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Thread: frequency-meter.
www.piclist.com/techref/index.htm?key=frequency+meter
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face BY : cousensspamBeGone@her.forthnet.gr



Due to the recent interest in freq counters I thought I'd post these
comments on one of them

I've just finished building a frequency meter from a design on the net

; FILE:counter.asm
; CONTENTS:  Simple low-cost 7 digit frequency meter using a PIC16F84
; COPYRIGHT: Peter Halicky OM3CPH
; AUTHORS:   Peter Halicky OM3CPH & Peter Halicky Jr., OM2APH
;
; E-Mail:    spam_OUThalickyspamcepoe.minv.sk
;
; Bratislava, Slovakia, February 1998

I did not consider any of the four digit designs
Four digits cannot give the resolution I want,
though I built it more as an exercise than necessity
(I already have two 8 digit 200mhz Thandar handheld counters)

Anyway apart from me not setting the WDT to "off" the first time
it works well.
The only fault I can see is it shows 00.00002 (20hz) with no input

Draws 40mA @ 5V, gate time is fixed at .1sec, uses 275 bytes of program
space, uses all 13 I/O (if the 4051 were replaced by a 4017 you could
get a spare pin, only reset and clock required, it should also simplify
the program too)

With a 4mhz crystal the calibration values are approx T1=255, T2=78,
T3=11

I think auto off or at least sleep is required on anything that draws
40mA
from a battery.
It would also be nicer with leading zero suppression which would lower
the power consumption too

I would like to hear from anybody who has built this one
FREQUENCY COUNTER
 Model  : WTCNT
 Author : Terry J. Weeder
 Date   : November 18, 1993
   Version: 1.0

It is also 7 digit (more digits would be nicer but would require a four
byte counter.....anyone take the chalenge ?)

It uses a minimum 1x16 lcd and is autoranging with gate times of .1 and
1 sec
but is for a 16c54 (I'll try to change it for a 16f84 )
it uses all 13 I/O (the lcd in 8bit mode)

--
Peter Cousens
email: TakeThisOuTcousensEraseMEspamSTOPspamher.forthnet.gr  phone: + 3081 380534
snailmail:  Folia, Agia Fotini, Karteros, Heraklion  Crete, Greece.

Is it true that they have, on the new version of windows
managed to increase the MTBF from 95 to 98 minutes ?
(That's why they called it 95)

<36262CC4.2240@her.forthnet.gr> 7bit

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