Tiva Lab 05: Home Control System

#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
    GPIOx->DATA _________;

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

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

}
//------------------------------------------------------------------------------
void RoomLightingControl()
{
    static bool preSw2 = ____;
    bool        curSw2;

    // Place your application code here

}
//------------------------------------------------------------------------------
void StairwallLightingControl()
{
    static bool preSw3 = ____;
    bool        curSw3;
    static bool preSw4 = ____;
    bool        curSw4;

    // Place your application code here

}
//------------------------------------------------------------------------------
/*
Device      Port.Pins       DIR     DriveMode
SW1
SW2
SW3
SW4
Buzzer
LED1
LED2

Port ____
*/

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;)
    // 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;)
    // 6. Set the output pins for each port only (Direction of the Pins: GPIOx->DIR = _PINs;)

    // 7. Set PUR bits (internal Pull-Up Resistor), PDR (Pull-Down Resistor), ODR (Open Drain) for each Port

    // 8. Set Digital ENable register on all digital port.pins (GPIOx->DEN = _PINs;)

}
//------------------------------------------------------------------------------
// 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
    GPIOx->DATA _________;

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

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

}
//------------------------------------------------------------------------------
void RoomLightingControl()
{
    static bool preSw2 = ____;
    bool        curSw2;

    // Place your application code here

}
//------------------------------------------------------------------------------
void StairwallLightingControl()
{
    static bool preSw3 = ____;
    bool        curSw3;
    static bool preSw4 = ____;
    bool        curSw4;

    // Place your application code here

}
//------------------------------------------------------------------------------
/*
Device      Port.Pins       DIR     DriveMode
SW1
SW2
SW3
SW4
Buzzer
LED1
LED2

Port ____
*/

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;)
    // 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;)
    // 6. Set the output pins for each port only (Direction of the Pins: GPIOx->DIR = _PINs;)

    // 7. Set PUR bits (internal Pull-Up Resistor), PDR (Pull-Down Resistor), ODR (Open Drain) for each Port

    // 8. Set Digital ENable register on all digital port.pins (GPIOx->DEN = _PINs;)

}
//------------------------------------------------------------------------------
// 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
}
//------------------------------------------------------------------------------

Software Edge Detection

Let us analyze the system's behavior according to the timing sequence.

In the circuit shown in Figure 9, SW2 is connected to the microcontroller's input pin as a positive-logic input. This means that when the user presses the switch, the input pin is connected to the power supply, so its logic value is 1. If the user releases the switch, the switch disconnects; the input pin connects to ground through the (internal) pull-down resistor, and the input pin's logic value becomes 0. The timing diagram for the SW2 is shown in Figure 11.

From the Moore state diagram (Figure 10), we can observe that the LED output changes each time the user presses the switch. If the user continues to hold or release the switch, the LED will not change. In the timing diagram, you can see that when the user presses SW2, the logic value of the input pin changes from 0 to 1; the point at which this change occurs is called the rising edge. We found that the LED changes only on the falling edge of the input pin. Hence, the microcontroller just needs to detect the rising edge on the input pin and then change the output value.

A simple if statement method is convenient for implementing software edge detection. In the code, you have to create two local variables:

• One is a static local Boolean variable (ex. static bool preSW2) that holds the last state value. This variable is also assigned an initial value equal to the logic value of the input pin when the switch is inactive.
• Another local Boolean variable without an initial value (ex. bool curSW2) is used to save the current state of the input pin.

The following steps show how to detect the falling edge:

1. Read the current state value of the input pin that connects to the SW2 and save that value to the curSW2 variable.
2. Check the previous and current state variables:
   If the previous state preSW2 is logic 0 (which means the SW2 has been released before) and the current state curSW2 is logic 1 (just pressing the SW2), it means that a rising edge occurred on the pin that is connected to the SW2, and then changes the LED state
3. Stores the current state value to the previous state variable (preSW2 = curSW2).

BEGIN

    READ SW2_CURRENT_STATE INTO curSW2

    IF preSW2 = LOW AND curSW2 = HIGH THEN
        TOGGLE LED
    ENDIF

    preSW2 ← curSW2

END

Comment out all the previous code in the RoomLightingControl() function and implement the software edge detection (simple if statement method). Build and download the code to the Tiva board, then show the result to the instructor.

You can use the toggle function with edge detection to control the light. The pseudocode is as follows:

Using Software Edge Detection

BEGIN

    READ SW3_CURRENT_STATE
    READ SW4_CURRENT_STATE

    IF SW3_PREVIOUS_STATE = HIGH AND SW3_CURRENT_STATE = LOW THEN
        TOGGLE LED2
    ENDIF

    IF SW4_PREVIOUS_STATE = HIGH AND SW4_CURRENT_STATE = LOW THEN
        TOGGLE LED2
    ENDIF

    SW3_PREVIOUS_STATE ← SW3_CURRENT_STATE
    SW4_PREVIOUS_STATE ← SW4_CURRENT_STATE

END