl
Wait for MotorCtrlSem
Read Speed PI Controller or Open
loop Setting PWM Values
4 USSensor
Emit Ultrasound Delay 5ms Sample echo Delay 30 ms
3 LineSensor
Read line position /I2C
Delay 1 ms
Wait for LineCtrlSem ShortCut & Crossing
Detection End Detection Line Tracking
6 Function (Main Task)Select Mode (Stop,demo,normal…)Delay (variable)Set Motor Order or post LineCtrlSem
5 Monitor
Emit variable values via RS232 & LCD
Delay 100 ms
/
21
HC12 Enhanced Capture Timer
Free running Timer
Timer Capture Register
Timer CaptureHolding Register
Pulse Accumulator
Pulse AccumulatorHolding Register
PA Overflow
Read ICHReg
16
8
Frequency = Periodic PA sampling
Period =
TC - TCH
22
Frequency = Periodic PA sampling
Period =
TC - TCH
The choice
Frequency Measurement
UINT16 ECT_MOTOR_PT1_speed ( void ){ UINT16 Speed, Delta; Delta = (TC1 - TC1H); TotalPa1 += PA1H ; Speed_mm_per_sec = DiffPA1 * 21; return ( (Speed> 100) ?
(3272490UL / Delta) : Speed);}
Modulus Down Counter
5 ms
MotorCtrlSem
MotorControl
ISR
1/10
50 msvoid ECT_MOTOR_update(void) { Delta_ic1 = (TC1 - TC1H); // Tfer PA -> PAH Delta_ic3 = (TC3 - TC3H); // Tfer PA -> PAH TotalPa1 += PA1H; TotalPa3 += PA3H; DiffPA1 = TotalPa1 - TotalPa1_old; DiffPA3 = TotalPa3 - TotalPa3_old; TotalPa1_old = TotalPa1; TotalPa3_old = TotalPa3;}
23
Starsky Project• Professor
– STAR 12 Board design 3 months– STAR12 Software Lib 2 months– UCOS-II Port to STAR12 Board 1 month– UCOS-II/Star12 Service 1 month
• 20 Students group– Frequency, Motor controller,
H-bridge, RS232 Monitor, I2C 6 weeks– All together, Line tracking 6 weeks
• 3 students – Starsky & Hutch design 8 weeks
