PIC Microcontoller Time Methods

Clocks@, Time Standards@, Real Time@ and Delays,

• PIC specific oscillators and delays
• Code generator  for Delays by Nikolai Golovchenko Wow!
• Clocks esp. crystal oscillators@
• Watch Dog Timers@
• Counters and counting. +
• Run a xtal oscillator PIC16f872 to exactly 1000 hertz
• PIC countdown on 4, 7 segment LED's timer 16F84A
• PIC 16F84A elapsed time counter on 4, 7 segment LED's
• PIC long term timer without interrupts
• Timer tutorial (incl prescalers)
• Compinsating for ISR time loss in a time sensitve main code loop
• Converting BCD RTC formats by Drew Vassallo
• NJU6355 E or G version Real Time Clock interface code by Andrew D. Vassallo
• Easy Interrupt sample
• 16F676 Real Time Clock by Edwin Tugano Jr.
• YET ANOTHER TIMER TUTORIAL 18F452 based by John Nall

From the CHEAPIC tutorial:

• bincnt.asm - Count in binary on 4 LEDs
• swcnt.asm - Count switch closures.
• eggtimer.asm - Countdown timer, displays minutes and 10's of seconds on LEDs
• morsenbr.asm - Send numbers 0-9 out on piezo speaker
• binclock.asm - A clock which displays hours and minutes in BCD on LEDs at keypress
• worktime.asm - Uses a LCD to display a timer that can be started and stopped by pushbutton
• shotmr0.asm - Display TMR0 on a LCD atter counting pulses on RA4 for one second

Also:

• Interrupts@
• Debounce@

See also:

• Richard H McCorkle of Solid State Services refers to /techref/member/RHM-SSS-SC4/TIC232.htm member RHM-SSS-SC4 TIC232+
• http://www.time.com interesting
• http://stud.uni-sb.de/~maro0019/delay05.asm
• http://www.people.cornell.edu/pages/shb7/lop.html
• http://www.skyinet.net/~ecb/#isochronous delay
• Microchip app note "Technique to Calculate Day of Week"
• http://www.rt66.com/~shera/ppsdiv.zip The PIC source code for a single chip frequency divider that takes a 10 MHz input and produces 9 square wave outputs - one for each frequency decade from 100 kHz to 0.001 Hz (1000 s period), courtesy of Tom Van Baak, tvb@veritas.com:
• http://www.rt66.com/~shera/index_fs.htm Brooks Shera's GPS-Controlled Frequency Standard
• http://www.elecdesign.com/magazine/1998/sept0198/ifd/3IFD.pdf "Microcontroller controls its own clock speed" One chip and 2 xtals.

Archive

• PICList post "Timer Tribulations" Using house mains w/o pugging in
• PICList post "Timer Tribulations"
• PICList post "simple one-second timer"

Code:

Questions:

• SPAMsreerangap at SPAMyahoo.com asks:

  i am using Pic 18c452. i am using Hitech C compiler and i am unable to get how the prescaler is used and how the Tmr0l and Tmr0H should be assigned . plz do explain to me how to get acquianted with the timer. Thanking you sree

• Omar Fathalllah asks:

  I'm just starting to experiment with the PIC16F877 using the HITECH C compiler. I am running the PIC at 10 Mhz and want a 50 MHz PWM period with a 7.5% duty cycle. However this means that I need the PR2 to be 3124 which is too large (max is 255 right?). Is there a way around this? am I doing something wrong? or do I have to use a 4MHz clock instead? or maybe create my own pulse using TIMER0 which would allow a prescalar of 256? Thanks in advance!

Archive:

• List post "16 bit Mod 7 Math" useful for calculating the Zeller Congruence +
• PICList post "BCD time-of-day addition" +

See:

• /techref/piclist/cheapic/eggtim4m.asm
• /techref/microchip/math/index.htm PIC Microcontoller Math Methods+
• /techref/microchip/math/basic.htm PIC Microcontoller Basic Math Methods+
• /techref/microchip/math/incdec/index.htm  PIC Microcontoller Basic Math Inc/Dec Methods
• /techref/microchip/12ceeprom.htm PIC Microcontoller Memory Method - Internal EEPROM access on 12CExxx devices
• /techref/microchip/io/audio.htm PIC Microcontoller Audio Input / Output +
• /techref/microchip/math/filter.htm PIC Microcontoller DSP Math Methods+
• /techref/microchip/edgedetect.htm Detecting riseing and falling edge events+
• /techref/microchip/sersamp.htm PIC Microcontoller IO Method High speed serial IO pin sampleing+
• /techref/microchip/ios.htm PIC Microcontoller Input / Output Methods+
• /techref/microchip/index.htm Technical Reference - MicroChip Technologies - PIC Embedded Controller+

  .