lab10.cpp

00001 #include "mbed.h"
00002 #include "TextLCD.h"
00003 BusOut leds(D14,D15);//creates a global busout that identifies the pins associated with the leds. 
00004 bool keycode();//Function prototype for the function that checks if the correct keycode was entered(returns boolean)
00005 float readtempurature(AnalogIn *temp);//function prototype fot the readtempurature function(this function was done by ben)
00006 char scan4by3keypad(BusIn* col, BusOut* row, const char k[4][3]); //function prototype for the scan4by3keypad function(returns a char) 
00007 TextLCD lcd(D6, D5, D4, D3, D2, A0); // creates a global object of the TextLCD class called lcd with the pins D6,D5,D4,D3,D2,A0 assigned. These pins correspond to the pins rs, e, d4-d7 on the lcd  
00008 char usercode[4] = {' ',' ',' ',' '};//creates a global char array that is used to store the entered code. This array is initialized to nothing 
00009 /************************************************************************************
00010 Main function:
00011 Purpose: The purpose of the main function is to determine the usercode entered from the keypad. If the code is correct the function will light the green
00012 led, print access granted, and then the temperature to the LCD display. if the code entered is incorrect, the function will prompt the user to try again and light the red LED.
00013 
00014 Pins declared:
00015 temp(A1,AnalogIn): This pin is used to bring the value of the thermistor onto the nucleo board since it is an analog value the pin is declared as AnalogIn.
00016 rowpins(D13,D12,D11,D10, BusOut): These pins are declared as a bus out and are connected to the row pins of the keypad. The pins will be used to turn the bus pins high.
00017 columnpins(D9,D8,D7, BusIn): These pins are declared as a bus in and are connected to the column pins of the keypad. The pins are used to read the state of the column pins to determine if a key has been pressed.
00018 
00019 Variables:
00020 button(const char): a 4 by 3 array that is used to store the char equivalent to the keys on the keypad.
00021 access(bool): a boolean variable that is true if the code entered is correct, and is false if the code entered is incorrect.
00022 
00023 Functions: 
00024 lcd.cls(): a function of the lcd class that will clear the lcd display
00025 lcd.printf(""):a function of the lcd class that will print to the lcd display
00026 lcd.locate(c,r): a function of the lcd class that will move the cursor to the column(c) and row(r) on the lcd that is specified. 
00027 scan4by3keypad(&columnpins, &rowpins, button):a function created previously that accepts the addresses of the row and column pins as well as the value of the button array. This function returns the char representing
00028 the button pressed.
00029 wait(x): waits x amount of seconds then continues with the function.
00030 if(condition){}:the if statement will run the code contained in the curly brackets if the condition is met
00031 else{}: the else statment is attached to an if statement and runs the code contained in the curly brackets if the condition of the if statement is not met
00032 leds[x].write(y):writes y(either a 1 or 0) to the pin at the position x in the leds busout. 
00033 while(condition){}:continues to loop through the code contained in the curly brackets while the condition is met. The loop will be broken if the condition is not met. 
00034 for(;;){}: runs the code contained in the brackets forever and ever.
00035 readtempurature(&temp): A function created by Ben that returns a value of type float representing the temperature. This function accepts the address of the temp pins. 
00036 *************************************************************************************/
00037 int main() {
00038      AnalogIn temp (A1);//indentifies the pin A1 as an analogin pin named temp
00039      BusOut rowpins(D13,D12,D11,D10);//busout for my row pins
00040     BusIn columnpins(D9,D8,D7);//busin for my colummn pins
00041     columnpins.mode(PullDown);//enables the internal pulldown for the column pins
00042     const char button[4][3]= {{'1','2','3'},
00043                              {'4','5','6'},
00044                              {'7','8','9'},
00045                              {'4','0','#'}};//array which helps determine which button was 
00046 bool access = false;//boolean variable that will change depending on whether the keycode is correct or incorrect. 
00047     while(access == false)//loops through this code while the access is false (keycode entered is wrong)
00048     {
00049         lcd.cls();//clears the LCD display
00050         lcd.printf("Enter Code:\n");//prints "enter code" to the LCD display.
00051         lcd.locate(11,0);//moves the cursor to the 11th column of the 0th row on the lcd display
00052         usercode[0] = scan4by3keypad(&columnpins, &rowpins, button);//sets the first value of usercode to the char returned by the scan4by3keypad function.
00053         lcd.printf("*");//prints a * to the lcd at the 11th column of the 0th row ro show that a value has been entered into the usercode
00054         wait(0.5);//waits half a second
00055         usercode[1] = scan4by3keypad(&columnpins, &rowpins, button);//sets the second value of usercode to the char returned by the scan4by3keypad function.
00056         lcd.locate(12,0);//moves the cursor to the 12th column of the 0th row on the lcd display
00057         lcd.printf("*");//prints a * to the lcd at the 12th column of the 0th row ro show that a value has been entered into the usercode
00058         wait(0.5);//waits half a second
00059         usercode[2] = scan4by3keypad(&columnpins, &rowpins, button);//sets the third value of usercode to the char returned by the scan4by3keypad function.
00060         lcd.locate(13,0);//moves the cursor to the 13th column of the 0th row on the lcd display
00061         lcd.printf("*");//prints a * to the lcd at the 13th column of the 0th row ro show that a value has been entered into the usercode
00062         wait(0.5);//waits half a second.
00063         usercode[3] = scan4by3keypad(&columnpins, &rowpins, button);//sets the fourth value of usercode to the char returned by the scan4by3keypad function.
00064         lcd.locate(14,0);//moves the cursor to the 14th column of the 0th row on the lcd display
00065         lcd.printf("*");//prints a * to the lcd at the 14th column of the 0th row ro show that a value has been entered into the usercode
00066         wait(1);//waits one second
00067         if(keycode() == true)//if the keycode is correct this code will run (breaks the loop)
00068         {
00069             lcd.cls();//clears the lcd completely
00070             lcd.locate(0,0);//moves the cursor to the 0th column of the 0th row of the LCD
00071             lcd.printf("Access granted!\n");//prints "Access granted" to the LCD
00072             leds[0].write(1);//writes 1 to the 0th value of the leds busout. (green LED)
00073             wait(1);//waits one second
00074             leds[0].write(0);//writes 0 to the 0th value of the leds busout. (green LED)
00075             access = true;//sets access to true which breaks the while loop. 
00076         }
00077         else//if the keycode is not correct this code will run (does not break the loop)
00078         {
00079             lcd.cls();//clears the lcd completely
00080             lcd.locate(0,0);//moves the cursor to the 0th column of the 0th row of the LCD
00081             lcd.printf("Access Denied!");//prints "Access Denied!" to the LCD display
00082             leds[1].write(1);//writes 1 to the 1st value of the leds busout(red led)
00083             wait(1);//waits one second
00084             leds[1].write(0);//writes 0 to the 1st value of the leds busout(red led)
00085 
00086         }
00087     }
00088     for(;;)//infinite loop
00089     {
00090         lcd.locate(0,1);//moves the cursor to the 0th column of the first row on the LCD
00091         lcd.printf("Temp: %.2f",readtempurature(&temp));//prints the value returns by the readtempurature function.(.2f will cutoff the value after the second decimal place.
00092         wait(1.5);//waits 1.5 seconds as to no make the display look all glitchy.
00093     } 
00094  }  
00095 /********************************************************************************
00096 keycode function:
00097 purpose: The purpose of this function is compare the value of the global array usercode to the correct codes specified by the PM. this function returns true if the code is one of the correct codes and will 
00098 return false if the code is not correct. 
00099 
00100 Passed variables: 
00101 None
00102 
00103 Returned variables: 
00104 status(bool)
00105 
00106 Pins Declared: 
00107 None
00108 
00109 variables:
00110 status(bool): a boolean variable that will be set true if the keycode is correct, the variable will be set to false if the keycode is incorrect.
00111 usercode[]:A global array containing the user entered code. 
00112 
00113 functions:
00114 if(condition){}:the if statement will run the code contained in the curly brackets if the condition is met
00115 return:returns the variable or value to the function that this function was called from.
00116 ********************************************************************************/
00117 bool keycode()
00118  {
00119     bool status = false;//creates a boolean variable called status that is initialized to false
00120     if(usercode[0] == '1' && usercode[1] == '2' && usercode[2] == '3' && usercode[3] == '4'||//if usercode array is 1234 or 4321 or 0000
00121        usercode[0] == '4' && usercode[1] == '3' && usercode[2] == '2' && usercode[3] == '1'||
00122        usercode[0] == '0' && usercode[1] == '0' && usercode[2] == '0' && usercode[3] == '0')
00123     {
00124         status = true;//sets status to true
00125     }
00126     return status;//returns the value of status.
00127 }
00128 /*************************************************
00129 scan4by3keypad function:
00130 function: This function will loop through rows turning each row high and then reads the columns and if that column is high
00131 it can determine which button was pressed. This uses blocking polling. 
00132 
00133 variables:
00134 row (BusOut): creates the busout for my row pins
00135 col (BusOut): creates a busout for my column pins
00136 k (const char): an array containing the values of the buttons to be used when printing what button was pressed
00137 buttonpressed (char): a char buffer which stores the char value at the point in the k array depending what button is pressed.
00138 j (int): loop condition associated with my row pins
00139 isbuttonpressed (int): This int is the while loop condiition. 
00140 
00141 functions:
00142 pin->write(0b0001<<j): will write the byte to the pins specified and will shift depending on what value j is
00143 pin->read(): reads from the associated pin(s)
00144 printf(): prints to the terminal
00145 switch col->read(): will look at the case associated with what returns from the column read.
00146 while(condition): will keep looping what is inside of the loop until the condition is not met. This is used for my blocking polling. 
00147 ****************************************************/
00148 char scan4by3keypad(BusIn* col, BusOut* row, const char k[4][3])
00149 {       char buttonpressed;
00150         int isbuttonpressed=0;
00151     while(isbuttonpressed==0)
00152     {     
00153         for(int j=0;j<4;j++)//loops j which will be used to turn the rows on
00154         {
00155             row->write(0b0001<<j);//writes a 1 to the jth pin
00156             switch (col->read())
00157             {
00158                 case 0b001://if the first column is high
00159                 buttonpressed = k[j][0];//equals the array at the jth and zero position.
00160                 isbuttonpressed=1;//breaks the while loop
00161                 break;
00162                    case 0b010://if the second column is high
00163                 buttonpressed = k[j][1];//equals the array at the jth and one position.
00164                 isbuttonpressed=1;//breaks the while loop
00165                 break;
00166                    case 0b100://if the third column is high
00167                 buttonpressed = k[j][2];//equals the array at the jth and second position
00168                 isbuttonpressed=1;//breaks the while loop
00169                 break;
00170             }   
00171             row->write(0b0001<<j);//resets the jth pin low so there is no confusion as to what button is pressed
00172         }
00173      } 
00174     return buttonpressed;//returns the char value stored in the array  
00175 }
00176 /**********************************************************************************************************
00177     Description: The purpose of this function is to calculate the temperature being read by the thermistor
00178         In order for this code to work, you must connect a 10k resistor in series with the thermistor. The wire from A1 on the nucleo f411RE must be connected after the resistor.  The voltage being used in this circuit is 3.3V.
00179         Below you will find a rough drawing of what the circuit should look like 
00180         
00181                  3.3V---------Resistor---wire from A1-------Thermistor-------GND
00182     
00183     Parameters:
00184            
00185             temp->Defines the analog input pin used to measure the voltage of the thermistor
00186                           
00187             
00188     Returns:
00189             celcius: Returns the tempurature measured by the thermistor in degrees celsius as a float value
00190 **********************************************************************************************************/
00191 float readtempurature(AnalogIn *temp)
00192 {
00193     float tempVal; //variable that stores the voltage reading of the thermistor as a value between 1 and zero 
00194     tempVal=temp->read(); //reads the voltage of the thermistor on analog pin 1 of the nucleo f411RE
00195     float vrt; //variable that stores the actual value of the voltage of the thermistor
00196     vrt=(tempVal*3.3);//this formula determines the actual voltage of the thermistor
00197     float top;//variable that defines the numerator of the formula to determine the resistance of the thermistor
00198     top=(vrt*10000);//numerator of the formula used to determine the thermisistor resistance
00199     float bottom; //variable that defines the denominator of the formula to determine the resistance of the thermistor
00200     bottom=(3.3-vrt); //denominator of the formula to determine the thermisistor resistance
00201     float rt=(top/bottom);//this is the formula to determine the thermisitor resistance
00202     float A=(3.354016e-3);//Constant A1 in the formula used to calculate the temperature given the resistance of the thermisitor
00203     float B=(2.569650e-4);//Constant B1 in the formula used to calculate the temperature given the resistance of the thermisitor
00204     float C=(2.620131e-6);//Constant C1 in the formula used to calculate the temperature given the resistance of the thermisitor
00205     float D=(6.383091e-8);//Constant D1 in the formula used to calculate the temperature given the resistance of the thermisitor
00206     float ln1=(log(rt/10000)); //First ln operation in the formula used to calculate the temperature given the resistance of the thermisitor
00207     float ln2=log(pow((rt/10000),2));//Second ln operation in the formula used to calculate the temperature given the resistance of the thermisitor
00208     float ln3=log(pow((rt/10000),3));//Second ln operation in the formula used to calculate the temperature given the resistance of the thermisitor
00209     float denominator=(A+(B*ln1)+(C*ln2)+(D*ln3)); //complete denominator of the formula used to calculate the temperature given the resistance of the thermisitor
00210     float  celcius=((1/denominator)-273.15);//completed formula to calculate the tempurature given the resistance of the thermisitor
00211     
00212     return celcius; //returns the value of the tempurature in degrees celsius
00213 }