what is the serial communication?

what is the serial communication?

what is the serial communication? Unlike parallel communication, where several bits are send at one time, Serial Communication is a process of transmitting data bit by bit. In this tutorial, you will learn how to serially communicate a PC or any other device with a PIC microcontroller. You will also study the use of a communication component – UART (Universal Asynchronous Receiver Transmitter) present within the microcontroller.

Serial vs Parallel Transfer:

PCs  move  information  two way:  sequential  and parallel.  In  sequential  Communication,  just  a  solitary  wire  is  needed  to  move  n  pieces  of  information  or  a  couple  of  wires  for  prepared  and  recognize  signals  while  in  equal correspondence,  and  wires  are  needed  to  move  n  pieces  of  information.  Sequential  mode  is  utilized  to  move  information  to  more  noteworthy  distances  and  equal  just  works  for  brief  distances.  Since  more  equipment  is  needed  in  equal  correspondence  mode,  thus,  sequential  correspondence  is  liked.  In  information  Transmission,  if  information  can  both  be  communicated and  gotten,  it  is  a  duplex  transmission.  Interestingly,  a  simplex  transmission  just  sends  information  from  one  gadget  to  the  next,  for  example,  from  PC  to  printer.  Duplex  Transmission  can  be  Half  or  Full  duplex  contingent  on  if  the  information  move  is  concurrent.  On  the  off  chance  that information  is  communicated  each  path in  turn,  it  is  half  duplex. and  the  event  that  information  can  go  the  two  different  ways  simultaneously,  it  is  Full  duplex.  PIC  microcontroller  has  a  full-duplex,  sequential  method  of  Communication.  Half  and  Full-Duplex  Transmission.

What is SPI Communication Protocol?

The  term  SPI stands  for  “Sequential  Peripheral  Interface”.  It  is  a  typical  correspondence  convention  that  is  utilized  to  send  information  between  two  microcontrollers  or  to  peruse/compose  information  from  a  sensor  to  a  microcontroller.  It  is  likewise  used  to  speak  with  SD  cards,  shift  registers,  Display  regulators  and  substantially  more.

How SPI Protocol Works?

The  SPI  correspondence  is  coordinated  correspondence,  which  means  it  works  with  the  assistance  of  a  clock  signal  which  is  divided  among  the  two  gadgets  that  are  trading  the information.  Additionally  it  a  full-duplex  correspondence  since  it  can  send  and  get  information  utilizing  a  different  transport.  The  SPI  correspondence  requires  5  wires  to  work.  

The  five  wires  needed  for  the  correspondence  are  SCK  (Serial  Clock),  MOSI  (Master  Out  Slave  in),  MISO  (Master  in  Slave  Out)  and  SS  (Slave  Select).  The  SPI  correspondence  consistently  takes  puts  just  between  an  expert  and  slave.  An  expert  can  have  various  slaves  associated  with  it.  The  expert  is  answerable  for  creating  the  clock  beat  and  the  equivalent  is  imparted  to  all  slaves.  Additionally  everything  interchanges  can  be  started  exclusively  by  the  expert.  


The  SCK  pin  (a.k.a  SCL-sequential  clock)  shares  the  clock  signal  produces  by  the  expert  with  the  slaves.  The  MOSI  pin  (a.k.a  SDA   Serial  Data  Out)  is  utilized  to  send  the  information  from  the  expert  to  the  ointment.  The  MISO  pin  (a.k.a  SDI   Serial  Data  In)  is  utilized  to  get  the  information  from  the  treatment  to  the  expert.  You  can  likewise  follow  the  bolt  mark  in  the  above  figure  to  comprehend  the  development  of  information/signal.  At  last,  the  SS  pin  (a.k.a  CS  –  Chip  select)  is  utilized  when  there  are  more  than  one  slave  modules  associated  with  the  expert.  This  in  can  be  utilized  to  choose  the  necessary  slave.

Difference between I2C and SPI Communication

We  have  as  of  now  educated   I2C  correspondence  with  PIC  thus  we  should  be  comfortable  with  how  I2C  functions  and  where  we  can  utilize  them  like  I2C  can  be  utilized  to  interface  RTC  module.  In  any  case,  presently,  for  what  reason  do  we  need  SPI  convention  when  we  as  of  now  have  I2C.  The  explanation  is  both  I2C  and  SPI  interchanges  are  benefits  in  its  own  particular  manners  and  subsequently  is  application  explicit.  

To  a  degree  the  I2C  correspondence  can  be  considered  to  enjoy  some  upper  hands  over  SPI  correspondence  on  the  grounds  that  I2C  utilizes  less  number  of  pin  and  it  gets  convenient  when  there  are  countless  slaves  associated  with  the  transport.  However,  the  disadvantage  of  I2C  is  that  it  has  a  similar  transport  for  sending  and  accepting  information  and  thus  it  is  relatively  sluggish.  So  it’s  absolutely  founded  on  application  to  choose  SPI  and  I2C  convention  for  your  task

UART Communication using PIC microcontroller

In  this  instructional  exercise  we  figure  out  how  to  Enable  UART  correspondence  with  PIC  Microcontroller  and  how  to  move  information  to  and  from  your  Computer.  Up  until  now,  we  have  covered  all  essential  modules  like  ADC,  Timers,  PWM  and  furthermore  have  figured  out  how  to  interface  LCDs  and  7-Segment  shows.  Presently,  we  will  furnish  our  self  with  another  specialized  apparatus  called  UART  which  generally  utilized  in  the  majority  of  the Microcontroller  projects.  Check  here  our  total  PIC  Microcontroller  Tutorials  utilizing  MPLAB  and  XC8.  

Here  we  have  utilized  PIC16F877A  MCU,  it  has  a  module  called  “Addressable  Universal  Synchronous  Asynchronous  Receiver  and  Transmitter”  instantly  known  as  USART.  USART  is  a  two  wire  correspondence  framework  in  which  the  information  stream  sequentially.  USART  is  additionally  a  full-duplex  correspondence,  implies  you  can  send  and  get  information  simultaneously  which  can  be  utilized  to  speak  with  fringe  gadgets,  like  CRT  terminals  and  PCs.

UART communication
UART communication

The  USART  can  be  configured  in  the  following  modes:

  • Asynchronous (full-duplex)
  • Synchronous –  Master  (half-duplex)
  • Synchronous –  Slave  (half-duplex)

There  are  likewise  two  distinct  modes  to  be  specific  the  8-digit  and  9-cycle  mode,  in  this  instructional  exercise  we  will  design  the  USART  module  to  work  in  Asynchronous  mode  with

8-bit  correspondence  framework,  since  it  is  the  most  utilized  kind  of  correspondence.  As  it  is  nonconcurrent  it  doesn’t  have  to  convey  clock  message  alongside  the  information  signals.  UART  utilizes  two  information  lines  for  sending i(TX)  and  accepting  (Rx)  information.  The  ground  of  the  two  gadgets  ought  to  likewise  be  made  normal.  This  sort  of  correspondence  doesn’t  share  a  typical  clock  subsequently  a  shared  belief  is  vital  for  the  framework  to  work.  

Toward  the  finish  of  this  instructional  exercise  you  will  be  capable  build  up  a  correspondence  (UART)  between  your  PC  and  your  PIC  Microcontroller  and  flip  a  LED  on  the  PIC  board  from  your  PC.  The  situation  with  the  LED  will  be  shipped  off  your  PC  from  the  PIC  MCU.  We  will  test  the  yield  utilizing  Hyper  Terminal  in  PC.  Definite  Video  is  additionally  given  toward  the  finish  of  this  instructional  exercise.


  • PIC16F877A Perf  Board
  • RS232 to  USB  converter  Module
  • Computer
  • PICkit 3  Programmer



  • HyperTerminal

A  RS232  to  USB  converter  is  required  to  convert  the  serial  data  into  computer  readable  form.  There  are  ways  to  design  your  own  circuit  instead  of  buying  your  own  module  but  they  are  not  reliable  as  they  are  subjected  noise.  The  one  which  we  are  using  is  shown  below

Note: Each RS232 to USB converter would require a special driver to be installed; most of them should get installed automatically as soon as you plug in the device. But, if it doesn’t relax!!! Use the comment section and I will help you out.

Also read here



Briefly write about all pins of LCD for connecting with the PIC microcontroller



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