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Push Buttons - Embedded System Design - Lecture Slides, Slides of Computer Science

These are the Lecture Slides of Embedded System Design which includes Hardware Design, Elevator Controller, Simple Elevator Controller, Try Capturing, Unit Control, Request Resolver, Sequential Program Model, Partial English Description, System Interface etc. Key important points are: Push Buttons, Dragon Board, Corresponding, Released, Using Switches, Same Bits, Level Sensitive Data, Position, Corresponding, Activity Level

Typology: Slides

2012/2013

Uploaded on 03/22/2013

dhritiman
dhritiman 🇮🇳

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Using push buttons and switches
1
Push buttons SW2 to SW5 on the Dragon Board are connected to bits 3 to 0 of
PortH
When button is pushed, a corresponding bit of Port H is reset. What activity
level?
Can be enabled/disabled:
SW_enable();
Can be checked with C function calls:
SW1_dip(); //returns 8-bit reading of SW1-SW5. Non-blocking
SW2_down(); // true if SW2 is down
SW2_up(); //true if SW2 is up.
Use
while ((PTH & 0x01)==0) //to check if the SW5 is being pressed
{
//…SW5 still pressed
}
//SW5 released
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Using push buttons and switches

• Push buttons SW2 to SW5 on the Dragon Board are connected to bits 3 to 0 of

PortH

• When button is pushed, a corresponding bit of Port H is reset. What activity

level?

• Can be enabled/disabled:

• SW_enable();

• Can be checked with C function calls:

• SW1_dip(); //returns 8-bit reading of SW1-SW5. Non-blocking

• SW2_down(); // true if SW2 is down

• SW2_up(); //true if SW2 is up.

• Use

while ((PTH & 0x01)==0) //to check if the SW5 is being pressed

//…SW5 still pressed

//SW5 released

Using switches

• There are also 8 DIP switches (sliders) on the Dragon

board.

• The rightmost 4 switches share the same bits of portH with

push buttons.

• These switches are intended for use as level-sensitive data

inputs to a circuit.

• When a switch is in the ON position (away from LCD) it

provides a 0 bit on corresponding PORT H bit.

• What activity level?

• Use:

• DDRH=0x00; //Port H inputs

• leds_on(~PTH);

Using LEDs

• The Dragon board provides 8 red LEDs.

• You can use C function calls to set/reset LEDs

• led_on(int b); //Sets bit b of PORTB High, or on

• led_off(int b); //Sets bit b of PORTB Low, or off

• leds_on(int h); //Sets bits of all 8 leds according to hexadecimal value h

Seven Segment Display

• The Dragon Board has four 7-segment

displays. These displays are arranged with

the intent of displaying numbers of medium

sizes.

• Must be enabled/disabled since using same

port B of LEDs:

• seg7_enable();

• seg7_disable();

• Applying a high logic level to a segment

causes it to light up, and applying a low logic

level turns it off.

• seg7_on(int s, int b); //turns on segment

s on 7SEG digit b

• What will be the hexadecimal digit coding

(assume 0 segment is least significant)? [

coded as 0x6F]

• Use seg7dec(int s, int b); //display

hexadecimal value of i on 7SEG digit b Docsity.com

Using LCD

• Use:

char * msg;

msg=“Dragon12-Plus”;

lcd_init(); //set configurations

set_lcd_addr(0x01);//for first line

type_lcd(msg);

set_lcd_addr(0x45); //for second line

Next

• 3/03/2010 Lab1: CodeWarrior Tutorial with examples

• 3/05/2010 Lab2: Dealing with individual LEDs and Delay via

PLL

• 03/08/2010 - 03/12/2010 Spring break, NO classes

• 25 03/15/2010 Lab3: Push-buttons, Dip Switches, and

Keypad

• 03/17/2010 Lab 4: LCD and Serial Communication Interface

(SCI)/UART

• Answer questions and submit code in the lab reports. Show

instructor when finished. Lab reports are due a week after

each assignment (skipping spring break).