Tiva Lab 02: Home Control System

Figure 1: The Simulation Circuit for Home Using TM4C123GXL

Figure 1.2: The Circuit Connection on the Breadboard

Table 1: Pin Configurations:

Figure 1: The Simulation Circuit for Home Using TM4C1294XL

Figure 1.2: The Circuit Connection on the Breadboard

Table 1: Pin Configurations:

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

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

void Doorbell(void);
void RoomLightingControl(void);
void StairwallLightingControl(void);

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

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

    // Turn off LED2 here

    while (1) {
        Doorbell();
        RoomLightingControl();
        StairwallLightingControl();

        DelayMs(20);
    }
}
//------------------------------------------------------------------------------
void Doorbell()
{
    // Place your application code here

}
//------------------------------------------------------------------------------
void RoomLightingControl()
{
    // Place your application code here

}
//------------------------------------------------------------------------------
void StairwallLightingControl()
{
    // Place your application code here

}
//------------------------------------------------------------------------------
void Setup_GPIO()
{
    // 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
    // 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
}

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

#include "TM4C1294NCPDT.h"
#include "MyDefines.h"

void Doorbell(void);
void RoomLightingControl(void);
void StairwallLightingControl(void);

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

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

    // Turn off LED2 here

    while (1) {
        Doorbell();
        RoomLightingControl();
        StairwallLightingControl();

        DelayMs(20);
    }
}
//------------------------------------------------------------------------------
void Doorbell()
{
    // Place your application code here

}
//------------------------------------------------------------------------------
void RoomLightingControl()
{
    // Place your application code here

}
//------------------------------------------------------------------------------
void StairwallLightingControl()
{
    // Place your application code here

}
//------------------------------------------------------------------------------
void Setup_GPIO()
{
    // 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
}

The doorbell control circuit is very simple. When you prod the button, the circuit will be connected, and you will hear a buzzing noise. The electrical circuit for the doorbell is shown as the following Figure 3:

Figure 3: The Electrical Circuit for Doorbell

Figure 4: The Simulation Circuit for Doorbell

 

We use a microcontroller to implement the doorbell circuit. From Figure 3, we can easily understand that the doorbell is triggered only when a user presses the button, otherwise, the doorbell should be inactive. Then we convert the circuit behaviors to a flowchart, as shown in Figure 5.

Figure 5: The Flowchart for Doorbell Controller.

Implement the flowchart in the Doorbell() function. Build and download the code to the Tiva board, and test it.

Most rooms in a house will have one or more wall switches used to control lighting fixtures or electrical outlets. There have only three kinds of wall switches that are used to control light fixtures: simple single-pole (ON/OFF) switches, three-way switches, and four-way switches. A Single-Pole switch is one that just turns the light ON or OFF from one wall location.

Figure 6: Simple Room Light Control

 
Figure 7: A Single-Pole Switch Using on Light Control

Figure 8: The Electrical Circuit for Room Light Control

Figure 9: The Simulation Circuit for Room Light Control

A single-pole switch has two positions: OFF and ON. When you toggle the lever to the ON position, the switch gate snaps closed, which allows current to flow through the light. The switch will remain in the ON position until the lever is flipped to the OFF position, which opens the gateway up and interrupts the flow of power to the light. The electrical circuit is shown in Figure 8.

The switches we used in the circuit are momentary pushbutton switches. They are non-latching switches and change the state of the electrical circuit only while the switch is physically actuated. In other words, a momentary switch allows electricity to flow between its two contacts while the button is depressed. Upon releasing the button, the circuit is broken.

Therefore, to implement a room light controller, the microcontroller needs to retain the state of the light or switch, and when the user presses the button, it will then change the state of the light or switch. In the code, the current state needs to be saved as a variable.

You may think of using the same flowchart that was used in the previous experiment to control the light. In Figure 5, when the system detects the button pressed, it will turn on the light. The system will continue to check the state of the switch, and once the user releases the button, the system will detect that the switch is off and turn OFF the light.

However, the goal for today is to keep the light turned ON until the button is pressed again. By using the technique from previous experiment, customers will have to hold on to the button to turn ON the light, and can only release it when the light is not needed.

There are two solutions that can be used in this case:

1. Finite State Machine (based on behavior state)
2. Software Edge Detection (based on electrical timing)

Next, implement a control switch that is often used in stairwells as shown in Figure 12.

Figure 12: The Light Control System at the Stairwells

The stairwell lights are controlled by switches that are installed on each floor. When you want to go up/down the stairs, just press the switch to turn on the lights on the wall. After reaching the target floor,  simply press the switch on the current floor to turn off the lights.

Now, you have to design a system to support the stairwell light. Two switches control one LED, which means you can turn on the LED on one of the switches and also can use one switch to turn off the LED. The code should be similar to the previous experiment, but add one more switch to toggle the LED.

After resetting, the LED2 should be turned off. If your LED2 is on, you have to turn it off after calling Setup_GPIO() function before entering the infinite while-loop.