Microcontrollers and Amateur Radio
– a Club Project
Dave Green VE3TLY
QCWA Nov. 18 2008
Dave Green VE3TLY
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Acknowledgements
• Mike Kelly, VE3FFK
• David Conn, VE3KL
QCWA Nov. 18 2008
Dave Green VE3TLY
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Recent Club Projects
• 2007: ‘Smart’ Battery charger kit (Mike Kelly VE3FFK)
• 2008: Microcontroller (VE3KL, VE3FFK, VE3TLY)
– Pervasive technology,
– ‘New’ technology for many of us.
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My Reservations
• Complex technology:
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Digital hardware,
Digital systems,
Processor architectures,
Programming concepts,
Programming languages,
Software development tools,
Debugging tools.
• Club members with diverse technical backgrounds.
• Resolved by selection of appropriate technology.
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Talk Overview
• Concepts:
– Processors, Microprocessors, Microcomputers and Microcontrollers,
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Overview of PICAXE Microcontroller,
PICAXE vs. PIC,
The OARC Project,
Examples of amateur radio applications of microcontrollers.
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Concept of a Modern Digital
Stored Program Computer
Instr0
Control Unit
Instr1
Instr2
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Processing Element
InstrK
System Memory
(Program and Data)
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Microprocessor
Register Array
Arithmetic
Logic Unit
(ALU)
Control Unit
Central Processing Unit (CPU)
Data Bus
Address Bus
Control Bus
System Memory
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Microcomputer
• Board level microcomputer
• Single chip microcomputer
Microprocessor
Bus
Memory
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Input/Output
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Microcontroller
• A single chip microcomputer optimized for control
applications,
• Rich Input/Output connectivity to access:
– Switches,
– Sensors,
– Motors,
– Displays,
– Etc.
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The PICAXE used by the OARC
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Examples of Microcontroller
Applications
• Automotive:
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Engine management
Automatic transmission
Anti-lock braking
Cruise control
Dashboard Instrumentation
• Kitchen appliances,
• Power tools,
• Amateur radio gear:
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Transceivers,
Keyers,
Autotuners,
Instrumentation, antenna analyzers etc.
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PIC16F886 Microcontroller
• PIC: Programmable Intelligent Controller
• Microchip Technology Inc., (AZ)
– www.microchip.com
• 8-bit CMOS processor.
• 35 instructions – single cycle execution (RISC).
• Non-volatile memory:
– Flash program memory (8K x 14)
– EEPROM data memory (256 x 8).
• Volatile memory
– RAM data memory (368 x 8).
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Programming a PIC
C Source File
Assembly
Language File
C Compiler/Linker
Assembler/Linker
Device Programmer
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What is a PICAXE???
‘PICAXE Command Interpreter’
Program
PIC Microcontroller
aka
‘PICAXE’
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Programming the ‘PICAXE’
Flash Program
Memory
User program:
PICAXE commands
User
Program
PICAXE ‘Compiler’
PICAXE
Command
Interpreter
Serial Download
No Device Programmer
required.
QCWA Nov. 18 2008
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‘PICAXE’
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Over 120 PICAXE Commands
• Digital input/output
• Analog input (10-bit ADC)
• Pulse width modulation
• Pulse counting
• Looping and branching operations
• Subroutines
• Off-chip expansion with serial buses
• Low power (Sleep) mode…
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PICAXE Programming
• Easy to learn ‘BASIC-like’ language
top:
QCWA Nov. 18 2008
high 2
;set pin 2 high
pause 500
;delay ½ sec
low 2
;set pin 2 low
pause 1000
;delay 1 sec
goto top
;loop
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Interfacing a PICAXE…
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Interfacing with Digital
Input/Output
high 7 ;enable LED
if pin 3 = 0 then…
high 1 ;enable output
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Driving an Opto-isolator
high 7
;toggle Pin 7
pause dit_length
low 7
pause char_space
High 7
Pause dah_length
Low 7
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Capturing Analog Voltage
readadc10 0, variable0
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Iambic Keyer with Speed Control
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Controlling Motor Speed
using Pulse Width Modulation
Pulse width Modulator
• Single
• Half bridge
• Full bridge
• Duty cycle control
To Motor
Driver
Counter input From
Shaft Encoder
count 4, 100, w1
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Serial Input/Output
Serial transfers to LCD
serout 1,N9600_8,(“Hello")
Transfers to PC serial port
serin 0,T2400_8,b1,b2,b3
serout 0,T2400_8,(10,13,"> ")
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Keyboard Interface
• Uses 2-wire interface.
• Reads keystrokes.
• Control Keyboard LEDs.
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i2c and SPI Serial Bus
• hi2csetup
• hi2cin
• hi2cout
• EPROM
• Static RAM
• Floating point co-processor
• Real time clock…
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PIC vs. PICAXE
PIC16F886
PICAXE-28X1
Ease of
Programming
Complex or not so complex
(C, BA$IC, or Assembly)
Simple
(BASIC)
Performance
(4 MHz Clock)
1 ms/instruction
~330 ms/command
(high/low commands)
Cost (chip)
Oct. 25, $ Can
$3.72
$12.60
Free Software
• MPLAB IDE + Assembler
• HI-TECH C PRO ‘Lite’
PICAXE Program Editor
Device
Programmer
Google!
N/A
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PICAXE
• Revolution Education Ltd. (UK)
– www.picaxe.co.uk
– Education market (secondary and higher)
– Electronics hobbyists
• Products available in Canada from HVW Technologies
– www.hvwtech.com
– ‘AXE-28 Starter Kit C$58.74 (Oct. 29)
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PICAXE-28 Starter Kit
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PICAXE Programming Editor
• A free download! (www.picaxe.co.uk)
• Program development tool.
• Complete documentation set is included.
• Program ‘compiler’ and downloader.
• Simulator.
• Debugging tools.
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The Ottawa Amateur Radio Club
Project
• A hands-on introduction to microcontrollers.
• Algonquin College lab facilities.
• 6 Saturday morning sessions:
– Kit assembly
– Programming tools
– Program development
• Short presentations:
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Programming tools
Manuals and help literature
Debugging
Binary number representation…
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Exercises
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Blinking LEDs.
Morse code generator (LED).
Subroutines.
CW speed control via ADC input.
CW Keyer: coupled via Opto-isolater to a Transceiver.
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Results
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25 participants.
17 on average over each of 6 sessions.
Lots of enthusiasm for the project.
Want to do more…
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Some Examples Microcontroller
Applications for Amateur Radio…
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PIC-based
Rechargeable Battery Conditioner
• Bertrand VE2ZAZ, QEX Sept./Oct. 2008
ADC In
PWM Out
Rechargeable
battery pack
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PIC
To PC for
Setup and
Data Logging
Charge/Discharge
Circuitry
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Examples of Commercial PIC-based
Amateur Radio Gear
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MFJ-259B SWR Analyzer
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LDG Z-100 autotuner
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Examples of PIC-based
Amateur Radio Projects (via Google)
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Frequency counter
Capacitance meter
Digital wattmeter
Microwattmeter
Morse code speedometers, keyers, readers
CW/BPSK Beacon transmitter
Fox hunting transceiver controller
“PeakPack” Packet radio monitoring tool
NUE-PSK standalone PSK modem
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M3 Electronix
Semiconductor Analyzer Kit
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Byonics TinyTrak3
APRS/GPS Position Encoder Kit
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How to Start?
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Check out the literature.
Decide between a PIC and a PICAXE.
Order the hardware.
Download the free development tools.
Have fun!
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Resources
• PIC
– Manufacturer
• www.microchip.com
– Excellent references:
• http://robotag.carleton.ca/resources/technical/pic_introduction.shtml
• www.voti.nl/swp/n_index.html
• PICAXE
– PICAXE developer
– Canadian supplier
– Discussion forum
www.picaxe.co.uk
www.hvwtech.com
www.picaxeforum.co.uk
• Google!
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Questions?
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Additional Material
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Performance Measurements
Using Bit Flipping
top:
out1
high 1
low 1
high 1
command to be measured
low1
goto top
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PICAXE Performance Measurements
Using ‘Bit flipping’
 Most PIC instructions execute in 1
instruction cycle (4 clock periods) or 1 ms
at 4 MHz clock.
 Measured PICAXE output pin maximum
toggle rate (high/low commands)
Setfreq m8
;8 MHz clk
high 2
; toggle out2
low 2
high 2
• 650 ms or 1.5 kHz (4 MHz clock)
low 2
• 320 ms or 3.125 kHz (8 MHz clock)
high 2
 Measured PICAXE high/low command
execution time:
low 2
…
• 330 ms (4 MHz clock)
• 160 ms (8 MHz clock)
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PIC16F886
© 2008 Microchip Technology Inc.
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