1. Add three more LEDs to PC1, PC2 and PC3. Modify the code so that when any switch is pressed the corresponding LED flashes for 2 seconds. If switch 1 is pressed, LED 1 flashes, if switch 2 is pressed, LED 2 flashes etc. Remove the LCD from the code.

2.Modify the code so that A keypad is interfaced which permits users to enter a PIN number. If a known sequence of numbers is entered in correct order, a door in unlocked for 4 seconds. No display is shown on LCD during this time. If an incorrect PIN number is entered the system displays the dialog "INCORRECT PIN" for 3 seconds, and then returns to the default display. The default display is "ENTER PIN NUMBER". In the default state, the entered numbers are displayed as * and after four entries, one of the states above is entered.

#include #include void LCDstr (char *strg); void LCDinit(void); char DefaultMessage[] = "I love Embedded Systems"; char Switch1[] = "Switch 1 is active"; char Switch2[] = "Switch 2 is active"; char Switch3[] = "Switch 3 is active"; char Switch4[] = "Switch 4 is active"; Strobe(); Clear_Display(); Unpack_To_PortD(char data); Short_Delay(); Port_Init(); FlashLED(); void main(void) { LCDinit(); Port_Init(); Clear_Display(); LCDstr (DefaultMessage); delay_ms(1500); Clear_Display(); while(1) { PORTB = PORTB & 0b11111110; // Lower PB0 PORTB = PORTB | 0b00000010; // Raise PB1 if ((PINB & 0b00000100)==0) { LCDstr (Switch1); // Display switch 1 active FlashLED(); // Flash LED once delay_ms(100); Clear_Display(); } if ((PINB & 0b00001000)==0) { LCDstr (Switch2); // Display switch 2 active FlashLED(); // Flash LED twice FlashLED(); delay_ms(50); Clear_Display(); } PORTB = PORTB & 0b11111101; // Lower PB1 PORTB = PORTB | 0b00000001; // Raise PB0

if ((PINB & 0b00000100)==0) { LCDstr (Switch3); // Display switch 3 active FlashLED(); // Flash LED three times FlashLED(); FlashLED(); Clear_Display(); } if ((PINB & 0b00001000)==0) { LCDstr (Switch4); // Display switch 4 active FlashLED(); // Flash LED four times FlashLED(); FlashLED(); FlashLED(); Clear_Display(); } } } void delay_ms(int d) { _delay_ms(50); } void LCDinit(void) // Initialize LCD { DDRD = 0xFF; // Port D is output PORTD = 0x00; // E = 0 delay_ms(5); // Wait for LCD PORTD = PORTD & 0x0F; // mask away high nibble from Port D PORTD = PORTD | 0x20; // enable 4-bit data transfer Strobe(); Unpack_To_PortD(0x28); // enable 4-bit data transfer Unpack_To_PortD(0x0C); // display on, no cursor Unpack_To_PortD(0x06); // cursor shifts right Clear_Display(); } void LCDstr(char *strg) // Output a string of characters { char character; // Exits loop when character = NULL PORTD = PORTD | 0b00000100; // E = 1 PORTD = PORTD & 0b11111101; // RW = 0, PORTD = PORTD | 0b00000001; // RS = 1 (Data) while (character = *strg) { Unpack_To_PortD(character); // write data to LCD *strg++; } } Strobe() { PORTD = PORTD | 0b00000100; // E = 1 Short_Delay; PORTD = PORTD & 0b11111011; // E = 0 delay_ms(1); } Clear_Display() { PORTD = PORTD | 0b00000100; // E = 1 PORTD = PORTD & 0b11111100; // RW = 0, RS = 0 (Cmd) Short_Delay(); // Wait for LCD Unpack_To_PortD(0x01); // clear LCD

Unpack_To_PortD(0x02); // cursor home } Short_Delay() { char i; for (i=0; i<2; i++){}; } Unpack_To_PortD(char data) { char temp; temp = data; PORTD = PORTD & 0x0F; // mask away high nibble from Port D data = data & 0xF0; // mask away low nibble from data PORTD = PORTD | data; // data low nibble to Port D high nibble Strobe(); PORTD = PORTD & 0x0F; // mask away high nibble from Port D temp = temp <<4; // move data low nibble to high nibble PORTD = PORTD | temp; // data low nibble to Port D high nibble Strobe();} FlashLED() { PORTC = PORTC | 0b00000001; delay_ms(250); PORTC = PORTC & 0b11111110; // Flash LED once delay_ms(250); }Port_Init(){ DDRB = DDRB | 0b00000011; // PortB0 and PB1 are outputs PORTB = PORTB & 0b00000000; // PortB0 and PB1 are 0 DDRC = DDRC | 0b00000001; // PortC0 is an output PORTC = PORTC & 0b00000000; // Lower PC0 }