Tiva Lab 03: Police LED Light Bar Simulation

Objective

Develop and code an electronic setup using LEDs and a microcontroller to imitate the police LED light bar.

PoliceLights 01

Components Required

Component/Device	Description	Quantity
	220 Ω (red red brn gld / red red blk blk brn)	× 6
	Red LED	× 3
	Blue LED	× 3
	Push Button (Switch)	× 1

Circuit Diagram

Position the six LEDs on your breadboard, and pair each one with a 220-ohm resistor. These resistors ensure safe current levels for the LEDs, preventing potential damage.
Link every LED-resistor combo to a digital output terminal on the microcontroller.
Attach the push button switch to a digital input on the microcontroller, configuring the pins to function in input mode with an accompanying pull-up resistor.

Pin configurations

Device	Port.Pin	Signal Type	Module	Direction	Drive Mode

Example Firmware Code

Copy-paste the following code to your main.c file.

Example Firmware Code

EK-TM4C123GXL LaunchPad - main.c

Sample Firmware Code:


#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h>

#include "TM4C123GH6PM.h"
#include "MyDefines.h"

void DelayMs(int ms);   // Software Delay Function
void Setup_GPIO(void);

int main(void)
{
    // Place your initialization/startup code here (e.g. Setup_GPIO() )
    Setup_GPIO();

    while (1) {
        // Place your application code here

    }
}
//------------------------------------------------------------------------------
/*
Device      Port.Pins       DIR     DriveMode
LEDR0
LEDR1
LEDR2
LEDB0
LEDB1
LEDB2

Port ____
*/
              
void Setup_GPIO(void)
{
    // Configure GPIOs
    // 1. Enable Clock to the GPIO Modules (SYSCTL->RCGCGPIO |= (_PORTs);)
    SYSCTL->RCGCGPIO |= (__);
    // allow time for clock to stabilize (SYSCTL->PRGPIO & (_PORTs))
    while ((SYSCTL->PRGPIO & (__)) != (__)) {};
    // 2. Unlock GPIO only PD7, PF0 on TM4C123G; PD7, PE7 on TM4C1294 (GPIOx->LOCK = 0x4C4F434B; and GPIOx->CR = _PINs;)
    //GPIOF->LOCK = 0x4C4F434B;   // Unlock for GPIOF
    //GPIOF->CR |= _PIN0;         // Commit for PIN0
    //GPIOF->LOCK = 0;
    // 3. Set Analog Mode Select bits for each Port (GPIOx->AMSEL = _PINs; 0=digital, 1=analog)
    // 4. Set Port Control Register for each Port (GPIOx->PCTL = PMCn << _PTCL_PINn, check the PCTL table)
    // 5. Set Alternate Function Select bits for each Port (GPIOx->AFSEL = _PINs; 0=regular I/O, 1=PCTL peripheral)
    // 6. Set Output pins for each Port (Direction of the Pins: GPIOx->DIR = _PINs; 0=input, 1=output)

    // 7. Set PUR bits (internal Pull-Up Resistor), PDR (Pull-Down Resistor), ODR (Open Drain) for each Port (0: disable, 1=enable)
    // 8. Set Digital ENable register on all port.pins (GPIOx->DEN = _PINs; 0=disable, 1=enable)

}
//------------------------------------------------------------------------------
// Delay ms milliseconds (4167:50MHz TM4C123G CPU, 1605:16MHz TM4C123G CPU Clock)
void DelayMs(int ms)
{
    volatile int i, j;
    for (i = 0; i < ms; i++)
        for (j = 0; j < 4167; j++) {} // Do nothing for 1ms
}

EK-TM4C1294XL LaunchPad - main.c

Sample Firmware Code:

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h>
 
#include "TM4C1294NCPDT.h"
#include "MyDefines.h"
 
void DelayMs(int ms);   // Software Delay Function
void Setup_GPIO(void);
 
int main(void)
{
    // Place your initialization/startup code here (e.g. Setup_GPIO() )
    Setup_GPIO();
    while (1) {
        // Place your application code here

    }
}
//------------------------------------------------------------------------------
/*
Device      Port.Pins       DIR     DriveMode
LEDR0
LEDR1
LEDR2
LEDB0
LEDB1
LEDB2

Port ____
*/
void Setup_GPIO(void)
{
    // Configure GPIOs
    // 1. Enable Clock to the GPIO Modules (SYSCTL->RCGCGPIO |= (_PORTs);)
    SYSCTL->RCGCGPIO |= (__);
    // allow time for clock to stabilize (SYSCTL->PRGPIO & (_PORTs))
    while ((SYSCTL->PRGPIO & (__)) != (__)) {};
    // 2. Unlock GPIO only PD7, PF0 on TM4C123G; PD7, PE7 on TM4C1294 (GPIOx->LOCK = 0x4C4F434B; and GPIOx->CR = _PINs;)
    // 3. Set Analog Mode Select bits for each Port (GPIOx->AMSEL = _PINs; 0=digital, 1=analog)
    // 4. Set Port Control Register for each Port (GPIOx->PCTL = PMCn << _PTCL_PINn, check the PCTL table)
    // 5. Set Alternate Function Select bits for each Port (GPIOx->AFSEL = _PINs; 0=regular I/O, 1=PCTL peripheral)
    // 6. Set Output pins for each Port (Direction of the Pins: GPIOx->DIR = _PINs; 0=input, 1=output)
 
    // 7. Set PUR bits (internal Pull-Up Resistor), PDR (Pull-Down Resistor), ODR (Open Drain) for each Port (0: disable, 1=enable)
    // 8. Set Digital ENable register on all port.pins (GPIOx->DEN = _PINs; 0=disable, 1=enable)
 
}
//------------------------------------------------------------------------------
// Delay ms milliseconds (1605: 16MHz TM4C1294 CPU Clock)
void DelayMs(int ms)
{
    volatile int i, j;
    for (i = 0; i < ms; i++)
        for (j = 0; j < 1605; j++) {}   // // Do nothing for 1ms
}

Implementation

You are tasked with crafting a minimum of three distinctive police LED light sequences. Consider utilizing a struct to structure the LED sequence as demonstrated::

typedef struct LEDPAT{
    uint8_t leds;
    uint8_t duration;
} LEDPAT;

Structure three pattern arrays as shown:

LEDPAT Pattern1[] = {
                    { , }, // First item  
                    ...
};
LEDPAT Pattern2[] = {
                    { , }, // First item  
                    ...
};
LEDPAT Pattern3[] = {
                    { , }, // First item  
                    ...
};

Within the "main()" function, iterate through your pattern arrays. Illuminate the LEDs as directed by the "leds" parameter in the pattern, and introduce a pause (in milliseconds) as dictated by the "duration" parameter. When the switch (SW1) is activated, shift to the subsequent pattern. Employ software edge-detection techniques to ascertain SW1's state.

Note: Feel free to modify LED sequences and their respective durations to suit your preferences.