Project description: This is a “multitasking clock” project that displays the current time in different cities by allowing the user to choose one city of 10 choices of cities that are displayed on a menu on PC screen, and the choice made is displayed on the LCD as: chosen city name on the first line along with its current time on the second line. Initially the LCD displays London and its current time as default until user selects a different city to be displayed.
Files Description with functions: Main.C: Global variables: cities: a 2D character array to store cities names. timediff: an array to store time difference of each city. currentcity: an integer that represents the currently selected city inputted by the user Message: a structure that contains 3 unsigned char variables, hours, minutes and seconds.
Main function(): creates 2 queues, queue 1 which will be used by task 1 to send messages to task 2, and queue 2 which will be used by task 3 to send messages to task1. After creating the queues, we create 3 tasks and start the scheduler.void Task1(void *pvParameters): responsible for incrementing the time, we first create Tim, a variable of type Message, and then we receive from task 3 the time initially. Then in the for loop, we delay the function for 1 second and then we increment the time, we add 1 second to the seconds and check if the seconds exceeded 60, we then make it equal 0 and increment the minutes, and so on.
void Task2(void *pvParameters): responsible for printing on the LCD, initially we create time, initialize LCD and clear its display, then in the for loop we receive the time from task 1 after getting incremented, we display it on the lcd, we then write the city name in the first column. After that we add the time difference using the time diff array (and check if the hours exceed 24 then we subtract 24), we then print the hours, a colon, the minutes, a colon, the seconds and of course we check if there is a zero in the leftmost digit, if there is not, we add a zero.
void Task3(void *pvParameters): Responsible for interacting with the user, we first create time, initialize the UART and a character array time which will carry the time inputted. we then read the time from the user by using the function read_time(), after that we put this time inside Tim structure, and send it to queue2. In the for loop we let the user select a city by calling the function read_selection(), where an integer is inputted.
void ReadTime(char time[]): We create an unsigned character, which is sent by the uart, if the input is enter we break from the while loop, after that this input is moved to an array and the index is incremented.int ReadSelection(): We create an unsigned character, which is sent by the UART, if the input is enter we break from the while loop, the input is then changed into a number and returned from the function.
lcd_drivers.h: the file contains the functions prototypes Implemented in the lcd_driver.c file
UART.h: the file contains the functions prototypes Implemented in the UART.c file UART.c: the file contains the functions implementations used for UART
void PrintString(char *out_message): This function prints a string on terminal of putty using UART.
lcd_driver.c: the file contains the functions implementations used for lcd.
void LCD_init(); This function is used to initialize the LCD by outputting the pins and using the D4 to D7 only as we will use only 4-bits. void LCD_Clear(void): This function clears the lcd using LCD_Command(0x01). void LCD_writeCharWithPos(unsigned char d, char x, char y):This function prints a given character with selected position on the 16x2 lcd. void LCD_PrintLn(char i, char *s): This function prints a given string on a requested line