Help with DT's 16-bit averaging subroutine?

I am trying to get DT's 16-bit averaging subroutine to work correctly. I created the attached code as a way to test it. As you can see from the code, it writes values at various locations in the code to EEPROM so that after each execution I can read the data from the EEPROM as a way to see what values are being created.
What I don't undestand and am asking for help from anyone on this forum is why the variable VALUE is always showing up as zero (EEPROM addresses 19 and 36). By the way I set up this test routine, starting with a decimal value of 35260 and incrementing it 6 times, the average stored in VALUE should be 35263...not zero.
Any help is appreciated on this.

Code:

'***************************************************************** '* Name : TEST_AVERAGE2.BAS * '* Author : John R. Ellis * '* Notes : Adapted from code by Darrel Taylor * '* "This routine will keep a "Running Average. * '* Instead of adding a bunch of values together and then dividing* '* by the number of samples, it averages each sample into the * '* final result immediately. This eliminates the need for 32 bit * '* math. * '* To allow it to "Catch up" to large changes, set the FAspread * '* to an acceptable range. Simply place the new number in VALUE * '* and GoSub AVERAGE The Average will be returned into the same * '* variable VALUE." * '* Memory : 546 Words of program memory required * '***************************************************************** ADavg VAR WORD AvgCount CON 16 ' = Number of samples to average FAspread CON 1000 ' = Fast Average threshold +/- i VAR Byte ' Index for measurment loop pw VAR WORD ' Stores each pw measurment pw0 Var pw.BYTE0 ' LSB of pw value PW1 var PW.BYTE1 ' MSB of pw value range VAR WORD ' Stores calculated range value range0 VAR range.Byte0 ' LSB of range value range1 VAR range.Byte1 ' MSB of range value us_inch con 147 ' Scale factor converts sensor 147 microsecs to inches VALUE VAR WORD ' Stores average of measurements value0 VAR value.byte0 ' LSB of value value1 VAR value.byte1 ' MSB of value GOTO Main ' Jump over Subroutines ' -----------------{ Subroutines }---------------------------------------- Average_Single: 'Embedded use of Darrel Taylor's 16 bit averaging routine ' USE INTRUCTIONS: First, Select the sensor. ie. Sensor = Temperature ' then place the new number in VALUE and then GoSub AVERAGE_SINGLE. ' The Average will be returned into the same variable VALUE. IF Value = ADavg Then NoChange IF ABS (Value - ADavg) > FAspread OR Value < AvgCount Then FastAvg IF ABS (Value - ADavg) < AvgCount Then RealClose ADavg = ADavg - (ADavg/AvgCount) ADavg = ADavg + (Value/AvgCount) GoTo AVGok FastAvg: ADavg = Value GoTo AVGok RealClose: 'If averaging less than 8 samples, change AvgCount/4 to AvgCount/2. ADavg = ADavg - (ADavg/(AvgCount/2)) ADavg = ADavg + (Value/(AvgCount/2)) AVGok: Value = ADavg ' Put Average back into Value NoChange: Return '-------------------------------------- Main: 'DEFINE WRITE_USED 1 'Required if only writing WORD variables in version 2.6 pw = 35260 WRITE 32,pw ' Comment out for test only For i = 0 to 5 'PULSIN PORTA.4,1,pw ' Make 5 measurements from PW pin ' of transceiver into array pw(i) ' with running average in value pw = pw +1 ' Simulates pw measurement WRITE 34,pw ' Comment out for test only Value = pw WRITE 36,VALUE ' Comment out for test only 'Running average in value...Max pw = 20' = 240" = 35280 usec. Therefore 'pw, value, & range are 16 bit WORDs. GOSUB Average_Single NEXT WRITE 17,i ' Comment out for test only WRITE 19,VALUE ' Comment out for test only range = (Value / us_inch) +1 ' Convert value to range in inches (max 240) ' add 1 to account for division rounding. WRITE 21,range ' Store day's range in EEPROM location END

If you want to write WORD variables to EEPROM, you need to either add the WORD modifier to the WRITE statement, or WRITE the lowbyte and highbyte seperately in 2 WRITE statements.

Code:

WRITE 36,WORD VALUE

Re: Help with DT's 16-bit averaging subroutine?

OK, Darrel,...that is one stupid mistake on my part. But I fixed the WRITE statements per the attached code, and VALUE is still coming out of the subroutine with a value of zero, as evidenced in the EEPROM WRITE address 19. Yet when I WRITE to EEPROM address 36 within the loop where the subroutine is called, the values in VALUE are correct going into the averaging subroutine.
I still can't figure out why the averaging isn't working?? Any ideas?

Code:

'***************************************************************** '* Name : TEST_AVERAGE2.BAS * '* Author : John R. Ellis * '* Notes : Adapted from code by Darrel Taylor * '* This routine will keep a "Running Average". * '* Instead of adding a bunch of values together and then dividing* '* by the number of samples, it averages each sample into the * '* final result immediately. This eliminates the need for 32 bit * '* math. * '* To allow it to "Catch up" to large changes, set the FAspread * '* to an acceptable range. Simply place the new number in VALUE * '* and GoSub AVERAGE The Average will be returned into the same * '* variable VALUE. * '* Memory : 546 Words of program memory required * '***************************************************************** ADavg VAR WORD AvgCount CON 16 ' = Number of samples to average FAspread CON 1000 ' = Fast Average threshold +/- i VAR Byte ' Index for measurment loop pw VAR WORD ' Stores each pw measurment pw0 Var pw.BYTE0 ' LSB of pw value PW1 var PW.BYTE1 ' MSB of pw value range VAR WORD ' Stores calculated range value range0 VAR range.Byte0 ' LSB of range value range1 VAR range.Byte1 ' MSB of range value us_inch con 147 ' Scale factor converts sensor 147 microsecs to inches VALUE VAR WORD ' Stores average of measurements value0 VAR value.byte0 ' LSB of value value1 VAR value.byte1 ' MSB of value GOTO Main ' Jump over Subroutines ' -----------------{ Subroutines }---------------------------------------- Average_Single: 'Embedded use of Darrel Taylor's 16 bit averaging routine ' USE INTRUCTIONS: First, Select the sensor. ie. Sensor = Temperature ' then place the new number in VALUE and then GoSub AVERAGE_SINGLE. ' The Average will be returned into the same variable VALUE. IF Value = ADavg Then NoChange IF ABS (Value - ADavg) > FAspread OR Value < AvgCount Then FastAvg IF ABS (Value - ADavg) < AvgCount Then RealClose ADavg = ADavg - (ADavg/AvgCount) ADavg = ADavg + (Value/AvgCount) GoTo AVGok FastAvg: ADavg = Value GoTo AVGok RealClose: 'If averaging less than 8 samples, change AvgCount/4 to AvgCount/2. ADavg = ADavg - (ADavg/(AvgCount/2)) ADavg = ADavg + (Value/(AvgCount/2)) AVGok: Value = ADavg ' Put Average back into Value NoChange: Return '-------------------------------------- Main: 'DEFINE WRITE_USED 1 'Required if only writing WORD variables in version 2.6 pw = 35260 WRITE 32,WORD pw ' Comment out for test only For i = 0 to 5 'PULSIN PORTA.4,1,pw ' Make 5 measurements from PW pin ' of transceiver into array pw(i) ' with running average in value pw = pw +1 ' Simulates pw measurement WRITE 34,WORD pw ' Comment out for test only Value = pw WRITE 36,WORD VALUE ' Comment out for test only 'Running average in value...Max pw = 20' = 240" = 35280 usec. Therefore 'pw, value, & range are 16 bit WORDs. GOSUB Average_Single NEXT WRITE 17,i ' Comment out for test only WRITE 19,WORD VALUE ' Comment out for test only range = (Value / us_inch) +1 ' Convert value to range in inches (max 240) ' add 1 to account for division rounding. WRITE 21,WORD range ' Store day's range in EEPROM location END

2 Attachment(s)

Re: Help with DT's 16-bit averaging subroutine?

Maybe you've worn out your EEPROM.
I never liked that debugging method.

I've run it here and it works fine on a 16F887.

Here's a run in Proteus.

Attachment 5303

And here's a readback from a real chip running the same program.

Attachment 5304