Microchip 8 bit Microcontroller Assembly Language Programming

Duration: 5 Days

Course Background

A knowledge of assembly language programming is a key skill for small embedded systems application developers. Not only does an understanding of the microcontroller instruction set help with debugging, it can be used to optimise code in resource constrained systems. It is also an important skill to have when implementing applications that are a mix of assembler and C code and when implementing low level device drivers. The Microchip 8 bit Microcontroller family is characterised by the fact that as one moves from the low end microcontrollers such as the PIC10, PIC12 on to the PIC16 and PIC18 families so more instructions are added to the instruction set. Also the details of the memory architecture and interrupt handling change. Thus the PIC18 has two interrupt priority levels whereas the PIC16 has just one level of interrupt.

This course will cover the entire range of 8 bit microcontrollers. It will also cover techniques for modular programming in assembler and the structured use of macros. It should also be of use to those teaching or developing computer science courses who will be delivering a module on microprocessor architectures, instruction sets and basic programming at the level of instruction sets.

Laboratory Workshops

Program object code into a target PIC16 / PIC18 microcontroller using MPLABX and ICD3
Create, build and debug new assembly language projects using MPLABX and ICD3
Use the MPLAB X Simulator to simulate and debug code prior to programming it into a target device
Understand the components of an assembly source file
Setting the PIC16 and PIC18 configuration options appropriately for the target system
Use digital I/O ports to interact with the outside world
Manipulating data memory using direct and indirect addressing
Create time delays using software loops and hardware timers
Take advantage of interrupts to handle events in the background
Jump and call routines across pages in program memory
Use of PC-relative addressing to implement look-up tables
Implement robust design techniques to protect against malfunctions

Course Prerequisites and Target Audience

Basic knowledge of programming and working with PC tools is assumed. Attendees are also expected to have a working knowledge of number systems decimal, octal, hexadecimal and binary and basic logic operations such as AND, OR, Exclusive OR and NOT. An appreciation of basic approaches to structured programming would also be helpful.

Course Outline

Microchip Overview

Market profile
product range
key advantages and support network

Overview of Development Tools

Microchip development software: MPLABX and associated tools
Microchip In-Circuit Debugger (ICD3) and In-Circuit Emulator (ICE) hardware
Device programmers, and the design option of In-Circuit Serial Programming (ICSP)
Demonstration boards and kits
Third-party development tools

The PIC16 and PIC18 Architectures and Instruction Sets

The difference between a microcntroller and a microprocessor
Harvard versus Von Neumann architecture
Organisation of program and data memory
Op-codes and addressing modes: immediate, direct and indirect
On-chip peripherals and interrupts
Classes of operations performed by op-codes
The System Clock
Resets and Reset circuits
Differences in instruction sets and memory architecture between PIC16 and PIC18 microcontrollers

The PIC10 and PIC12 Architectures and Instruction Sets

The need for small, cheap and simple microcontrollers
Overview of the PIC10 and PIC12 families and their uses
The PIC10 and PIC12 instruction sets viewed as subsets of the PIC18 instruction set

The PIC 8 bit processor architecture and Instruction Set Details

Understanding microcontroller pinouts and schematic diagrams
The PIC 8 bit Microcontroller Instruction Sets

Data Transfer Instructions
Arithmetic Logic Instructions
Bit-oriented Instructions
Program Control Instructions
Other Instructions

Understanding PIC 8 bit Microcontroller Addressing Modes

Direct addressing
Register Direct Addressing
Register Indirect Addressing
Indexed Addressing

Special Function Registers and Ports

The need for Special Function Registers
STATUS Register
OPTION_REG Register
INTCON Register
PIE Register
PIR Register
PCON Register
PCL and PCLATH Registers
TRIS Registers
PORT Registers
ANSEL and ANSELH Registers
Overview of Peripheral Associated Special Function Registers

Designing and implementing programs and applications

Requirements analysis
Describing algorithms using pseudo code (structured English)
Describing algorithms using flow charts
Basic template for a PIC16/PIC18 assembler language application
Brief Introduction to Structured Analysis and Design using Ward-Mellor / Hatley Pirbhai / Jackson methodologies

Context Diagram
Flow diagrams
Control diagrams
Finite State Machines
Function mini-specs and pseudo code

Macros

Macros as pattern substitution
Macros with parameters
Macros and subroutines compared
Macros with parameters
Common Macro based patterns and idioms

Interrupts

The interrupt handling architecture of the PIC16 and PIC18
Interrupts and Event Driven Systems
Synchronous vs. Asynchronous Event Handling
Template for implementing an interrupt handler
Effective use of high and low level interrupt priorities in the PIC18

Digital Inputs and Outputs

Programming Digital Outputs
Programming Digital Inputs
Using Polling to detect input changes
Using Edge Triggered Interrupts to detect input changes
Debouncing
Programming a matrix keypad

Timers

How timers work
Timeout events and timeout handlers
Capture Compare
Pulse width modulation
Timers for generating periodic events
Timers and multi-tasking

Analog Inputs

Understanding Analog to Digital Conversion (ADC)
ADC architectures
Program templates for working with analog inputs
Foundations of signal processing
Use analog inputs to control and monitor

Serial buses and Protocols

RS232
I2C
SPI