Micro-controllers (PIC) based Application Development
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The document provides an overview of microcontrollers, including their architectures, comparisons to microprocessors, and guidelines for selecting them. It covers system development concepts, host and target environments, as well as a variety of interfaces like digital keypads, interrupts, and timers. Additionally, it discusses various components and their applications, such as analog inputs, displays, and data storage, for creating embedded systems.
Micro-controllers (PIC) based Application Development
- 2. Microcontrollers ● Introduction ● System Development Concept (Low Level) ● Understanding Target ● Work Environment and Development Guidelines ● Lets Roll Out on Interfaces
- 3. Introduction
- 4. Introduction ● What is a Microcontroller ● General Architectures ● µP vs µC ● Choosing a Microcontroller
- 5. Introduction What is a Microcontroller? ● An Integrated Circuit which is capable of being programmed to preform a specific task. ● The design normally has restrictions on its – Memory Size – I/O Capabilities – Peripheral Functions etc.,
- 6. Introduction General Architectures ● Shared signals and memory for code and data ● Physically separate signals and storage for code and data
- 7. Introduction µP vs µC - Microprocessors ● All separate components ● More flexible ● More design complexity
- 8. Introduction µP vs µC - Microcontroller ● All components in single chip ● Less flexible ● Less design complexity
- 9. Introduction Choosing a Microcontroller ● Applications ● Performance ● Price ● Availability ● Availability of Tools ● Special Capabilities
- 10. System Development Concepts (Low Level)
- 11. System Development Concept ● Host and Target ● Host Tools
- 12. System Development Concepts Host and Target ● Host: A system which is used to develop the target. ● Target: A system which is being developed for specific application.
- 13. System Development Concepts Host Tools ● Software – Cross Compiler : PICC (Lite Version) – Code Down Loader : usbpicprog ● Hardware – usbpicprog
- 14. Understanding Target - EmxPICM02
- 15. Understanding Target ● EmxPICM02 Architecture ● EmxPICM02 Development Board ● Understanding the Target Controller
- 17. Understanding Target EmxPICM02 Development Board ● PIC16F887 ● GLCD ● CLCD ● SSD ● LEDs ● Analog Keypad ● Matrix Keypad ● Digital Keypad ● RS232 ● RS485 ● LIN ● SPI - EEPROM ● I2C - DS1338 ● Temperature Sensor ● I/O Extensions ● USB (PIC18F)
- 19. Understanding Target Controller PIC16F887 ● Architecture ● Program Memory ● Data Memory ● Pin Diagram ● Clocking ● I/O Config
- 20. Understanding Target Controller PIC16F887 Architecture
- 21. Understanding Target Controller PIC16F887 Program Memory
- 22. Understanding Target Controller PIC16F887 Data Memory
- 23. Understanding Target Controller PIC16F887 Pin Diagram
- 24. Understanding Target Controller PIC16F887 Clocking
- 25. Understanding Target Controller PIC16F887 I/O Config
- 26. Work Environment and Development Guidelines
- 27. Work Environment and Development Guidelines ● Workspace Creation ● Code Structure ● Code Template ● Code Dump Creation
- 29. Code Structure
- 30. Code Template #ifndef MAIN_H #define MAIN_H #include <htc.h> #endif #include “main.h” void init_config(void) { /* Initilization Code */ } void main(void) { init_config(); while (1) { /* Application Code */ } } __CONFIG(DEBUGDIS & LVPDIS & FCMDIS & IESODIS & BORDIS & DUNPROTECT & UNPROTECT & MCLREN & PWRTDIS & WDTDIS & HS ); __CONFIG(WP0 & BORV21);
- 31. Code Dump Creation ● Compilation using picc would be $ <path>/picc --chip=16f887 main.c ● Hex code dumping $ <path>/usbpicprog -p=16F887 -w -e -f pic16f887.hex
- 32. Lets Roll Out on Interfaces
- 33. Lets Roll Out on Interfaces ● LEDs ● Digital Keypad ● Interrupts ● Timers ● Clock I/O ● Analog Inputs ● SSDs ● CLCD ● Matrix Keypad ● Analog Keypad ● Data Storage
- 35. LEDs Introduction ● Simplest device used in most on the embedded applications as feedback ● Works just like diodes ● Low energy consumptions, longer life, smaller size, faster switching make it usable in wide application fields like – Home lighting, – Remote Controls, Surveillance, – Displays and many more!!
- 36. LEDs Example ● Which side will work?
- 37. LEDs Example ON ● Oops :( wrong choice. Can you explain why?
- 38. LEDs Example – Correct Choice :) ● Ooh :) looks like you know the funda.
- 40. Digital Keypad
- 41. Digital Keypad ● Introduction ● Interfacing ● Input Detection ● Bouncing Effect ● Circuit on Board
- 42. Digital Keypad Introduction ● Provides simple and cheap interface ● Comes in different shapes and sizes ● Preferable if the no of user inputs are less ● Mostly based on tactile switches ● Some common application of tactile keys are – HMI – Mobile Phones – Computer Mouse etc,.
- 43. Digital Keypad Tactile Switches Interfacing ● Considering the below design what will be input to the controller if the switch is pressed?
- 44. Digital Keypad Tactile Switches Interfacing ● Will this solve the problem which may arise in the design mentioned in previous slide?
- 45. Digital Keypad Tactile Switches Interfacing ● Now will this solve the problem which may arise in the design mentioned in previous slides?
- 46. Digital Keypad Tactile Switches Interfacing ● What would you call the this design. Is there any potential problem?
- 47. Digital Keypad Tactile Switches Interfacing
- 50. Digital Keypad Circuit on Board
- 51. Interrupts
- 52. Interrupts ● Basic Concepts ● Interrupt Source ● Interrupt Classification ● Interrupt Handling
- 53. ● An interrupt is a communication process set up in a microprocessor or microcontroller in which: – An internal or external device requests the MPU to stop the processing – The MPU acknowledges the request – Attends to the request – Goes back to processing where it was interrupted ● Polling Interrupts Basic Concepts
- 54. ● Loss of Events ● Response ● Power Management Interrupts Interrupt vs Polling
- 58. Interrupt Service Routine (ISR) ● Similar to a subroutine ● Attends to the request of an interrupting source – Clears the interrupt flag – Should save register contents that may be affected by the code in the ISR – Must be terminated with the instruction RETFIE ● When an interrupt occurs, the MPU: – Completes the instruction being executed – Disables global interrupt enable – Places the address from the program counter on the stack ● Return from interrupt
- 59. Interrupt Service Routine (ISR) ● What / What Not
- 60. Interrupt Latency ● Latency is determined by: – Instruction time (how long is the longest) – How much of the context must be saved – How much of the context must be restored – The effort to implement priority scheme – Time spend executing protected code
- 61. bit glow_led; void interrupt external_pin(void) { if (INTFLAG) { glow_led = 1; INTFLAG = 0; } } static void init_config(void) { init_external_interrupt(); } Interrupts External Interrupt - Example void main(void) { init_config(); while (1) { while (!glow_led) { if (SWITCH == 1) { glow_led = 1; } _asm; NOP; NOP; NOP; _endasm } if (glow_led) { LED = 0; } } }
- 62. Timers
- 63. Timers Introduction ● Resolution Register Width ● Tick Up Count or Down Count ● Quantum System Clock settings ● Scaling Pre or Post ● Modes ● Counter ● PWM or Pulse Generator ● PW or PP Measurement etc., ● Examples
- 64. Timers Example ● Requirement – 5 pulses of 8 µsecs ● Resolution – 8 Bit ● Quantum – 1 µsecs ● General
- 65. Timers Example
- 66. Clock I/O
- 67. Clock I/O Introduction ● Most peripheral devices depends on Clocking ● Controllers have to generate clock to communicate with the peripherals ● Some of the Controllers internal peripherals work on external clocking provided at it pins
- 68. Clock I/O Introduction ● The activity on the devices could be on – Edges – Levels
- 69. Clock I/O PWM ● Sometimes called as PDM (Pulse Duration Modulation) ● A technique used to vary the active time vs inactive time in a fixed period. ● Mostly used to control the average voltage of the Load connected. ● Used in wide applications like Motor Controls, Lamp Dimmers, Audio, Power Controls and many more..
- 70. Clock I/O PWM
- 71. Analog Inputs
- 72. Analog Inputs Introduction ● Very important peripheral in embedded systems for real time activities ● Multiplexed with normal GPIO ● Comes with different resolutions
- 75. SSD Introduction ● Array of LEDs connected internally ● Possible configurations are common cathode and common anode ● Very good line of sight ● Used in many applications
- 76. SSD Introduction Segment Data – 10100100 & Control Line - C2 Segment Data – 10010010 & Control Line - C3 Let's assume that we are using common anode dis Data map - hgfedcba Circuit
- 77. SSD Example Segment Data – 10100100 & Control Line - C2
- 78. SSD Example Segment Data – 10010010 & Control Line - C3
- 79. SSD Example
- 80. SSD Example
- 81. SSD Example
- 82. SSD Example
- 84. Character Liquid Crystal Display
- 85. CLCD Introduction ● Most commonly used display ASCII characters ● Some customization in symbols possible ● Communication Modes – 8 Bit Mode – 4 Bit Mode
- 87. Matrix Keypad
- 88. Matrix Keypad Introduction ● Used when the more number of user inputs is required and still want to save the some controller I/O lines ● Uses rows and columns concept ● Most commonly used in Telephonic, Calculators, Digital lockers and many more applications
- 90. Analog Keypad
- 91. ● Used when the more number of user inputs is required and still want to save the some controller I/O lines ● Uses a single controller I/O ● Uses voltage divider concept ● Less precise when more number of switches added Analog Inputs Introduction
- 93. Data Storage
- 94. ● Mostly used in every Embedded System ● The size and component (memory) of storage depends upon the requirements ● Modern controllers has built in data storage – EEPROM – Data Flash etc. Data Storage Introduction
- 95. Thank You