Help required
Hello Steve,
I have run into some problem using your code for a 16F628A with a 16x2 LCD.
I am basically making a audio frequency counter, which would then be used to control a set of 8 LED's depending upon the Input frequency on PORTB.
Keeping this in mind I tried to output the frequency on the LCD but I get jumping figures at high speed. I believe , I have to introduce a delay between the display. Secondly , connecting 10K to ground on Pin#3 with 1K in series , as your circuit says, I don't get any reading. Which means , I need some impedence matching or may be a signal conditioner.
My audio source is from my desktop computer , audio out.
my code so far -
Code:@ __CONFIG _HS_OSC & _MCLRE_OFF & _LVP_OFF & _WDT_ON & _PWRTE_ON & _BODEN_ON DEFINE OSC 20 ;76543210 TRISB = %00000000 TRISA = %11110000 DEFINE LCD_DREG PORTB 'Define PIC port used for LCD Data lines DEFINE LCD_DBIT 0 'Define first pin of portb connected to LCD DB4 DEFINE LCD_RSREG PORTB 'Define PIC port used for RS line of LCD DEFINE LCD_RSBIT 5 'Define Portb pin used for RS connection DEFINE LCD_EREG PORTB 'Define PIC prot used for E line of LCD DEFINE LCD_EBIT 4 'Define PortB pin used for E connection DEFINE LCD_BITS 4 'Define the 4 bit communication mode to LCD DEFINE LCD_LINES 2 'Define using a 2 line LCD 'DEFINE LCD_COMMANDUS 2000 'Define delay between sending LCD commands 'DEFINE LCD_DATAUS 50 'Define delay time between data sent. ' Interrupt and register definition ' --------------------------------- ' OPTION_REG = %1111000 ' TMR0 clock source : RA4/T0CKI ' increment on low to high transition ' Prescaler assign to WDT ' WDT rate 1:1 ' INTCON = %10100000 ' Enable global interrupt ' Disable EE write interrupt ' Enable TMR0 overflow interrupt CMCON = 7 ' disable analog comparator VRCON = 0 'turns off Vref for min current ' Variable definition ' ------------------- ' DisplayPort var PORTB ' Port for 7 Segments ClockInput var PORTA.4 ' Input pin for signal _7Seg1 con 14 ' enable more significant 7 segment display _7Seg2 con 13 ' enable mid significant 7 segment display _7Seg3 con 11 ' enable less significant 7 segment display Digit_1 var byte ' Hundreds digit Digit_2 var byte ' Tenth digit Digit_3 var byte ' Unit digit ToBeDisplay var word ' Result of count to be send to 7 segment display Display var byte ' Temp variable DisplayLoop var byte ' Delay var word ' Variable for Delay loop OverFlowVar var word ' Thousands var bit ' Flag for count >= 1000 & < 10 000 TenThousands var bit ' Flag for count >= 10 000 ' Variable and software initialisation ' ------------------------------------ ' tobedisplay = 0 ' set initial value of count TMR0 = 0 ' reset prescaller on interrupt goto SetVarToBeDisplay MainLoop: ' MainLoop ' --------- ' ' 1. display the result of the count on RA4 pin ' 2. refresh display ' 3. reset Timer0 ' 4. reload prescaler. ' ' Duration of the procedure : 1 sec ' fine tuned by DelayBetweenEachDisplay Sub ' ' Looping 1 sec and get results of the pulse count in ' TMR0 + OverFlowVar ' DisplayRefresh: ' ' Testing amount of count ' ----------------------- ' ' Get the result of count and place decimal point flag ' on the according 7 segments ' If tobedisplay>=1000 then tobedisplay=tobedisplay/10 if tobedisplay>=1000 then tobedisplay=tobedisplay/10 Thousands=0 TenThousands=1 else TenThousands=0 thousands=1 endif else thousands=0 tenthousands=0 endif LCDOut $FE,$C0, "COUNT: ",DEC tobedisplay , " " gosub DelayBetweenEachDigit tobedisplay = OverFlowVar + TMR0 OverFlowVar = 0 ' Reset OverFlowVar TMR0 = 0 ' reset prescaller goto DisplayRefresh goto DisplayRefresh goto DisplayRefresh goto DisplayRefresh goto DisplayRefresh goto DisplayRefresh DelayBetweenEachDigit: ' DelayBetweenEachDigit ' --------------------- ' Produce delay of about 3 mSec ' ' Fine tuned with MPLAB StopWatch to get MainLoop = 1 sec ' for delay=1 to 307 @ nop next @ nop @ nop @ nop @ nop @ nop @ nop @ nop return disable SetVarToBeDisplay: ' ' SetVarToBeDisplay ' ----------------- ' interrupt routine of TMR0 overflow ' ' Reset prescaller ' Reset overflow flag ' OverFlowVar = OverFlowVar + 256 INTCON.2 = 0 ' clear overflow flag TMR0 = 0 ' reload TMR0 resume enable
Originally Posted by charudatt
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