A Turnkeyed Application

// Turnkeyed Application Code Listing, C Language version.
// This is a complete real-time application program, with instructions on
// how to set up the program to AUTOSTART each time the processor starts up.
 
// Copyright 2004 Mosaic Industries, Inc.  All Rights Reserved.
//  Disclaimer: THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT ANY
//  WARRANTIES OR REPRESENTATIONS EXPRESS OR IMPLIED, INCLUDING, BUT NOT
//  LIMITED TO, ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS
//  FOR A PARTICULAR PURPOSE.
 
// ************************ Turnkeying a QED Application ********************
//
// This is the code for an example application.  The accompanying chapter
// presents a detailed explanation of this code. The code can run on a QVGA
// Controller with the minimum memory configuration.
 
// Description of the application:
// This program reads an input voltage, creates a pulse width modulated (PWM)
// signal whose average value tracks the input voltage, and reports the
// mean and standard deviation of the input voltage.  The following 3 tasks do
// the work:
 
// Task 1: Reads 8 bit A/D input AN0, measuring the voltage on a potentiometer
//                connected to PortE pin PE0/AN0.
 
// Task 2: Outputs on Port A bit 5 a PWM signal whose average equals the A/D
//                input.
 
// Task 3: Every 1 second puts A/D value into a matrix, and every 10 seconds
//         displays the mean and standard deviation of the last 10 seconds
//         worth of data.
//
// The following issues are addressed:
//
//      Using the default C memory map as set up by the MAKE utility
//      Proper initialization of tasks at startup
//      Autostarting
//      Interrupt service routines and interrupt attaching
//      In-line assembly coding
//      Initialization of the heap memory manager
//      Timesliced multitasking
//      ColdOnReset() for secure restart
//      Floating point calculations
//      Using the display
//      Generation of a PROM image of application
//      Going into production
 
// ************************ Default Memory Map ************************
 
// 0-7FFF (32K) in page 4 is user application code
 
// 4600-7FFF (14.5K) in page 0F is RAM Heap area that holds banked array data.
 
// 3000-45FF (5.5K) in page 0F is a heap for the graphics display buffer.
 
// 8E00-ADFF is available common RAM (the C .data and .init sections)
//      which hold C variables, C arrays, and pfa’s (parameter field areas)
//      of FORTH_ARRAYs.
 
// B000-B3FF is 1K 68HC11 on-chip RAM; the top 48 bytes
//      at B3D0-B3FF are reserved.
 
// AEC0-AFFF is available EEPROM referenced by the .eeprom section
//      {EEPROM at AE00-AEBF is reserved for startup utilities
//       and interrupt revectoring}
 
// QED-Forth ROM occupies 0-7FFF on page 0, 0-2FFF on page F,
//      and B400-FFFF in common ROM.
 
 #include <\mosaic\allqed.h>     // include all of the qed and C utilities
 
// *********************** 8 BIT A/D Data Gathering Task *********************
 
// This task gathers data from the 8 bit A/D and places it in a variable
// easily accessed by other tasks.
 
// Define the control registers and some useful constants:
 
#define AD8_INPUT_CHANNEL       ((char) 0)
// You can use any channel you want and place the input potentiometer on
// the corresponding A/D8 input pin.  For example, if 0 is your input
// channel, place the input signal on the pin labeled AN0 (pin 10 of
// the analog connector).
 
static float input_voltage;
        // Holds voltage corresponding to latest result of A/D input. Because the
        // contents of this variable are shared among several tasks, we use
        // uninterruptable PokeFloatUninterrupted and PeekFloatUninterrupted
        // to access it.
 
// Now we convert a measured count from the A/D that ranges from 0 to 255
// into a voltage that ranges from 0.0 Volts (the low reference voltage)
// to nearly 5.0 Volts (the high reference voltage).
// This involves solving the equation:
// Voltage=[(high.ref.voltage -
              low.ref.voltage)*measured.count/256]+low.ref.voltage
 
// First let’s define some constants:
#define FULL_SCALE_COUNTS       256     // 256 counts in an 8 bit converter
#define LOW_VREF                0.0
#define HIGH_VREF               5.0
         // NOTE: For maximum accuracy, measure +5VAN with a voltmeter and
         //        set HIGH.REF.VOLTAGE equal to the result.
 
_Q float CountToVolts(int count)
        // This routine converts 8 bit A/D measured count n { 0 <= n <= 255 }
        // to the corresponding floating point voltage r
        // {typically, 0.0 <= r <= 5.0 }  by solving the equation:
        // r = [ (high.ref - low.ref) * count / 256 ]  + low.ref
{  return( ((HIGH_VREF - LOW_VREF) * count / FULL_SCALE_COUNTS) + LOW_VREF );
}
 
_Q  _protect  void PokeFloatUninterrupted(float value, float* destination )
// stores value into the address specified by destination;
// the _protect keyword guarantees that
// interrupts will be disabled while this function executes;
// this prevents corruption of data when two tasks are accessing the same
// 4-byte variables
{  *destination = value;
}
 _Q  _protect  float PeekFloatUninterrupted(float *  source )
// fetches and returns the contents from the address specified by source;
// the _protect keyword guarantees that
// interrupts will be disabled while this function executes;
// this prevents corruption of data when two tasks are accessing the same
// 4-byte variables
{  return *source;
}
 
_Q void GatherData(void)
// This is the activation routine for the data gathering task.
// It continually acquires readings from the A/D, converts the readings
// to voltages, and updates the input_voltage variable that is accessed
// by other tasks.
{       uchar sample;
        float sample_voltage;
        AD8On();                        // make sure A/D is powered up
        while(1)                        // start infinite loop
        {       sample = AD8Sample(AD8_INPUT_CHANNEL);
                sample_voltage = CountToVolts(sample);
                PokeFloatUninterrupted(sample_voltage, &input_voltage);
                Pause();
        }
}
 
// ********************* Pulse Width Modulation (PWM) Task ********************
 
// This task calculates the high time and low time of the PWM output based on
// the value of the input_voltage which is updated by the data gathering task.
// The goal is to set the duty cycle of the PWM output so that the average of
// the PWM signal equals the input_voltage. This is achieved by solving the
// equation:
//      DutyCycle = (input_voltage - low.output) / (high.output - low.output)
//      in which low.output and high.output are the voltage levels that appear
//      on the PWM output pin in the low and high states, respectively.
 
// Given the duty cycle, and given our choice of a PWM period of 130 msec, we
// calculate the high.time and low.time of the PWM signal in terms of the timer
// counts; each timer count equals 2 microseconds.  high_time is the number of
// timer counts that the signal is in the high state and low_time is the number
// of timer counts that the signal is in the low state during each 130 msec
// period.  high_time and low_time are calculated as:
//      high_time = Duty.cycle * TIMER_COUNTS_PER_PERIOD
//      low_time = TIMER_COUNTS_PER_PERIOD - high_time
//              where TIMER_COUNTS_PER_PERIOD = 130 msec/2 microsec = 65,000.
 
// We also //clamp// high_time and low_time to a minimum value to prevent a
// situation where interrupts are requested so rapidly that the processor
// can’t service them.
 
// The OC3 (output compare 3) interrupt code in the subsequent section uses
// these calculated values to pulse width modulate the PORTA output port pin
// PA5.
 // We define some variables and constants:
 
static uint high_time;   // the number of timer counts that PWM output is high
static uint low_time;    // the number of timer counts that PWM output is low
static float duty_cycle;
 
#define LOW_OUTPUT_VOLTAGE      0.0     // the voltage on PA5 when it is low
#define HIGH_OUTPUT_VOLTAGE     5.0     // the voltage on PA5 when it is high
// NOTE: for maximum accuracy, the voltage output of pin PA5 could be measured
//   in the low and high states and LOW_OUTPUT_VOLTAGE and HIGH_OUTPUT_VOLTAGE
//   set accordingly.
 
#define MS_PER_PERIOD   130    // use a 130 msec period for PWM output
                               // NOTE: the timer rolls over every 131 msec
 
#define TIMER_COUNTS_PER_PERIOD         65000
//   130 milliseconds corresponds to 65,000 counts of 2 microseconds (usec)
//   each on the free-running timer.  QED-Forth sets the contents of TMSK2 so
//   that each timer count represents 2 usec.  This is true whether the crystal
//   speed is 8 MHz or 16MHz.  We assume here that the programmer has not
//   installed a different value in TMSK2 using InstallRegisterInits().
 
#define MINIMUM_HIGH_OR_LOW_TIME  ((int) 250)    // corresponds to 500usec
// we choose a minimum high or low time approximately equal to the maximum
// number of timer counts divided by 256.  That is, we only require 8 bits of
// resolution from our PWM.  The benefit of imposing a minimum high or low time
// is that bey doing so we can ensure that the minimum time between PWM
// interrupts is 500 usec.  This is more than sufficient time to allow the
// service routine to execute.
 
_Q void CalculateDutyCycle(void)
// implements the equation:
//     duty_cycle = (input_voltage-low.output)/(high_output-low_output)
// duty_cycle is in the range 0.0 to 1.0
{   duty_cycle = (input_voltage - LOW_OUTPUT_VOLTAGE)
                               / (HIGH_OUTPUT_VOLTAGE - LOW_OUTPUT_VOLTAGE);
    duty_cycle = MIN((float) 1.0, duty_cycle) ;
    duty_cycle = MAX((float) 0.0, duty_cycle) ; // clamp to 0<=duty_cycle<=1.0
}
 
_Q void HighAndLowTimes(void)
// saves high and low times as 16bit integer counts in the variables
// high_time and low_time using the equations:
//     high_time = duty_cycle * TIMER_COUNTS_PER_PERIOD
//     low_time  = TIMER_COUNTS_PER_PERIOD - high_time
// both high_time and low_time are clamped to a minimum so that timer interrupts
// don’t occur more frequently than they can be reliably serviced.
{
  high_time = MAX((TIMER_COUNTS_PER_PERIOD *
                 duty_cycle),MINIMUM_HIGH_OR_LOW_TIME);
  low_time = MAX((TIMER_COUNTS_PER_PERIOD - high_time),MINIMUM_HIGH_OR_LOW_TIME);
  high_time = TIMER_COUNTS_PER_PERIOD - low_time;
  // make sure that high_time + low_time is exactly one period despite clamping
}
 
 _Q void SetPulseParameters( void )
        // this is the activation roution for the pwm task.  It updates the
        // values in high_time and low_time for use by the oc3 interrupt which
        // generates the pwm output waveform on PORTA pin PA5.
{       while(1)
        {       CalculateDutyCycle();
                HighAndLowTimes();
                Pause();
        }
}
 
// ********************* OC3 Interrupt Code **********************
// This interrupt routine generates a pulse width modulated output on Port A
// bit 5 based on the duty cycle calculated by the PWM task.
// There are 4 steps involved in coding an interrupt service routine:
//      1.  Name all required hardware registers (see the QEDREGS.H file in the
//              \MOSAIC\FABIUS\INCLUDE\MOSAIC directory),
//              and name all required bit masks with appropriate mnemonics.
//      2.  Use C or assembly code to define an interrupt handler which
//              must clear the interrupt request flag and perform required
//              service actions.
//      3.  Install the interrupt handler using the Attach() function.
//      4.  Write routines to enable and disable the interrupt.  (We combine
//          steps 3 and 4 in a routine that ATTACHes and enables the interrupt).
 
// Define output mode configuration flags and masks that specify action
// to be performed when a successful output compare occurs:
#define PA5_MASK                0x20  // mask for setting/resetting PA5
#define OC3_MASK                0x20  // to set/clr OC3 interrupt flag & mask
#define OC3_MODE_MASK           0x20  // mask in TCTL1; enables PA5 pin control
#define OC3_LEVEL_MASK          0x10  // mask in TCTL1; controls level of PA5
 
// Summary of the functions of these registers: OC3 (output compare 3) is
// associated with pin PA5 on PORTA.  We can write a 16 bit count into the TOC3
// register, and when the count in TOC3 matches the count in the main counter
// TCNT, an interrupt request can occur.  The request only occurs if interrupts
// are globally enabled and if the OC3 interrupt is locally enabled.  The OC3
// interrupt is locally enabled by setting the bit specified by the OC3_MASK in
// the TMSK1 register.  When the interrupt request occurs, the 68HC11
// automatically sets the bit specified by OC3_MASK in the TFLG1 (timer flag
// #1) register.  Our interrupt service routine must clear this bit (oddly
// enough, interrupt request bits are cleared by writing a 1 to the bit
// position!) The register TCTL1 controls whether the state of the PA5 bit is
// automatically changed when TOC3 matches TCNT.  In this application we enable
// this automatic //pin control// action by setting the bit specified by
// OC3_MODE_MASK in TCTL1.  The bit specified by OC3_LEVEL_MASK in TCTL1 then
// controls the level (high or low) to which PA5 is set upon a successful
// output compare.
 
 _Q void OC3Service(void)
{       char temp = OC3_LEVEL_MASK;
        TFLG1 = OC3_MASK;  // reset the oc3 interrupt flag so that new oc3
                           // interrupts will be recognized. because the flag
                           // is cleared by writing a one to it we can use a
                           // assignment command without affecting other bits.
        if( temp &= TCTL1 )   // look at the oc3/pa5 pin output level
        {       TCTL1 &= ~OC3_LEVEL_MASK;      // AND with complement of mask
                TOC3 += high_time;
        }                  // if the output level just toggled high we’ll
                           // set the mode/level bit so the next output
                           // compare forces the pin low after the high_time
        else               // else if the output level just toggled low...
        {       TCTL1 |= OC3_LEVEL_MASK;
                TOC3 += low_time;  // set the mode/level bit so the next output
        }                       // compare forces the pin high after low_time
}
 
// Pass the required constants through to the assembler:
// Don’t insert any leading spaces on a line that contains an EQU directive.
#asm
TOC3            EQU     $801A
TCTL1           EQU     $8020
TFLG1           EQU     $8023
 
PA5_MASK        EQU     $205
OC3_MASK        EQU     $20
OC3_MODE_MASK   EQU     $20
OC3_LEVEL_MASK  EQU     $10
NOT_OC3_LEVEL_MASK EQU  $EF
 
#endasm
 
 _Q void AssembledOC3Service( void )
// This interrupt service routine performs the same functions as the high level
// service routine named OC3Service.  This alternative interrupt service routine
// is assembly coded to illustrate the principles of assembly coding with
// this environment.  This routine it executes in under 45 usec
// including the call and return overhead. The high level version
// is nearly as fast.
// NOTE: #asm and #endasm in-line assembly directives
//               must be the first on a line,
//  AND:  each line of assembly code MUST START WITH A TAB OR SPACE,
//  BUT:  labels must NOT be preceeded by a tab or space.
//  The comment character for assembly code is the * as shown below.
{
#asm
        ldab TCTL1
        bitb #OC3_LEVEL_MASK    * Look at the OC3/PA5 pin output level
        beq is_low
        * If output just went high, clear the level bit in TCTL1: next OC3 clrs PA5
                andb #NOT_OC3_LEVEL_MASK
                stab TCTL1
                ldd TOC3
                addd high_time
                bra finished
is_low
     * If output just went low, set the level bit in TCTL1: next OC3 sets PA5
                orab #OC3_LEVEL_MASK
                stab TCTL1
                ldd TOC3
                addd low_time
finished
        std TOC3           * update the OC count for the next output compare
        ldaa #OC3_MASK     * Reset the OC3 interrupt flag by writing a 1
        staa TFLG1         * so that new OC3 interrupts will be recognized.
#endasm
}
 
_Q void InstallOC3( void )
// This installation routine enables the pin-control function, ATTACHES the
// service routine, configures PortA pin 5 as an output, initializes the output
// compare register TOC3, clears the OC3 interrupt request flag (thus ignoring
// prior interrupt requests), and locally enables the OC3 interrupt.
// PWM can begin when interrupts are globally enabled.
{
        TMSK1 &= ~OC3_MASK;                 // Disable OC3 interrupts.
        TCTL1 |= OC3_MODE_MASK;
        // Set the OC3 mode bit so that an output compare sets or clears PA5 pin
        // depending on the level bit which is toggled by the interrupt routine.
//      ATTACH(AssembledOC3Service, OC3_ID); // optional assembly service routine
        ATTACH(OC3Service, OC3_ID);          // use the C-coded version
        TCTL1 &= ~OC3_LEVEL_MASK;            // Set to low before pulses start.
        CFORC |= OC3_MASK;                   // and init by forcing a compare.
        TOC3 = TCNT + TIMER_COUNTS_PER_PERIOD;  // start after a min 130ms delay
        TFLG1 = OC3_MASK;                       // clear interrupt flag OC3F
        TMSK1 |= OC3_MASK;                      // set OC3I to locally enable OC3
}
 
// ************************** Statistics Task **************************
 
// This task samples the analog input voltage (see task 1) once per second,
// stores it in a matrix, and calculates and prints the mean and standard
// deviation of the data every 10 seconds.
 
FORTH_ARRAY Last10Voltages;
        // row matrix;  holds 1 voltage per second for past 10 seconds
 
// these index variables keep track of where data is placed in Last10Voltages:
static int matrix_index, last_index;
 
// these hold the derived statistics:
static float mean, standard_deviation;
 
_Q float RowMean(int rownum, FORTH_ARRAY * array_ptr)
// sums the elements in the specified row of the specified matrix and
// divides by the number of elements in the row to calculate the mean.
{       float accumulator = 0.0;
        int i, numcolumns = NUMCOLUMNS(array_ptr);  // see \Mosaic\ARRAY.H file
        for(i=0; i < numcolumns; i++)
                accumulator += FARRAYFETCH(float, rownum, i, array_ptr);
        return (accumulator / numcolumns);
}
 
_Q float RowStandardDeviation(int rownum, FORTH_ARRAY* array_ptr, float row_mean)
// subtracts the row mean from each element and sums the squares of all
// resulting differences in the specified row of the specified matrix
// and takes the square root of the sum to calculate the standard deviation.
{       float accumulator = 0.0, temp;
        int i, numcolumns = NUMCOLUMNS(array_ptr);  // see \Mosaic\ARRAY.H file
        for(i=0; i < numcolumns; i++)
            {   temp = FARRAYFETCH(float, rownum, i, array_ptr) - row_mean;
                accumulator += (temp * temp);
            }
        return sqrt(accumulator);
}
 
_Q void InitFPArray(float value, FORTH_ARRAY * array_ptr)
// stores specified floating point value in each element of the array
// do not use this function to init arrays that hold char, int or long data
{       int r, c,
            numcolumns = NUMCOLUMNS(array_ptr),   // see \Mosaic\ARRAY.H file
            numrows = NUMROWS(array_ptr);
        for(c=0; c< numcolumns; c++)
                for(r=0; r < numrows; r++)
                        FARRAYSTORE(value, r, c, array_ptr);
}
 _Q void CalcStats( void )
// This routine calculates mean and standard deviation of the
// Last10Voltages matrix and stores them in variables.
{
        mean = RowMean(0, &Last10Voltages);                     // row# = 0
        standard_deviation = RowStandardDeviation(0, &Last10Voltages, mean);
}
 
// These routines manage the LCD display.
// The message on the display will look like this:
//      Mean =
//            x.xxx   Volts
//      Standard Deviation =
//            x.xxx   Volts
 
#define  FP_OFFSET      4       // character offset to start of mean or
                                // std.deviation in display line
#define VOLTS_OFFSET 14         // character offset to start of "Volts" label
                                // in display line
 
#define MAX_CHARS_PER_DISPLAY_LINE  40
// large enough for 4x20 character display as well as 16 x 40 graphics display
 
#define SPACE   0x20            // ascii space {blank}
 
#define  DISPLAY_CONFIG_BYTE    ((uchar*) 0xAE1E) // see grphext.c file
#define  TOSHIBA_VS_HITACHI_MASK        0x40      // 1 = toshiba; 0 = hitachi
 
char  linebuffer[MAX_CHARS_PER_DISPLAY_LINE+1];
        // single line buffer to assist in writing to display
        // NOTE: it’s all right if this buffer is longer than the display line;
        //      StrToDisplay() will ignore the extra characters.
 
_Q uint Toshiba(void)
        // returns flag, = true if toshiba display; false if hitachi
{
        return (((*DISPLAY_CONFIG_BYTE) & TOSHIBA_VS_HITACHI_MASK) ? 1 : 0);
}
 
_Q void BlankDisplayString(char* string_base, int numelements)
// writes blanks into the specified string, taking into account that
// Toshiba graphics displays in text mode use 0x00 as the code for BL
// numelements includes the terminating null character
{       int i;
        char blankchar = (Toshiba() ? 0 : SPACE);
        for( i=0; i < (numelements-1); i++)
                string_base[i] = blankchar;
        string_base[numelements-1] = 0; // terminating null
}
 
 _Q void SetupDisplay( void )
        // writes headings to display; leaves numbers blank.
{       xaddr display_buffer_base = DisplayBuffer();
        int numlines = LinesPerDisplay();
        int chars_per_line = CharsPerDisplayLine();
        char blankchar = (Toshiba() ? 0 : SPACE);
        FillMany(display_buffer_base, (numlines * chars_per_line), blankchar);
               // FillMany() blanks the display buffer                                                                                         // blank display buffer
        STRING_TO_DISPLAY("mean = ", 0, 0 );                // line 0
        STRING_TO_DISPLAY("volts", 1, VOLTS_OFFSET);        // line 1
        STRING_TO_DISPLAY("standard deviation =", 2, 0 );   // line 2
        STRING_TO_DISPLAY("volts"”, 3, VOLTS_OFFSET);        // line 3
        UpdateDisplay();                 // write buffer contents to display
}
 
// sprintf(char* s, const char *format, ... ) does formatted write to specified
// string.  Returns #chars assigned,
// not including the terminating null that it writes after the last char.
// Returns a negative number if an error occurs.
 
_Q void ShowStats( void )
 // displays mean and standard deviation of Last10Voltages on LCD display
{       int num_chars_placed;
        BlankDisplayString(linebuffer, MAX_CHARS_PER_DISPLAY_LINE);
        num_chars_placed = sprintf(linebuffer, "%7.3f", mean);
          // use field width = 7 chars; 3 digits to right of the decimal point
        if(num_chars_placed > 0)
                STRING_TO_DISPLAY(linebuffer, 1, FP_OFFSET);     // line 1
        BlankDisplayString(linebuffer, MAX_CHARS_PER_DISPLAY_LINE);
        num_chars_placed = sprintf(linebuffer, "%7.3f", standard_deviation);
        if(num_chars_placed > 0)
                STRING_TO_DISPLAY(linebuffer, 3, FP_OFFSET);    // line 3
        UpdateDisplay();                                 // write to display
}
 
_Q void LogDataAndShowStats( void )
// increments matrix_index every second,
// loads input_voltage data collected by task 1 into Last10Voltages array,
// and displays statistics on LCD display every 10 seconds
{       float latest_input;
          // we need this temporary because we must do an uninterrupted fetch
          // from input_voltage, then pass the result to FARRAYSTORE
        matrix_index = (ReadElapsedSeconds()) % 10;  // 0<= matrix_index <= 9
        if(matrix_index != last_index)          // if a second has elapsed...
                {  latest_input = PeekFloatUninterrupted(&input_voltage);
                   FARRAYSTORE(latest_input, 0, matrix_index, &Last10Voltages);
                                                // store reading in matrix
                   last_index = matrix_index;   // update last_index
                   if(matrix_index == 9)        // if 10 seconds have elapsed...
                           { CalcStats();       // calculate new statistics
                             ShowStats();       // update display
                           }
                }
}
 _Q void Statistics( void )
// this is the activation routine for the statistics task;
// it calculates and displays the mean and standard deviation of the data.
{
        DIM(float, 1, 10, &Last10Voltages);     // dimension as a 1-row array
        InitFPArray(0.0, &Last10Voltages);      // initialize array
        last_index = -1;                        // initialize last_index
        SetupDisplay();                         // write headings to display
        while(1)
           {     LogDataAndShowStats();          // calc and display statistics
                 Pause();
           }
}
 
// ********************* BUILD TASKS  ****************************
 
// Note: we’ll keep the Forth interpreter task active during
// development/debugging, and put it ASLEEP in the final turnkeyed version.
 
// First declare the tasks and allocate their 1K task areas:
// FORTH_TASK (see MTASKER.H) is the default task running QED-Forth;
// this task is automatically built and started upon each reset/restart;
// in the autostart routine FORTH_TASK puts itself ASLEEP so the end
// user can’t run Forth.
 
TASK ReadInputTask;        // data gathering task base xaddr
 
TASK ControlOutputTask;    // PWM task base xaddr
 
TASK StatisticsTask;       // statistics reporting task
 
// BUILD_C_TASK(HeapStart,HeapEnd,Base) and
// ACTIVATE(function_ptr, task_base_addr)
// macros are defined in \mosaic\mtasker.h file.
 
_Q void BuildTasks( void )
// Empties the round robin task loop and then
// carefully builds the tasks every time we start up.
// Note that only the statistics task has access to the heap.
{
        NEXT_TASK = TASKBASE;    // important! empties task loop before building
        SERIAL_ACCESS = RELEASE_ALWAYS; // allow sharing of serial ports
        BUILD_C_TASK(0,0,&ReadInputTask);
        BUILD_C_TASK(0,0,&ControlOutputTask);
        BUILD_C_TASK(DEFAULT_HEAPSTART,DEFAULT_HEAPEND,&StatisticsTask);
}
 
_Q void ActivateTasks( void )
        // associate activation routines with each of the tasks.
{
        ACTIVATE(GatherData, &ReadInputTask);
        ACTIVATE(SetPulseParameters, &ControlOutputTask);
        ACTIVATE(Statistics, &StatisticsTask);
}
 
 // ********************* SET UP AUTOSTART ROUTINE *********************
 
// We’ll designate the top level word main as the PRIORITY.AUTOSTART routine.
// Every time the QVGA Controller is powered up or reset, the main routine will
// automatically be executed by the default FORTH_TASK
// main() zeros the variable area and initializes the heap.
// During debugging, the FORTH task which runs main() has access to
// all defined function names declared using the _Q keyword;
// the names are sent to the QVGA Controller via the .DLF download file.
// This helps to debug the program.
// main() initializes the elapsed time clock, installs the
// OC3 interrupt service routines, and builds and activates the tasks.
// It releases control of the serial line, starts the timeslicer, and PAUSEs
// to begin execution of the application.
// After debugging is complete, the optional commands which
// specify a COLD restart and which put the FORTH_TASK ASLEEP can be inserted;
// these commands are commented-out in the code shown here.
 
_Q void InitVariables(void)
{       // init static variables & strings at runtime, and delete array
        // to clean up the heap before allocating heap items
        input_voltage = 0;
        high_time = low_time = 0;
        DELETED(&Last10Voltages);
        matrix_index = last_index = 0;
        mean = standard_deviation = 0.0;
        BlankDisplayString(linebuffer, MAX_CHARS_PER_DISPLAY_LINE);
}
 
void main(void)
        // this is the highest level routine in the turnkeyed application.
{
        InitVariables();        // init variables, delete arrays
        INIT_DEFAULT_HEAP();    // it’s important to init heap at startup
        InitElapsedTime();      // initialize qed elapsed time clock
        InstallOC3();           // install service routine for pwm generation
        BuildTasks();           // initialize user areas of the tasks
        ActivateTasks();        // associate action routine with each task
// the following 2 commands are removed during debugging;present in final version
        //  ColdOnReset();      // ensures full initialization upon each reset
        //  STATUS = ASLEEP;    // puts forth task asleep;
        RELEASE(SERIAL);        // in case another tasks needs to use serial
        StartTimeslicer();      // starts elapsed time clock, enables interrupts
        Pause();                // start next task immediately
}
 
// Now from your terminal, type:
//   CFA.FOR  main    PRIORITY.AUTOSTART
 
// this will install main() as the routine that is automatically executed
// each time the board is reset or powered on.
 // The PRIORITY.AUTOSTART routine initializes the priority.autostart vector
// at locations 7FFA-7FFF on page 4 which will be in Flash.
 
// Then upon the next restart the main() routine will automatically execute.
// NOTE:   To erase the autostart vector and return to QED-Forth,
//         type at the terminal:
//                      NO.AUTOSTART
//         If you have put the FORTH_TASK asleep so that it does not
//         respond to the terminal,
//         activate the Special Cleanup Mode by turning on dip switch #6, toggling
//         dip switch #7, and then restoring switch #6 to its original position.
//         The Special Cleanup Mode erases the autostart vector and restores the
//         board to a pristine condition (it also sets the default
//         baud rate to 9600, and the LCD display type to 4x20 character
//         display; use Baud1AtStartup() and IsDisplay() if you need to
//         change these defaults).
//
// ******************* BURNING THE FINAL APPLICATION FLASH ******************
 
// To generate a Flash device that contains this application, download the
// download the TURNKEY.DLF file, and execute the
//  CFA.FOR MAIN  PRIORITY.AUTOSTART
// command to install the autostart vector.
// Before resetting the board or typing main (which could put FORTH asleep
// and make communications difficult), we’ll make an image of page 4
// which holds the object code and autostart vector:
// To make a Motorola S2-record file to send to the Flash Programmer,
// set your terminal to capture incoming text to a disk file using the
// "Save File" menu item, and interactively type from the terminal:
//      HEX  0 4  DIN 0  8000  DUMP.S2
// Close the file when the dump terminates, and use Textpad to remove
// any extraneous file contents such as the DUMP.S2 command and Forth’s
// "ok" prompts.  Then send the resulting file to a Flash Programmer.
// Power up the QVGA Controller and it will automatically run the application!