Time'n and Count'n using PIC®
Microcontrollers - $34.95
(replaces PIC'n Techniques)
 by David Benson
"Time'n and Count'n" © is an intermediate level book on
16-bit timing and counting applications using Microchip Technology's PIC®
microcontrollers. More opportunities for creating fun projects are described.
Learning to use timer 1 (TMR1) with it's powerful capture, compare and pulse
width modulation (PWM) modes will expand your PIC microcontroller design
capabilities significantly. TMR1, which is an on-board feature of many of the
mid-range PIC microcontrollers, is a 16-bit timer/counter. The maximum count is
65,535 vs. 255 for timer 0 (TMR0). This is a big help! TMR1 used in conjunction
with the capture, compare, PWM (CCP) module may be programmed to do useful
things unattended leaving the PIC free to perform other tasks. A special pin may
be used for external inputs to TMR1 and another special pin may be used as an
external output from TMR1. The techniques presented in the book are useful for
generating single time intervals and free running outputs as well as for
measuring period and frequency. PWM using TMR1 unattended is also described.
These timing and counting techniques serve as the basis for designing and
building your own period and frequency generating and measuring test equipment
as described in the book.
This book gives example programs in assembly language only.
8-1/2 x 11 format, 218 pages.
Table of Contents
- INTRODUCTION
- TEST EQUIPMENT FOR TIMING AND COUNTING EXPERIMENTS
- Test equipment for detecting a short single pulse and
measuring it's width
- Pulse generator - 32 microseconds
- Pulse generator - 128 microseconds
- Pulse generator - 2000 microseconds
- Pulse generator - 65280 microseconds
- Test equipment for generating a frequency output
- USING TIMER 1, TIMER 2 AND THE CAPTURE/COMPARE/PWM (CCP) MODULE
- PIC16F870 test circuit
- Before we take off
- TMR2: 8-bit timer
- TMR2 description
How to choose/select mode of operation
Interrupts
TMR2 applications
Free running mode (via TMR2 interrupt)
Free running mode (via period register)
TMR1: 16-bit timer/counter and capture/compare module
- TMR1/CCP module simplified
- TMR1 description
- CCP module - capture mode
- CCP module - compare mode
- CCP module - PWM mode
- How to choose/select mode of operation
T1CON register
CCP1CON register
- Interrupts
- Reading and writing TMR1
- Long time intervals
- Controlling the CCP1 pin in compare mode
- More than one way to do timing stuff
Timing and counting experiments
- Free running output (via TMR1 interrupt)
- Event counting (via TMR1)
Count events, read TMR1 contents
Capture TMR1 count when external event occurs
Count events up to predetermined number and
generate an output (compare)
- Single time interval output (via TMR1 and CCP,
compare mode)
Start TMR1, auto end
500 milliseconds
128 microseconds
- Free running output (via TMR1 and CCP, compare mode)
Clear TMR1 each cycle
Free running TMR1, add interval value to
compare register each cycle
- Time measurement (period/interval/time between events)
- (via TMR1 read)(interval input via port pin)
- (via TMR1 and CCP, capture mode)(interval input
via CCP1 pin,
two
captures,subtract)
- Frequency measurement
(via TMR1, gate via TMR0)
- External 32,768 Hz watch crystal-based clock for TMR1
Pulse width modulation (PWM) using TMR2 and the CCP module
- Analog output - increase/decrease buttons - PWM - 8-bit mode
- Duty cycle - 10-bit mode
- Analog output - increase/decrease buttons - PWM - 10-bit mode
- DESIGNING AND BUILDING YOUR OWN TEST EQUIPMENT
Keypad/LCD user interface
- 5-digit decimal to 16-bit binary entry program
- Using the 5-digit decimal to 16-bit binary entry program
Digital pulse generator
Digital frequency generator
Time interval measurement instrument
Frequency measurement instrument
Creating your own combination signal generator and
measurement instrument
APPENDIX A - Program listings vs. page number
APPENDIX B - PICF870 control registers
APPENDIX C - '84 on a board
APPENDIX D - PIC/LCD schematic and code
APPENDIX E - Keypad
APPENDIX F - Using the ICD
APPENDIX G - Sources
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