This works but is much too slow to use with a gas engine 6,100 rpm
Main:
' clear the variables and timer
t1_count = 0
TMR1 = 0 : TMR1 = 0 ' not sure why I have to clear it twice
PIR1.0 = 0
' start the timer and let it count for 1 second
T1CON.0 = 1
PAUSE 1000 ' this has to be shorter than 131072 counts
T1CON.0 = 0 ' Stop the timer
' read the variables and check for an overflow
t1_count = TMR1
IF PIR1.0 = 1 THEN t1_count = t1_count + 65536
' send serial message with count, RPM
HSEROUT ["Count = ", DEC t1_count, " RPM = ", DEC (t1_count * 15 ) , 10,13]
GOTO main
This works but a lot of Jitter
'Each Pulse in Tick = 625nS.
'RPM = 60 / (Ticker * 625nS)
'60 / 625nS = 96000000
'RPM_In = 96000000 / Ticker
Tick = 0 ' Set Var to Zero
D_Tick = 0 ' Set Var to Zero
Ticker = 0 ' Set Var to Zero
Pulsin PortB.0 ,1, Tick ' Measure Pulse Time High Per Rev.
RCTIME PortB.0 ,0, D_Tick ' Measure Pulse Time Low Per Rev.
Ticker = (Tick + D_Tick) ' Ticker = Pulse High + Pulse Low
RPM_IN = (96000000 / Ticker) ' 96,000,000 Devide by Ticker = RPM
HSEROUT " RPM = ", DEC RPM_IN , 10,13]
I know that an interrupt code would be much more accurate and more steady do not know how to start making an interrupt driven code
Help Please
Main:
' clear the variables and timer
t1_count = 0
TMR1 = 0 : TMR1 = 0 ' not sure why I have to clear it twice
PIR1.0 = 0
' start the timer and let it count for 1 second
T1CON.0 = 1
PAUSE 1000 ' this has to be shorter than 131072 counts
T1CON.0 = 0 ' Stop the timer
' read the variables and check for an overflow
t1_count = TMR1
IF PIR1.0 = 1 THEN t1_count = t1_count + 65536
' send serial message with count, RPM
HSEROUT ["Count = ", DEC t1_count, " RPM = ", DEC (t1_count * 15 ) , 10,13]
GOTO main
This works but a lot of Jitter
'Each Pulse in Tick = 625nS.
'RPM = 60 / (Ticker * 625nS)
'60 / 625nS = 96000000
'RPM_In = 96000000 / Ticker
Tick = 0 ' Set Var to Zero
D_Tick = 0 ' Set Var to Zero
Ticker = 0 ' Set Var to Zero
Pulsin PortB.0 ,1, Tick ' Measure Pulse Time High Per Rev.
RCTIME PortB.0 ,0, D_Tick ' Measure Pulse Time Low Per Rev.
Ticker = (Tick + D_Tick) ' Ticker = Pulse High + Pulse Low
RPM_IN = (96000000 / Ticker) ' 96,000,000 Devide by Ticker = RPM
HSEROUT " RPM = ", DEC RPM_IN , 10,13]
I know that an interrupt code would be much more accurate and more steady do not know how to start making an interrupt driven code
Help Please