how do I speed up an existing pic18f2525 program ?

[J_norrie]

Hi there, I am trying to get my existing program that outputs 2-3 readings per second of serial data at 19200 at an internal clock frequency of 8Mhz. If I increase the clock frequency to 25Mhz by fitting an external HS crystal, I dont seem to get many more readings per second. PS I changed the Oscillator to HS in the INC file
Here is my code can anyone advise on what is wrong.

thanks again in advance John

' file      : RS232CW.bas 
' author    : John Norrie
' date      : 26/10/10
' purpose   : Seariak output of load and battery condition
' includes  : none
' notes     : 10.00 te weight Read 16 bit ADC, convert to actual load value,    
'           : 
'             inverted 19200 baud value is 16416 used direct wire no 232 driver chip
'             at pic end. AD7705 gain set to 4,unipolar 20hz  cal test 178k//702R = 1mV/V or     kg
'             pic pin 18 RX to 9 way 'D' pin 2   crossed at rx end
'             pic pin 17 TX to 9 way 'D' pin 3   crossed at rx end
'             AD627 gain resistor 909R 0.1 % = gain of approx 200 
'             Bridge  output      mV/V for 10.00 te  Cal = 0.681mV/V =      te
'             Bridge supply 2.5VDC REF03
'             battery low set at 4.0vdc for 6.0v (4xC type bats) in via 2 x 5M5 resistor potential divider
' compiler  : PICBasic Pro Compiler Ver 2.50A   


   

PAUSE 1000 ' Allow power to stabilize on power-up
        
  '   Variable definition
'::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
DEFINE OSC 25
OSCTUNE = %11111100 ' external primary osc block 
'DEFINE LOADER_USED 1 ' Comment out if not using boot-loader
INCLUDE "modedefs.bas"

        INTCON2.7 = 0   'enable weak pull-ups on PORTB
        output portc.4  ' set pin to output operates cal relay
'AIN Channel setup        
        DEFINE ADC_BITS 10
        DEFINE ADC_CLOCK 5              ' Set clock source (rc = 3)
        DEFINE ADC_SAMPLEUS 5000           
        ADCON1 = %00001101              ' Set PORTA analog and select chs
        ADCON2 = %10111110              ' Set PORTA analog and right justify res
        ADCON0 = %00000001              ' Set enable analog 
'AD7705 setup
       
        output portb.7  'adc Clock pin
        output portA.5  'AD7705 Data in pin
        input portA.4   ' AD7705 Data out pin 
        input portA.3   'AD7705 Ready pin
        input portA.0   ' Battery voltage input
        input portA.1   ' Overload setting voltage input
        symbol SCK=PORTB.7 'Clock pin
        Symbol SI=PORTA.5 ' AD7705 Data in pin
        Symbol SO=PORTA.4' AD7705 Data out pin 
        Symbol ADCready = PortA.3 'AD7705 Ready pin
        'Symbol CS = PORTA.2'AD7705 Chip Select pin
        symbol CalOut=PORTc.4
        
     
'AD7705 variables
        adcSend var Byte 'byte sent to communication register of AD7705
        adcrec  var Byte 'byte received from AD7705:only for communication register, set-up register and clock register (8 bit registers)
        ad1     var Word 'ad converter value read from AD7705
        'ad2     var Word 'ad converter value read from AD7705 
' ADC variables        
        Volt1       var word
        VoltsA      var word
        Voltx       var word
        Total1      var word
        i           var byte
        pass        var byte
        MaxVal      var byte
        MinVal      var byte 
        Load        var word 
        ADCvalue    var word
        gtare       var byte
        counts      var byte  
        ScaleBits   con 4096 '12 bit 
        z VAR Byte
        c VAR Byte
        B0 var byte
        B1 VAR BYTE
        B2 VAR word
        d0 VAR BYTE
        d1 VAR BYTE
        d2 VAR BYTE
        d3 VAR BYTE
        p0 VAR BYTE
        p1 VAR BYTE
        p2 VAR BYTE
        p3 VAR BYTE
        t0 VAR BYTE
        t1 VAR BYTE
        t2 VAR BYTE
        t3 VAR BYTE
        
        x VAR Byte
        p VAR Byte
        a VAR Byte
        b VAR Byte
        v VAR Byte
        tm var word
        ' Define keypad program variables
     col        var byte ' Keypad column
     row        var byte ' Keypad row
     key        var byte ' Key value
     press      var byte
     db         var byte
        Total VAR WORD
        totaly var word
        Value VAR WORD
        Value1 VAR WORD
        Tare VAR WORD
        TXBat var word
        TXBat1 var word
        RXBat var byte
        Loadx var word
        Loady var word
        Range var word
        NewVal var word
        
        Calval    var word
        Cal1      var byte  
        peak       var Word
        peak1      var byte
        peak2      var byte
        load1      var byte
        load2      var byte
        CX         var byte
        DAout      var word
        cal1 = 100
           B0 = 0
        B2 = 0
        tare = 0
        Range = 2000
        Calval = 850
        volt1 = 0
        peak = 0
        CX = 1
        calout = 0
        key = 20
        counts = 0
'EEPROMDATA:
'write 1,Cal1
'write 4,Calval.byte0 :write 5,Calval.byte1
'write 6,Range.byte0 :write 7,Range.byte1 
Read 1,Cal1 
Read 6,Range.byte0 :Read 7,Range.byte1 
'Read 2,Tare.byte0 :read 3,Tare.byte1
if range < 1000 then range = 2000
if range > 2500 then range = 2000
if Cal1 < 1 then Cal1 = 100
if Cal1 > 255 then Cal1 = 100 
Calval = Cal1 + 600  
Tare = 0

        
' Main software
Start:   
        
        gosub MAX7705
        gosub calibrate
        gOTO Main
        
Main:   
        
        gosub ADCloop
        gosub GetBatValue
        volt1 = Newval
        gosub AutoZero 
        gosub GetDigits   
        SEROUT2 PortC.6,16416,["L",#d3,#d2,".",#d1,#d0,"B",#t2,#t1,#t0]   '19200 baud
        goto Main

 GetDigits:
 d3 = Volt1 Dig 3 
 d2 = Volt1 Dig 2 
 d1 = Volt1 Dig 1 
 d0 = Volt1 Dig 0
 t3 = txbat Dig 3 
 t2 = txbat Dig 2 
 t1 = txbat Dig 1 
 t0 = txbat Dig 0
 
 return              
MAX7705: 
        tare = 0
        gosub MX7705Ini
        pause 50
        gosub mxch1
        gosub mxcal1
        return
        
ADCloop:   
           gosub getad1
           return
getad1: 'for counterA = 0 to 15
        Total1 = 0
        For x = 1 to 8  
           adcsend=$38 ' Read the 16 bit DATA Register, channel 0.
        shiftout SI, SCK, 5, [adcsend\8] ' adcsend read command and data register address
        shiftin SO, SCK, 6, [ad1\16] ' Read 16 bit data
        While ADCready = 1 'wait for valid data to be received
        Wend 'wait for valid data to be received
        value1 = abs (ad1/8)
        Total1 = Total1 + value1
        next x
        value1 = abs (Total1/16)      '65535/8 = 8192
        if value1 < 1  then value1 = 0
        if value1 > 4096 then value1 = 4096
        value = value1 * Range
        NewVal = div32  ScaleBits  ' scalebits = 4096 (12 active bits)
        return
        
GetAdValue: 
        Total1 = 0
        For x = 1 to 8  
           adcsend=$38 ' Read the 16 bit DATA Register, channel 0.
        shiftout SI, SCK, 5, [adcsend\8] ' adcsend read command and data register address
        shiftin SO, SCK, 6, [ad1\16] ' Read 16 bit data
        While ADCready = 1 'wait for valid data to be received
        Wend 'wait for valid data to be received
        ADCvalue = abs (ad1/8)
        Total1 = Total1 + ADCvalue
        next x
        ADCvalue = abs (Total1/16)  ' 4096 bits
        return        


               
AutoZero:
If volt1 < 3 then
counts = counts + 1
goto  AutoZ
else
counts = 0
endif
return
AutoZ:
if counts = 5 then
volt1 = 0
counts = 0
endif
return

MX7705Ini:
       'Reset MX7705
       adcsend=$ff
       adcrec=$ff
    shiftout SI, SCK, 5, [adcsend\8] ' adcsend command to communication register
    shiftout SI, SCK, 5, [adcrec\8] ' adcsend value to the selecte register
    shiftout SI, SCK, 5, [adcsend\8] ' adcsend command to communication register
    shiftout SI, SCK, 5, [adcrec\8] ' adcsend value to the selecte register
    return
'SetADGAIN:
' if gainval = 1 then ADGAIN = $44  'decimal  68  gain = 1
' if gainval = 2 then ADGAIN = $4c  'decimal  76  gain = 2
' if gainval = 3 then ADGAIN = $54  'decimal  84  gain = 4
' if gainval = 4 then ADGAIN = $5c  'decimal  92  gain = 8
' if gainval = 5 then ADGAIN = $64  'decimal 100  gain = 16
' if gainval = 6 then ADGAIN = $6c  'decimal 108  gain = 32
' if gainval = 7 then ADGAIN = $74  'decimal 116  gain = 64
' if gainval = 8 then ADGAIN = $7c  'decimal 124  gain = 128
' return    
mxch1:'CH1 AD7705 set-up Start. SEE AD7705.XLS  FOR TABLE OF SETTINGS
adcsend=$20 ' WRITE TO THE COMMUNICATIONS REGISTER. SELECT CHANNEL 0 AND SET NEXT OPERATION AS A WRITE TO THE CLOCK REG
' CLOCK REGISTER.(0x20)
adcrec=$00 ' write on clock register: clock division=1, clock bit=1, master clock enabled (bit set to 0),
' bit output rate set to 20hz
gosub mxsend
'adcsend=$28
'GOSUB adread
return

mxcal1: 'CH1 Calib 'self-calibration
adcsend=$10 ' WRITE TO THE COMMUNICATIONS REGISTER. SELECT CHANNEL 0 AND SET NEXT OPERATION AS A WRITE TO THE SETUP REGISTER.(0x10).
adcrec=$54 ' WRITE TO THE SETUP REGISTER. SET SELF-CALIBRATION MODE, GAIN TO 4, UNIPOLAR MODE, BUFFERED MODE.
' BEGIN SELF-CALIBRATION/CONVERSION BY CLEARING FSYNC.(0x44)
gosub mxsend
gosub adcrdy
'adcsend=$8
'GOSUB adread
return
mxsend: 
shiftout SI, SCK, 5, [adcsend\8] ' adcsend command to communication register
shiftout SI, SCK, 5, [adcrec\8] ' adcsend value to the selecte register
return

adcrdy:
While ADCready = 1:Wend 'wait for valid data to be adceived. Er angivet under self calibration mode.
' Note that after the self calibration, AD7705 start free conversion cycle.
Return
' ----------------------------------------------------------------------------
' Get Battery level Value A to D routine
' ----------------------------------------------------------------------------
 
                                 '  usable battery 2.7-5.4vdc (4xAAbats)
GetBatValue:                     'potential divider of 2x 5m6 res accross bat
        Total = 0                ' 0-1024 bits for 0-10.00 vin (o/p max650)
        For z = 1 to 64             'Average of 64 readings to reduce noise
            ADCIN 0, value1
            Total = Total + value1
        next
        TXbat = Total >> 6                ' Same as divide by 64
        TXbat =  TXbat-722                'usable range 300 bits
        TXbat = TXbat/3 
        if Txbat < 1 then Txbat = 0
        if Txbat > 100  then Txbat = 100
        if TXbat < 20  then 
        freqout portc.2, 500,5 'gosub Battlow     '10.0 volt level         '1024 bits for 12.9vdc usable range 
        else
        freqout portc.2,10,10
        endif 
    return
        
   GetRange:
   REAd 6,Range.byte0 :read 7,Range.byte1 
   if range < 1000 then range = 2000
   if range > 4096 then range = 2000  
   goto Main
 
' ----------------------------------------------------------------------------
' Auto calibrate
' ----------------------------------------------------------------------------
 
 calibrate: 
 portc.4 = 0
 PAUSE 5000
 gosub getadvalue
 if ADCvalue > 800 then 
 goto GetRange
 else 
 gosub GetAdValue
 Loadx = ADCvalue
 portc.4 = 1: pause 5000  ' Apply calibration signal & wait 5 sec's
 gosub GetAdValue
 Loady = ADCvalue
 portc.4 = 0             ' Switch off  calibration signal 
 Loady = abs (Loady - Loadx)
 gosub calspan 
 Return
 endif   
' ----------------------------------------------------------------------------
' Calspan
' ----------------------------------------------------------------------------
 
 calspan: 
 if (calval < 650 ) or ( calval > 999) then calval = 750
 x = Calval * ScaleBits
 Range = div32 Loady
 peak = 0
 write 6,Range.byte0 :write 7,Range.byte1
 return

[Acetronics2]

Hi,

1) I do not think you have to modify the OSCTUNE register ...

2) Place PAUSE 1000 AFTER " DEFINE OSC ..."

3) You can use PLL x 4 Setting, with a 10 to 16 Mhz Xtal ... will give 40 to 64 Mhz Osc speed. Should be enough ...
40 and 48 Mhz are commonly admitted ... 64 is experimental ... but works fine !!!

You first have to change your 18F2525.inc file ( in the PBP/ INC folder ) for :

;****************************************************************
;*  18F2525.INC                                                 *
;*                                                              *
;*  By        : Leonard Zerman, Jeff Schmoyer                   *
;*  Notice    : Copyright (c) 2008 microEngineering Labs, Inc.  *
;*              All Rights Reserved                             *
;*  Date      : 09/15/08                                        *
;*  Version   : 2.60                                            *
;*  Notes     :                                                 *
;****************************************************************
        NOLIST
    ifdef PM_USED
        LIST
        "Error: PM does not support this device.  Use MPASM."
        NOLIST
    else
        LIST
        LIST p = 18F2525, r = dec, w = -311, w = -230, f = inhx32
        INCLUDE "P18F2525.INC" ; MPASM  Header
        ;__CONFIG    _CONFIG1H, _OSC_HS_1H & _FCMEN_OFF_1H & _IESO_OFF_1H
        ;__CONFIG    _CONFIG2H, _WDT_ON_2H & _WDTPS_512_2H
        ;__CONFIG    _CONFIG3H, _CCP2MX_PORTC_3H & _PBADEN_OFF_3H 
_LPT1OSC_OFF_3H & _MCLRE_ON_3H
        ;__CONFIG    _CONFIG4L,  _STVREN_ON_4L & _LVP_OFF_4L & _XINST_OFF_4L
  Messg " Think to WRITE the correct  CONFIGURATION ... "
  Messg " Think to WRITE the correct  CONFIGURATION ... "
  Messg " Think to WRITE the correct  CONFIGURATION ... "
        NOLIST
    endif
        LIST
EEPROM_START EQU 0F00000h
BLOCK_SIZE EQU 64

THEN

add to the top of your code, just past the Header :

'*****************************************************************************
'Config processeur
'*****************************************************************************
@   __CONFIG    _CONFIG1H, _IESO_OFF_1H & _OSC_HSPLL_1H & _FCMEN_OFF_1H
@   __CONFIG    _CONFIG2L, _BOREN_OFF_2L & _PWRT_ON_2L
@   __CONFIG    _CONFIG2H, _WDT_OFF_2H & _WDTPS_128_2H
@   __CONFIG    _CONFIG3H, _MCLRE_ON_3H & _LPT1OSC_OFF_3H & _PBADEN_OFF_3H & _CCP2MX_PORTBE_3H
@   __CONFIG    _CONFIG4L, _STVREN_OFF_4L & _LVP_OFF_4L & _DEBUG_OFF_4L & _XINST_OFF_4L
@   __CONFIG    _CONFIG5L, _CP0_OFF_5L & _CP1_OFF_5L
@   __CONFIG    _CONFIG5H, _CPB_OFF_5H & _CPD_OFF_5H
@   __CONFIG    _CONFIG6L, _WRT0_OFF_6L & _WRT1_OFF_6L
@   __CONFIG    _CONFIG6H, _WRTB_OFF_6H & _WRTC_OFF_6H & _WRTD_OFF_6H 
@   __CONFIG    _CONFIG7L, _EBTR0_OFF_7L & _EBTR1_OFF_7L
@   __CONFIG    _CONFIG7H, _EBTRB_OFF_7H

You'll have to use " DEFINE OSC xx " Where XX will be 4 x your choosen Xtal frequency.

an also think to modify Serin2/Serout2 to match your Osc speed ...

after that ... check your program flow ... if not enough !!!

Alain

[J_norrie]

Hi Alain, Thanks for your help. It turns out that the main reason I cant get it to go faster seems to be the time it needs to carry out the analog to digital conversions if I took out the get ADCloop and the getbatlevel it goes like the clappers. If I reintroduce either it slows right down. I have all the averaging loops for both and the signals are still steady and the speed went up to 40 samples per second. I then reduced the times it went to get the battary level to every 150 samples. I am now getting 80 samples per second which is quite acceptable. It didnt seem to make a differance changing the clock to 40mHz using HSPLL and a 10Mhz crystal, but I have left it at that.

Again many thanks Alain for your help. Its great knowing that this forum is here with such helpful people.

cheers and many thanks John

[tenaja]

I realize you have reached your target, but here are some tips to help in the future.

The shiftin/shiftout commands are dreadfully, painfully, pathetically slow. And also very slow. If you use an onboard a/d, or at the least, use the hardware SPI module to talk to an external a/d, you will gain a huge amount of thru-put... On the order of 10x faster, if the off-chip a/d can handle it.

Another trick is to send the data as raw values, and format it on the receiving end since it's fixed width. That will save a minimum of 30% in your case, 20% if you want to leave an alignment byte.

[Acetronics2]

Hi Alain, Thanks for your help. It turns out that the main reason I cant get it to go faster seems to be the time it needs to carry out the analog to digital conversions

Hi, John

You also could reduce Adc sampling time to 100 or 200 µs ... instead of 5 ms !

Alain