assignment_2_herpe
Dependencies: mbed WattBob_TextLCD MCP23017
Diff: main.cpp
- Revision:
- 0:aaddc17011a9
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/main.cpp Thu Mar 08 16:32:35 2012 +0000 @@ -0,0 +1,429 @@ +// XAVIER HERPE Assignment 2 +// 5th year Robotics & Cybertronics +// Heriot-Watt University + +#include "mbed.h" +#include "MCP23017.h" +#include "WattBob_TextLCD.h" +#include "SDFileSystem.h" +#include "FATFileSystem.h" + +#define BACK_LIGHT_ON(INTERFACE) INTERFACE->write_bit(1,BL_BIT) +#define BACK_LIGHT_OFF(INTERFACE) INTERFACE->write_bit(0,BL_BIT) + +// Pointers to LCD screen and SD card +MCP23017 *par_port; // pointer to 16-bit parallel I/O chip +WattBob_TextLCD *lcd; // pointer to 2*16 character LCD object +FILE *fp; // Pointer to SD card object + + +//===================================================================================== +// I/O ports allocation +//===================================================================================== +DigitalIn TTL(p17); // TTL input for frequency measurement +DigitalIn switch_1(p18); // Switch 1 input +DigitalIn switch_2(p19); // Switch 2 input +DigitalIn switch_off(p11); // Switch used to close SD file and stop cyclic executive +AnalogIn analogue_in_1(p15); // POT value +AnalogIn analogue_in_2(p16); // LDR value +PwmOut servo(p21); // Servo output +DigitalOut TestPin(p20); // Pin only used to test program and measure time +SDFileSystem sd(p5, p6, p7, p8, "sd"); // The pinout on the mbed Cool Components workshop board + + +//===================================================================================== +// Internal objects declaration +// ==================================================================================== +BusOut LEDs(LED4, LED3, LED2, LED1); // Address the four LEDs to a single bus +Timer timer; // Timer used to measure frequency in task 1 +Timer DoNothing; // Timer used to measure how long the program does nothing +Ticker ticker; // Ticker used as clock for cyclic executive program + + +//===================================================================================== +// Constants declaration +//===================================================================================== +const int SampFreq = 100; // Sampling frequency is 10kHz (100us) + + +//===================================================================================== +// Variables declaration +//===================================================================================== + +// Variables for cyclic executive program +long int ticks = 0; // Used to define what task to call in the cyclic executive program +int NoTask = 0; // Used to return how long the program does nothing in ms +int NoTaskCount = 0; // Variable incremented until one total cycle of 10 seconds is reached + +// Variables for tasks 1 and 2 +int period = 0; // Returned period of the TTL input signal +int frequency = 0; // Returned frequency of the TTL signal + +// Varibles for task 4 +int switch_1_val = 0; // Used to return how many times the switch is high +int switch_2_val = 0; +bool switch_1_state = 0; // Used to define whether the debounced switch is ON or OFF +bool switch_2_state = 0; + +// Variables for task 5 +float analogue_1_val = 0; // Used to return the filtered analogue input +float analogue_2_val = 0; + +int analogue_1_int = 0; // Used to convert float to int (results in quicker display on LCD in task 6) +int analogue_2_int = 0; + +// Variable for task 7 +int LogCount = 0; // Used to define logging number + +// Variable used for task 8 +int BinCount = 0; // Used to increment a binary display on LEDs. Goes from 0 to 15 and then is reset +bool BinEnable = 0; // Used to tell task 5 to display binary pattern on LEDs every 1.5s +int IncCheck = 0; // Check increment to see if 6 cycles have elapsed to light LEDs ( 6 * 250us = 1.5s) + + +//===================================================================================== +// Task declaration +//===================================================================================== + +void CyclEx(); + +void Task1(); // Measure TTL input frequency +void Task2(); // Show frequency on LCD screen +void Task3(); // Show speed on servo dial +void Task4(); // Read and debounce two digital inputs +void Task5(); // Read and filter two analogue inputs +void Task6(); // Display digital and analogue inputs on LCD screen +void Task7(); // Log speed, analogue and digital inputs on SD card +void Task8(); // Display error message on LCD screen and display binary pattern on LEDs + +void WaitRisEdge(); // Subroutine to detect rising edge +void WaitFalEdge(); // Subroutine to detect falling edge + +void Stop(); // Close log file and stop cyclic executive + + +//===================================================================================== +// Main program +//===================================================================================== + +int main() +{ + + // LCD Screen Initialisation + par_port = new MCP23017(p9, p10, 0x40); // initialise 16-bit I/O chip + lcd = new WattBob_TextLCD(par_port); // initialise 2*26 char display + par_port->write_bit(1,BL_BIT); // turn LCD backlight ON + lcd->cls(); // clear display + + // EXEL log file initialisation + fp = fopen("/sd/log.xls", "w"); // pointer to log in text file called "log". (Use "a" to not delete file) + fprintf(fp, "This file is the property of Xavier Herpe, the French\n\n"); + + // DoNothing timer reset + DoNothing.reset(); + + // Internal ticker set to 25ms. Every 25ms, the scheduler is called and selects the task to run + ticker.attach(&CyclEx, 0.025); // Period set to 25ms + while(1)// Run until system shuts down + { + + } +} + +// Where tasks are scheduled based on an EXEL sheet +void CyclEx() +{ + // Stop timer when a new task starts + DoNothing.stop(); + + if(ticks % 80 == 4) // Occures every 80 clock cycles (2 seconds). Starts with an offset of 4 clock cycles + { + Task1(); + } + + else if(ticks % 200 == 8) // Occures every 200 clock cycles (5 seconds). Starts with an offset of 8 clock cycles + { + Task2(); + } + else if(ticks % 240 == 7) // Occures every 240 clock cycles (6 seconds). Starts with an offset of 7 clock cycles + { + Task3(); + } + else if(ticks % 4 == 0) // Occures every 4 clock cycles (0.1 seconds). Starts with an offset of 0 clock cycles + { + Task4(); + } + else if(ticks % 10 == 1) // Occures every 10 clock cycles (0.25 seconds). Starts with an offset of 1 clock cycles + { + Task5(); + } + else if(ticks % 40 == 3) // Occures every 40 clock cycles (1 seconds). Starts with an offset of 3 clock cycles + { + Task6(); + } + else if(ticks % 400 == 10) // Occures every 400 clock cycles (10 seconds). Starts with an offset of 10 clock cycles + { + Task7(); + } + else if(ticks % 160 == 6) // Occures every 160 clock cycles (4 seconds). Starts with an offset of 6 clock cycles + { + Task8(); + } + + if (switch_off == 1) // Pin used to log data on SD card and stop Cyclic executive program + { + Stop(); + } + ticks++; + + // Start timer when one task is ended + DoNothing.start(); + NoTaskCount++; + + // When one full cycle of 10 seconds is finished, return how long the program was doing nothing (lazy program) + if (NoTaskCount == 400) + { + NoTask = DoNothing.read_ms(); + NoTaskCount = 0; + DoNothing.reset(); + } +} + + +//===================================================================================== +// Tasks +//===================================================================================== + +// Task 1: Measure TTL input frequency +void Task1() +{ + timer.reset(); + + // If the input signal is low, wait for a rising edge to start counting + if (TTL == 0) + { + WaitRisEdge(); // Call subroutine to wait for rising edge + timer.start(); // Start timer + while(TTL == 1) // Keep counting as long as signal is high + { + wait_us(SampFreq); + } + } + + // If the input signal is high, wait for a falling edge to start counting + else if (TTL == 1) + { + WaitFalEdge(); // Call subroutine to wait for falling edge + timer.start(); // Start timer + while(TTL == 0) // Keep counting as long as signal is high + { + wait_us(SampFreq); + } + } + + timer.stop(); // Stop counting when signal changes + period = timer.read_us()*2; // Convert the time into a period + frequency = 1000000/period; // Convert the period into a frequency +} + + + +// Task 2: display the measured frequency on LCD screen +void Task2() +{ + lcd->cls(); // clear display + lcd->locate(0,0); // set cursor to location (0,0) - top left corner + lcd->printf("%d Hz",frequency); // print the frequency calculated in task 1 +} + + + +// Task 3: show speed on servo output dial +void Task3() +{ + servo.period(0.02); // servo requires a 20ms period + // To rotate the servo from -90 to +90 degrees, the pulse width must varies between 600us to 2300us + // The pulse width is calculated from the speed measured in task one + // 50Hz is equivalent to -90 degrees and 100Hz is equivalent to 90 degrees + // 1Hz change is equal to 34us pulse width change, so pulse width = ((frequency - 50)*34) + 600 + servo.pulsewidth_us(2300-((frequency - 50)*34)); + wait_ms(1); // Leave the servo some time to reach its position +} + + + +// Task 4: Read two digital inputs (debounced) +void Task4() +{ + switch_1_val = 0; + switch_2_val = 0; + + // Read each switch three consecutive times with 100us between readings + for(int i=0; i<3; i++) + { + if (switch_1 == 1) // Increment variable if switch 1 is pressed + { + switch_1_val++; + } + + if (switch_2 == 1) // Increment variable if switch 2 is pressed + { + switch_2_val++; + } + + wait_us(SampFreq); + } + // Check how many times switch 1 has been high + // if it has been high more than twice, then switch 1 state = 1 + if (switch_1_val > 1) + { + switch_1_state = 1; + } + else + { + switch_1_state = 0; + } + + // Check how many times switch 1 has been high + // if it has been high more than twice, then switch 2 state = 1 + if (switch_2_val > 1) + { + switch_2_state = 1; + } + + else + { + switch_2_state = 0; + } +} + + + +// Task 5: Read two analogue inputs (filtered) +void Task5() +{ + analogue_1_val = 0; // Reset variables + analogue_2_val = 0; + + // Takes four readings of each analogue input. Readings occure every 0.1ms + // Because the analogue.read() function returns a value from 0 to 1, + // we need to multiply the readings by 3.3 to cover 0V to 3.3V + for(int i=0; i<4;i++) + { + analogue_1_val = analogue_1_val + (analogue_in_1*3.3); + analogue_2_val = analogue_2_val + (analogue_in_2*3.3); + wait_us(SampFreq); + } + + analogue_1_val = (analogue_1_val / 4); + analogue_2_val = (analogue_2_val / 4); + + analogue_1_int = analogue_1_val * 10; // Convert floating point into an integer to reduce display delay + analogue_2_int = analogue_2_val * 10; + + // This section of task 5 is used to take over part of task 8. + // Since the LEDs pattern has to be incremented every 1.5s, the pattern is + // incremented every 6 cycles, which correspond to 1.5s. + if(BinEnable == 1) + { + IncCheck++; + + if(IncCheck == 6) // Corresponds to 1.5s. Increment binary pattern + { + LEDs = BinCount; + BinCount++; + IncCheck = 0; + + if (BinCount > 15) // Used to reset variable once maximum 4-bit binary value is reached + { + BinCount = 0; + } + } + } +} + + + +// Task 6: Display analogue and digital values on LCD screen +void Task6() +{ + // lcd->cls(); // clear display (takes too long) + lcd->locate(0,0); // set cursor to location (0,0) - top left corner + lcd->printf("%d %d%d%d",analogue_1_int,analogue_2_int,switch_1_state,switch_2_state); +} + + + +// Task 7: Log values on SD card +void Task7() +{ + LogCount++; //Used to print the logging number in file. Starts from 1 + fprintf(fp, "Log: %d, Speed: %dHz, Switch_1: %d, Switch_2: %d, POT: %.2fVolts, LDR: %.2fVolts\n",LogCount,frequency,switch_1_state,switch_2_state,analogue_1_val,analogue_2_val); +} + + + +// Task 8: Show error message and light LEDs +void Task8() +{ + // If switch_1 = 1 and POT value > 3V, display error message + if(switch_1_state == 1 && analogue_1_val > 3) + { + //lcd->cls(); // clear display + lcd->locate(0,0); // set cursor to location (0,0) - top left corner + lcd->printf(".ERREUR"); + } + + // If switch 2 is high, return a command to task 5 to do the incrementing pattern every 1.5 seconds + if(switch_2_state == 1) + { + BinEnable = 1; + } + + // If switch 2 is low, stop sending a command to task 5 and light off LEDs + else + { + LEDs = 0; + BinEnable = 0; + BinCount = 0; + } +} + + + +// Stop function to stop cyclic executive and close log file +void Stop() +{ + ticker.detach(); + fprintf(fp, "\n The program did nothing for %d ms, which corresponds to %d percent of the time \n",NoTask, NoTask/100); + fprintf(fp, "\n PROGRAM STOPPED"); + fclose(fp); + +} + + + +//===================================================================================== +// Subroutines +//===================================================================================== + +// Wait for rising edge +void WaitRisEdge() +{ + // As soon as it gets high, the subroutine will end and the timer will start + while(TTL == 0) + { + wait_us(SampFreq); + } +} + + +// Wait for falling edge +void WaitFalEdge() +{ + // As soon as it gets low, the subroutine will end and the timer will start + while(TTL == 1) + { + wait_us(SampFreq); + } +} \ No newline at end of file