Hi Christian,
I'd like to be sure of one thing : what do you use as a rotation detector ???
... as in your calculations, the pulsin signal is supposed to be equal to the rotation period, something hurts me ... but what ???
Alain
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Hi Christian,
I'd like to be sure of one thing : what do you use as a rotation detector ???
... as in your calculations, the pulsin signal is supposed to be equal to the rotation period, something hurts me ... but what ???
Alain
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Why insist on using 32 Bits when you're not even able to deal with the first 8 ones ??? ehhhhhh ...
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IF there is the word "Problem" in your question ...
certainly the answer is " RTFM " or " RTFDataSheet " !!!
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As it is, I am only using a simulator. I do not have a programmer.Originally Posted by Acetronics
Actually, it's supposed to measure the RPM of a computer-fan. 50% duty-cycle. :-)
/ Lerche
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ThaSanta, Here is a snipit of code I wrote about 4 years ago to do exactly what you are requesting..
ASM
PutMulResult macro Const32
MOVE?CB low Const32, R2
MOVE?CB low (Const32 >> 8), R2 + 1
MOVE?CB low (Const32 >> 16), R0
MOVE?CB low (Const32 >> 24), R0 + 1
endm
ENDASM
PULSIN B_IN,1,POINTER1 'MEASURE HIGH PULSE
IF POINTER1 > 0 THEN
@ PutMulResult 15000000 ' Load PBP internal vars Max= 2,147,483,648
POINTER2 = DIV32 POINTER1 ' Divide 15000000/(PERIOD/2)
SCRATCH = R2 ' Get remainder of Div32
' Change remainder to Decimals
SCRATCH = SCRATCH * 10000 ' Multiply remainder * 10,000
SCRATCH = DIV32 POINTER1 ' Divide remainder by original divisor
ELSE
POINTER2 = 0
SCRATCH = 0
ENDIF
LCDOUT $FE,LINE(1)
PAUSEUS 100
LCDOUT DEC5 POINTER2,".",DEC4 SCRATCH
I hope it works for you... It did for me...
Dave Purola,
N8NTA
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Hey again guys. Long time, no code.
Finally, I got the idea.
- This rountine uses an external freq-to-voltage chip, and reads it using ADCIN, multiplies it, and show the result a lot of times per second.
Here goes.
I'm sorry that there is some comments that shouldn't be in the code. But I've made a lot of changes through time!!Code:'**************************************************************** '* Name : RPM.BAS * '* Author : Christian Lerche * '* Notice : Copyright (c) 2009 DSB El-teknik * '* : All Rights Reserved * '* Date : 28-05-2009 * '* Version : 1.0 * '* Notes : PIC16F913, Boden Off, WDT off, PWR off * '* : * '**************************************************************** ' ' Includes ' ' ' Defines----------------------------------------------------------------------- ' Define osc 10 ' Define oscillator XT 10 MHz DEFINE ADC_BITS 10 ' Define A/D Converter 10 bit DEFINE ADC_CLOCK 3 ' Define ADC clock source DEFINE ADC_SAMPLEUS 50 ' Wait 50 µS before convert to digi ' ' INPUT / OUTPUT---------------------------------------------------------------- ' TRISA = 0 ' PORTA is output TRISA.5 = 1 ' PORTA.5 is input TRISB = 1 ' PORTB is input TRISC = 0 ' PORTC is Output TRISB.0 = 1 ' B0 / Int is count input ADCON0 = %10010001 ' ADC On, right justified ADCON1 = 0 ' ADC Freq = 625KHz ASM ; Insert ASM BANKSEL LCDCON ; LCD Configuration CLRF LCDCON ; Turn off LCD Driver ENDASM ; End of ASM ' ' Variables and constants------------------------------------------------------- ' W1 VAR WORD ' W1 is 16 bit variable W2 var word ' W2 is 16 bit variable W3 var word ' W3 is 16 bit variable B0 var byte ' B0 is 8 bit variable ' ' Main program------------------------------------------------------------------ ' Main: ADCIN 4, W2 ' Read Freq-to-voltage device W3 = W2 * 977 ' Freaky constant makes it work. W1 = DIV32 100 ' Put the result in W1 GOSUB display4 ' Show RPM GOTO Main ' Do forever END ' For the compilers sake ' ' Subroutines------------------------------------------------------------------- ' display4: B0 = W1 / 1000 ' Find number of thousands W1 = W1 // 1000 ' Remove thousands from W1 Lookup B0,[$3F,$06,$5B,$4F,$66,$6D,$7D,$07,$7F,$67],B0 PORTC = B0 ' Send segments to LED PORTA = $01 ' Turn on fourth digit Pause 1 ' Leave it on 1 ms PORTA = $00 ' Turn off digit to prevent ghosting B0 = W1 / 100 ' Find number of hundreds W1 = W1 // 100 ' Remove hundreds from W1 Lookup B0,[$3F,$06,$5B,$4F,$66,$6D,$7D,$07,$7F,$67],B0 PORTC = B0 ' Send segments to LED PORTA = $02 ' Turn on third digit Pause 1 ' Leave it on 1 ms PORTA = $00 ' Turn off digit to prevent ghosting B0 = W1 / 10 ' Find number of tens W1 = W1 // 10 ' Remove tens from W1 Lookup B0,[$3F,$06,$5B,$4F,$66,$6D,$7D,$07,$7F,$67],B0 PORTC = B0 ' Send segments to LED PORTA = $04 ' Turn on second digit Pause 1 ' Leave it on 1 ms PORTA = $00 ' Turn off digit to prevent ghosting B0 = W1 ' Get number of ones Lookup B0,[$3F,$06,$5B,$4F,$66,$6D,$7D,$07,$7F,$67],B0 PORTC = B0 ' Send segments to LED PORTA = $08 ' Turn on first digit Pause 1 ' Leave it on 1 ms PORTA = $00 ' Turn off digit to prevent ghosting RETURN ' Return to caller!
Last edited by ThaSanta; - 19th June 2009 at 02:02. Reason: Adding info
/ Lerche
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Tachometer finally done
Hey All.
I've finally finished my tachometer, with full 4 7 segments displays. It updates very fast, with the calculation, and showing the new RPM's.
- Later I will post the full code, and probably the hardware to convert. It's really cheap, and the only thing you have to change in it, it the potentiometer value, so that 166,6 * the number of cilenders your car have. That's the frequency of the top 5volts. For some of the guys, that doesn't have a squarewave signal generator, to adjust it with, you can grab the schematic of LM2907, and start calculating the resistor the fits the purpose.
My routine is simply the routine from the melabs, site. 4*7 Segments, multiplexed, and a calculator, plus ADC converter, the it updates, more than you'll ever get to see.
It's not finished, cuz i need to remove the first zeroes, before the RPM, cuz it is confusing.
Anyways, schematic and code will be applied this week.
May the code be with you all!
Last edited by ThaSanta; - 5th July 2009 at 01:32. Reason: Spelling errors
/ Lerche
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Great! I'm looking forward to see them!
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Source for the project
Here's the code for the project. I've made it, so it doesn't show the zeroes before the actual RPM.Code:'**************************************************************** '* Name : RPM.BAS * '* Author : Christian Lerche * '* Notice : Copyright (c) 2009 DSB El-teknik * '* : All Rights Reserved * '* Date : 28-05-2009 * '* Version : 1.0 * '* Notes : PIC16F913, Boden Off, WDT off, PWR off * '* : * '**************************************************************** ' ' Includes ' ' ' Defines----------------------------------------------------------------------- ' Define osc 10 ' Define oscillator XT 10 MHz DEFINE ADC_BITS 10 ' Define A/D Converter 10 bit DEFINE ADC_CLOCK 3 ' Define ADC clock source DEFINE ADC_SAMPLEUS 50 ' Wait 50 µS before convert to digi ' ' INPUT / OUTPUT---------------------------------------------------------------- ' TRISA = 0 ' PORTA is output TRISA.5 = 1 ' PORTA.5 is input TRISB = 1 ' PORTB is input TRISC = 0 ' PORTC is Output TRISB.0 = 1 ' B0 / Int is count input ADCON0 = %10010001 ' ADC On, right justified ADCON1 = 0 ' ADC Freq = 625KHz ASM ; Insert ASM BANKSEL LCDCON ; LCD Configuration CLRF LCDCON ; Turn off LCD Driver ENDASM ; End of ASM ' ' Variables and constants------------------------------------------------------- ' W1 VAR WORD ' W1 is 16 bit variable W2 var word ' W2 is 16 bit variable W3 var word ' W3 is 16 bit variable B0 var byte ' B0 is 8 bit variable ' ' Main program------------------------------------------------------------------ ' Main: ADCIN 4, W2 ' Read Freq-to-voltage device W3 = W2 * 9774 ' 9999 / 1023 = 9.774 W1 = DIV32 1000 ' Put the result in W1 GOSUB GETNUM ' Show RPM Goto Main ' Do this forever END ' For the compilers sake ' ' Subroutines------------------------------------------------------------------- ' GETNUM: IF W1 >= 1000 THEN display4 IF W1 >= 100 THEN display3 IF W1 >= 10 THEN display2 IF W1 >= 0 THEN display1 display4: B0 = W1 / 1000 ' Find number of thousands W1 = W1 // 1000 ' Remove thousands from W1 Lookup B0,[$3F,$06,$5B,$4F,$66,$6D,$7D,$07,$7F,$67],B0 PORTC = B0 ' Send segments to LED PORTA = $01 ' Turn on fourth digit Pause 1 ' Leave it on 1 ms PORTA = $00 ' Turn off digit to prevent ghosting display3: B0 = W1 / 100 ' Find number of hundreds W1 = W1 // 100 ' Remove hundreds from W1 Lookup B0,[$3F,$06,$5B,$4F,$66,$6D,$7D,$07,$7F,$67],B0 PORTC = B0 ' Send segments to LED PORTA = $02 ' Turn on third digit Pause 1 ' Leave it on 1 ms PORTA = $00 ' Turn off digit to prevent ghosting display2 B0 = W1 / 10 ' Find number of tens W1 = W1 // 10 ' Remove tens from W1 Lookup B0,[$3F,$06,$5B,$4F,$66,$6D,$7D,$07,$7F,$67],B0 PORTC = B0 ' Send segments to LED PORTA = $04 ' Turn on second digit Pause 1 ' Leave it on 1 ms PORTA = $00 ' Turn off digit to prevent ghosting display1 B0 = W1 ' Get number of ones Lookup B0,[$3F,$06,$5B,$4F,$66,$6D,$7D,$07,$7F,$67],B0 PORTC = B0 ' Send segments to LED PORTA = $08 ' Turn on first digit Pause 1 ' Leave it on 1 ms PORTA = $00 ' Turn off digit to prevent ghosting RETURN ' Return to caller!
I hope some of you can use it. Later I'll post the schematic for F/V converter
** EDIT **
Here's the schematic for the F/V Converter. For the 8V source, i use a small regulator, so that the car can run between 12 and 13.8 V at the battery. Depending on the source to the converter, the potentiometer is turned, until satisfied. Mine will run of the 12V to the ignition coil, so that i have 4 pulses for one revolution of the engine.
Depending on your choice of pulses, you may use a Frequency generator, at square-wave, and if your car pulses 4 times per revolution, then adjust it, until you get 5V out, at 4*166.66.
If the car pulses once per revolution, set your frequency generator to 166.66 (mine was digital), and adjust the potentiometer until 5V is reached.
You've now succesfully made a digital tachometer, that updates faster than the code could ever do, by it self.
Good luck, and have fun all of you!
Last edited by ThaSanta; - 24th July 2009 at 03:28. Reason: Adding F/V Schematic
/ Lerche
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