Originally Posted by
mister_e
mmm, could be a noisy pot as well... using your code and on many low-value ADC.. they are all stable.. no noise, no frlicker.
what happen if you stick a 0.1 uF in parallel with your POT wiper?
Any 0.1uF + 10uF capacitor close to your PIC?
I just tried with a 20 turn 10k linear pot and its the same, once I reach the lower duty cycles the led flickers.
The difference is clearly visible with the multiturn pot, once you go below a certain level it flickers, move the other way a little bit and the flicker goes away
Reading in the flicker position I get this range: from $00BB to $00BF and spurious $009F , $00B4, $00C6, $00E3 at random places
Reading in the steady position I get this range: $00CD to $00CF and no spurious readings
I only read 125 word values into the device own eeprom.
Again Im using a li-ion battery for powering the circuit (3.65v)
Weird isnt it? even weirder is that sometimes when I write the values to eeprom the written values are steady (also visually) but only when writting...
Just in case here is the code I used:
Code:
' Pic Configuration
@ device pic12f683,INTRC_OSC_NOCLKOUT , wdt_on, mclr_off, protect_off
' Hardware configuration
' I/Os
TRISIO = %00010010 ' pin1 is ADC , pin4 is the calibration button
' ADC's
ANSEL = %00000010
DEFINE ADC_BITS 10 ' ADCIN resolution (Bits)
DEFINE ADC_CLOCK 1 ' ADC clock source (Fosc/8)
DEFINE ADC_SAMPLEUS 11 ' ADC sampling time (uSec)
ADCON0.7 = 1 ' Right justified results
' Comparator
CMCON0 = %00000111 ' Disable comparator
VRCON = %00000000 ' disable
'cmcon0 = %00001110 ' Multiplexed Input with Internal Reference CIS=1
'vrcon = %10001010 ' set vref=2.25v (from 4v input)
include "HPWM10.pbp"
' definitions
pote var word
Frequency var word
calibraled var gpio.5
calibrapin var gpio.4
conta var byte
gpio=0
conta=0
frequency=1000
pause 50 ' coffee break
loop:
adcin 1, pote
if pote>1000 then pote=1000
if calibrapin=1 then
if conta < 250 then
write conta, pote.byte1
write conta+1, pote.byte0
conta=conta+2
endif
endif
@ HPWM10 1, _pote, _Frequency
pause 10
goto loop
end
Pablo
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