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/*=============== U C O S D e m o . c ===============*/ /* BY: George Cheney Chene 16.472 / 16.572 Embedded Real Time Systems System Electrical and Computer Engineering Dept. Dept UMASS Lowell Lowel
*/ /* PURPOSE PURPOS Demonstrate Producer/Consumer task relationship. relationship DEMONSTRATES DEMONSTRATE Multitasking Multitaskin Semaphores Semaphore Circular Buffer Buffe CHANGES CHANGE 04-07-2003 gpc - Release to 16.472 / 16.572 class. class 04-07-2003 gpc - Add assert to timeout pends. pends 03-22-2006 gpc - Update for S2006. S2006 */ #include <stdlib.h> > #include #include #include #include #include #include #include #include "includes.h" "860types.h" "buffdesc.h" "mpc860.h" "860Init.h" "860SMC.h" "masks860.h" "assert.h" d e f i n i t i o n s -----*/ /* -- Timeout for semaphore wait */
/*----- c o n s t a n t #define SuspendTimeout 100 /* Task priorities prioritie */ enum t_prio { InitPrio ProducerPrio ConsumerPrio };
= 10, /* -- Initialization task */ , = 12, /* -- Producer task */ , = 11 /* -- Consumer task */
/* Circular buffer size */ #define BfrSize 512 /* Size of the stacks for each task */ #define TASK_STK_SIZE 2048 /*----- t y p e d e f i n i t i o n s -----*/
typedef struct { volatile INT16U in; in; volatile INT16U out; out; char bfr[BfrSize]; bfr ]; } CircBfr;
/* -- Input index */ /* -- output index */ /* -- Buffer space */
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/*----- g l o b a l
v a r i a b l e s -----*/
/* Circular buffer to pass data from Producer to Consumer */ CircBfr cBfr cBfr; /* Stack space for the three tasks */ OS_STK InitStk InitStk[TASK_STK_SIZE]; OS_STK ProducerStk ProducerStk[TASK_STK_SIZE]; OS_STK ConsumerStk ConsumerStk[TASK_STK_SIZE]; /* Semaphores */ OS_EVENT *bytesAvail; *bytesAvail; OS_EVENT *spacesAvail; *spacesAvail; OS_EVENT *txDone; /*----- f u n c t i o n void void void void void /* Consumer waits until bytes available in buffer. */ /* Producer waits until empty space available in buffer. /* Binary semaphore: Consumer waits until transmit done * p r o t o t y p e s -----*/
Init (void * data); Producer (void *data); Consumer (void *data); OutByte(int c); ExtInterrupt(void);
/*--------------- m a i n ( ) ---------------*/ int main (void) { INT32S idx; /* -- Index to task stacks */ idx; INT8U osErr;/* -- O/S Error Code */ osErr; /* Fill stacks with known values; good for seeing how much stack spac space is used. used */ for (idx = 0; idx < TASK_STK_SIZE; idx++) + { InitStk[idx] InitStk ] = 0xE0E1E2E3; ProducerStk[idx] = 0xE0E1E2E3; ProducerStk ] ConsumerStk[idx] = 0xE0E1E2E3; ConsumerStk ] } /* Initialize the UCOS-II Kernel. */ OSInit (); /* Create the Task Control Block (TCB) for the startup task. */ osErr = OSTaskCreate ( Init Init, NULL, NULL (void *)&InitStk[TASK_STK_SIZE], *)& InitPrio); InitPrio assert(osErr==OS_NO_ERR); assert = ); /* Start multi-tasking. */ OSStart(); OSStart /* No, it never returns... */ return 0; ; } /* This line will never execute. */
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/*--------------- I n i t ( ) ---------------*/ /* PURPOSE PURPOS Perform O/S and application initialization. initialization INPUT PARAMETERS PARAMETER data -- pointer to task data (not used* used GLOBALS GLOBAL bytesAvail -- Consumer waits on this. notFull -- Producer waits. waits txDone -- Consumer waits. waits cBfr -- the circular buffer. buffer */ void Init (void * data) { INT8U osErr; osErr; /* O/S Error Code */ /* Start the O/S clock tick. */ ticker_start (); /* Initialize the circular buffer. */ cBfr.in = 0; cBfr cBfr.out = 0; cBfr /* Create and initialize semaphores. */ bytesAvail = OSSemCreate(0); ); /* -- Empty at start. */ assert(bytesAvail!=NULL); assert ! spacesAvail = OSSemCreate(BfrSize); /* -- BfrSize bytes available. */ ); assert(spacesAvail!=NULL); assert ! txDone = OSSemCreate(1); ); assert(txDone!=NULL); assert ! /* -- No xmit yet; indicate ready. */
/* Initialize the O/S statistics task. */ #if OS_TASK_STAT_EN OSStatInit (); #endif /* Create Producer and Consumer tasks. */ osErr = OSTaskCreate ( Producer Producer, NULL, NULL (void *)&ProducerStk[TASK_STK_SIZE], *)& ProducerPrio); ProducerPrio assert(osErr==OS_NO_ERR); assert = ); osErr = OSTaskCreate ( Consumer Consumer, NULL, NULL (void *)& *)&ConsumerStk[TASK_STK_SIZE], ConsumerPrio); ConsumerPrio assert(osErr==OS_NO_ERR); assert = ); /* This task is done, so it deletes itself. */ osErr = OSTaskDel(InitPrio); assert(osErr==OS_NO_ERR); assert = ); }
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/*--------------- P r o d u c e r ( ) ---------------*/ /* PURPOSE PURPOS Generate alphabets and write them to the circular buffer buffer. INPUT PARAMETERS PARAMETER data -- Pointer to task data (not used ) GLOBALS GLOBAL bytesAvail -- Consumer waits on this. spacesAvail -- Producer waits. waits cBfr -- the circular buffer. buffer */ void Producer (void *data) { char c; /* -- Current character. */ INT8U osErr; osErr; /* -- Semaphore error code */ char cNext= cNext='A'; ; /* -- Next character */ /* Task runs forever, or until preempted or suspended. */ for(;;) for { /* Get next character to write. */ c = cNext; /* Advance next character. */ switch (cNext) { /* Send linefeed after carriage return. */ case '\r': cNext = '\n'; break; break /* Start alphabet over after linefeed. */ case '\n': cNext = 'A'; break; break /* Send carriage return after 'Z'. */ case 'Z': cNext = '\r'; break; break /* Otherwise, advance to next character in the alphabet. */ default: default ++cNext; break; break } /* Wait for buffer space */ OSSemPend(spacesAvail, SuspendTimeout, &osErr); OSSemPend , assert(osErr==OS_NO_ERR); assert = /* Write character to the buffer. */ cBfr.bfr[cBfr.in] = c; cBfr ] cBfr.in = (cBfr.in + 1) % BfrSize; cBfr ) /* Signal the Consumer that the buffer is not empty. */ osErr = OSSemPost(bytesAvail); assert(osErr==OS_NO_ERR); assert = } }
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/*--------------- C o n s u m e r ( ) ---------------*/ /* PURPOSE PURPOS Read characters from the circular buffer and output to the SMC SMC1 transmitter. transmitter INPUT PARAMETERS PARAMETER data -- task data pointer (not used) used GLOBALS GLOBAL bytesAvail -- Consumer waits on this. spacesAvail -- Producer waits. waits txDone -- Consumer waits. waits cBfr -- the circular buffer. buffer */ void Consumer (void *data) { char c; /* -- The next character to output */ INT8U osErr; osErr; /* -- Semaphore error code */ /* Task runs forever, or until preempted or suspended. */ for(;;) for { /* Wait for buffer not empty. */ OSSemPend(bytesAvail, SuspendTimeout, &osErr); OSSemPend , assert(osErr==OS_NO_ERR); assert = /* Get the next character from the buffer. */ c = cBfr.bfr[cBfr.out]; cBfr.out = (cBfr.out + 1) % BfrSize; cBfr ) /* Output character to tx. */ OutByte(c); OutByte /* Signal the Producer tha...