embedded c concepts

Prepared By: Reetu Gupta. IT Dept. DYPCOE

Android OS OS for mobile (mobility) devices. Handheld Devices - PDA

-Smartphone's- Tablets

-Mobile Phones


PIC Embedded C Basics Variable Declaration. Loops Decision Making Micro Controller Program Imp Characteristics

Less memory for Program and Data


PIC Embedded C Basics Variable Declaration - Data type is selected based

on data usage

Data Type Size in Bits RangeInt1 1 0 /1

Unsigned int8 8 Bit But in C it is 16 bit but for Microcontroller it is 8 bit

0 to 255

Signed int8 8 -128 to +127Unsigned int16 16 0 to 65535

Signed int16 16 -32767 to 32768Unsigned int32 32 0 to 4294967296

Signed int32 32 -2147483648 to 2147483647


Floating Point Data Format for PIC Microcontroller

Exponent Sign MantissaXXXX XXXX X XXX XXXX XXXX XXXX XXXX XXXX

8 bit 1 bit 23 bits

•PIC Uses 32-bit format for floating number representation.


Embedded C Program Program to print a value on Port#include header filevoid main(){ output _X();//X– The port where u want to print assign a value -- Value is given in brackets. E.g. (25)}

#include “16F877A.h”void main(){ output _C(85);}


Embedded C Program Program to assign a value to port #include header filevoid main(){data_type variable_name;variable_name=input_X();Output_X(variable_name);

}

#include “16F877A.h”void main() { int i; // I is integer variablei=input_C(); // value given as input to port C is stored in iOutput_A(i);// And it is being printed at port C }


Embedded C Loops Variable Declaration - Data type is selected based

on data usage

Data Type Size in Bits RangeInt1 1 0 /1

Unsigned int8 8 Bit But in C it is 16 bit but for Microcontroller it is 8 bit

0 to 255

Signed int8 8 -128 to +127Unsigned int16 16 0 to 65535

Signed int16 16 -32767 to 32768Unsigned int32 32 0 to 4294967296

Signed int32 32 -2147483648 to 2147483647


MPLAB Compiler Function

Sr. No

Library Function Use of Function

1 delay_us(x) Generate delay of x microseconds2 delay_ms(x) Generate delay of x milliseconds3 output_p(x) Output the value ‘x’ on port ‘p’4 output_high(PIN_px) Set pin ‘x’ of port ‘p’ to logic 1 / High.5 output_low(PIN_px) Set pin ‘x’ of port ‘p’ to logic 0 / Low.6 input_p() Functions returns the value on port ‘p’7 Input(PIN_px) Functions returns the value of ‘x’ pin

on port ‘p’

• MPLAB has 5 ports : A,B,C,D,E• Separate Function for Each Port


Operators• Unary • Binary

Arithmetic Bitwise Logical Relational

• Assignment• Selection


Unary Operators

Sr. No

Unary Operators

Use of Function

1 Unary Minus(-) Return negative value of operator to which it is preceded. E.g x=3, y=-x, then y=-3.

2 Logical Not (!) Logical Not operation on the value obtained from the expression on right.

3 Bitwise Not ( ~ ) Bitwise Not Operation4 Increment (++) Add 1. E.g. If x=5, then x++ will make x=6.5 Decrement (--) Sub 1. E.g. If x=5, then x-- will make x=4

• Operation to be performed is given by: Operators• Data :operation will be performed : Operands• Operator require one operand : Unary Operator


Pre and Post Increment Operators

Sr. No

Unary Operators

Use of Function

1 Pre Increment X=5, y=++x. Then y=6, x=52 Post Increment X=5, y=x++. Then y=5, x=63 Pre Decrement X=5, y=--x. Then y=4, x=54 Post Increment X=5, y=x--. Then y=5, x=4

Pre : First Operation Then Assign

Post: First Assignment Then Operation

• ++ :• ++x– Preincrement • x++ Post Increment

-- :• --x– Preincrement • x-- Post Increment


C Peripheral Interface: PIC18F877• ADC : Analog to Digital Converter• PIC18F :

• A single 10-bit ADC• 8 Analog: Input Channel: Port A (6 pins) and Port E (2 pins)• Port A : RA0 to RA5 and Port E: RE1 and RE2• MPLAB function : Handling ADC of PIC18F877


C Peripheral Interface: PIC18F877Sr. No

Unary Operators Use of Function

1 setup_adc(ADC_CLK_INTERNAL)

Set ADC using Internal Clck Pluse

2 setup_adc_ports(Rpx_Analog) Initial pin ‘x’ of port ‘p’as analog input.

3 set_adc_channel(x) Selects channel x to provide input to ADC

4 read_adc() Reads the value of ADC and return it to variable on left.


C Mechatronics Applications• Driving Motors : Stepper Motor, DC Motor, Servo Motor.• Interfacing Display ( LCD or LED)

embedded c concepts

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