Bsoch BMP085

[ohararp]

Well, after taking way too much time working with the code I finally ported code from both PBP and Arduino to PDS. Code is below!


Good Reference links:
http://www.sparkfun.com/products/9694
http://www.sparkfun.com/tutorials/253
http://www.picbasic.co.uk/forum/showthread.php?t=13081&
http://www.picbasic.co.uk/forum/showthread.php?t=13081&

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 A'****************************************************************
'*  Name    : BMP085_PDS_IMU_B.bas                              *
'*  Author  : Ryan O'Hara                                       *
'*  Notice  : Copyright (c) 2011 OHARARP LLC                    *
'*          : All Rights Reserved                               *
'*  Date    : 6/8/2011                                          *
'*  Version : 1.0                                               *
'*  Notes   : Getting this device to work was a P.I.T.A         *
'****************************************************************
Device = 18F26K22
    Xtal = 10
    All_Digital = TRUE
;-------------------------------------------------------------------------------
;**** Added by Fuse Configurator ****
; Use the Fuse Configurator plug-in to change these settings

Declare Reminders Off
@ CONFIG_REQ = 0 ; Override Compiler's configuration settings
Asm-
Config FOSC = HSMP	;EC oscillator (medium power, 4-16 MHz)
Config PLLCFG = OFF	;Oscillator used directly
Config PRICLKEN = On	;Primary clock enabled
Config FCMEN = OFF	;Fail-Safe Clock Monitor disabled
Config IESO = OFF	;Oscillator Switchover mode disabled
Config PWRTEN = OFF	;Power up timer disabled
Config BOREN = SBORDIS	;Brown-out Reset enabled in hardware only (SBOREN is disabled)
Config BORV = 190	;VBOR set to 1.90 V nominal
Config WDTEN = OFF	;Watch dog timer is always disabled. SWDTEN has no effect.
Config WDTPS = 256	;1:256
Config CCP2MX = PORTC1	;CCP2 input/output is multiplexed with RC1
Config PBADEN = OFF	;PORTB<5:0> pins are configured as digital I/O on Reset
Config CCP3MX = PORTB5	;P3A/CCP3 input/output is multiplexed with RB5
Config HFOFST = On	;HFINTOSC output and ready status are not delayed by the oscillator stable status
Config T3CMX = PORTC0	;T3CKI is on RC0
Config P2BMX = PORTB5	;P2B is on RB5
Config MCLRE = EXTMCLR	;MCLR pin enabled, RE3 input pin disabled
Config STVREN = On	;Stack full/underflow will cause Reset
Config LVP = On	;Single-Supply ICSP enabled if MCLRE is also 1
Config XINST = OFF	;Instruction set extension and Indexed Addressing mode disabled (Legacy mode)
Config Debug = OFF	;Disabled
Config CP0 = OFF	;Block 0 (000800-003FFFh) not code-protected
Config CP1 = OFF	;Block 1 (004000-007FFFh) not code-protected
Config CP2 = OFF	;Block 2 (008000-00BFFFh) not code-protected
Config CP3 = OFF	;Block 3 (00C000-00FFFFh) not code-protected
Config CPB = OFF	;Boot block (000000-0007FFh) not code-protected
Config CPD = OFF	;Data EEPROM not code-protected
Config WRT0 = OFF	;Block 0 (000800-003FFFh) not write-protected
Config WRT1 = OFF	;Block 1 (004000-007FFFh) not write-protected
Config WRT2 = OFF	;Block 2 (008000-00BFFFh) not write-protected
Config WRT3 = OFF	;Block 3 (00C000-00FFFFh) not write-protected
Config WRTC = OFF	;Configuration registers (300000-3000FFh) not write-protected
Config WRTB = OFF	;Boot Block (000000-0007FFh) not write-protected
Config WRTD = OFF	;Data EEPROM not write-protected
Config EBTR0 = OFF	;Block 0 (000800-003FFFh) not protected from table reads executed in other blocks
Config EBTR1 = OFF	;Block 1 (004000-007FFFh) not protected from table reads executed in other blocks
Config EBTR2 = OFF	;Block 2 (008000-00BFFFh) not protected from table reads executed in other blocks
Config EBTR3 = OFF	;Block 3 (00C000-00FFFFh) not protected from table reads executed in other blocks
Config EBTRB = OFF	;Boot Block (000000-0007FFh) not protected from table reads executed in other blocks
Endasm-
Declare Reminders On

;**** End of Fuse Configurator Settings ****
;-------------------------------------------------------------------------------

       
' Software Defines (variables and pins)
    Dim Upres       As Dword            'uncompensated temp reading
    Dim wUpres      As Word
    Dim Cpres       As Dword            'compensated pressure
    Dim Cpres2      As Dword            'temp variable
    Dim CpresHg     As Float            'Pres in inHg
    Dim Utemp       As Dword            'uncompensated pressure reading
    Dim wUtemp      As Word             'uncompensated pressure reading
    Dim CTemp       As Float            'Compensated (real) temperature DegC
    Dim CtempF      As Float            'Compensated (real) temperature DegF

    Dim i2c_Reg     As Byte             'variable for target i2c register address
    Dim idx         As Byte

    Symbol SCL    =  PORTC.3       ' I2C clock pin 
    Symbol SDA    =  PORTC.4       ' I2C data pin

    Symbol OSS    =  3          'This value is the Over Sampling Setting for the BMP085
                                 '0 = minimum, 3 = maximum. Also change value in Read_pres if you alter OSS

Dim wAC1h As Byte
Dim wAC1l As Byte

    Dim wAC1 As Word
    Dim wAC2 As Word
    Dim wAC3 As Word
    Dim wAC4 As Word
    Dim wAC5 As Word
    Dim wAC6 As Word
    Dim wB1 As Word
    Dim wB2 As Word
    Dim wMB As Word
    Dim wMC As Word
    Dim wMD As Word
   
    Dim AC1 As Dword
    Dim AC2 As Dword
    Dim AC3 As Dword
    Dim AC4 As Dword
    Dim AC5 As Dword
    Dim AC6 As Dword
    Dim B1 As Dword
    Dim B2 As Dword
    Dim MB As Dword
    Dim MC As Dword
    Dim MD As Dword

    Dim X1 As Dword    
    Dim X2 As Dword
    Dim X3 As Dword
    Dim B3 As Dword
    Dim B4 As Dword
    Dim B5 As Dword
    Dim B6 As Dword
    Dim B7 As Dword
 
                          
'Main loop -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Main:  
        GoSub Read_cal       
        GoSub Read_temp                        'get Temp via I2C
        GoSub Read_pres                         
        GoSub Cal_temp
        GoSub Cal_pres
 
        SerOut PORTB.7,84,["UT=",SDec Utemp," ",13,10]
        SerOut PORTB.7,84,["UP=",SDec Upres," ",13,10]
        SerOut PORTB.7,84,["TempC = ",SDec CTemp," TempF = ",SDec CtempF,13,10]
        SerOut PORTB.7,84,["hPa   = ",SDec Cpres," inHg  = ",SDec CpresHg,13,10,13,10]
GoTo Main
'SUBROUTINES -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Cal_temp:
'Calculate temperature in 1/10ths of Deg C  from lUTemp     ' Note 2^15 = 32768 Dec or $8000
    X1 = (Utemp - AC6) * AC5
    X1 = X1 >> 15
    X2 = MC << 11
    X2 = X2 / (X1 + MD)           
    B5 =  X1 + X2                 
    CTemp = (B5 + 8) / 160        
    CtempF = CTemp * 9 / 5
    CtempF = CtempF + 32
Return

Cal_pres:         
'Calculate pressure in Pascals from uncompensated pressure dUpres (1/100th's of hPa's)        
    B6 = B5 - 4000
    'SerOut PORTB.7,84,["B6=",SDec B6,13,10]
    X1 = B2 * B6 * B6
    'SerOut PORTB.7,84,["X1=",SDec X1,13,10]
    X1 = (X1 / $1000) / $800 
    'SerOut PORTB.7,84,["X1=",SDec X1,13,10]
    X2 = (AC2 * B6) / $800
    'SerOut PORTB.7,84,["X2=",SDec X2,13,10]    
    X3 = X1 + X2
    'SerOut PORTB.7,84,["X3=",SDec X3,13,10]
    B3 = (AC1 * 4 + X3)
    'SerOut PORTB.7,84,["B3=",SDec B3,13,10]
    B3 = (B3 << OSS) + 2 
    'SerOut PORTB.7,84,["B3=",SDec B3,13,10]
    B3 = B3 >> 2     'OSS = Over Sampling constant set above  
    'SerOut PORTB.7,84,["B3=",SDec B3,13,10]

    X1 = (AC3 * B6) / $2000
    'SerOut PORTB.7,84,["X1=",SDec X1,13,10]
    X2 = B1 * B6 * B6
    'SerOut PORTB.7,84,["X2=",SDec X2,13,10]
    X2 = (X2 / $1000) / $10000
    'SerOut PORTB.7,84,["X2=",SDec X2,13,10]
    X3 = X1 + X2 + 2
    'SerOut PORTB.7,84,["X3=",SDec X3,13,10]
    X3 = X3 / 4
    'SerOut PORTB.7,84,["X3=",SDec X3,13,10]
    B4 = AC4 * (X3 + 32768)
    'SerOut PORTB.7,84,["B4=",SDec B4,13,10]
    B4 = B4 / $8000        
    'SerOut PORTB.7,84,["B4=",SDec B4,13,10]

    B7 = Upres - B3
    'SerOut PORTB.7,84,["B7=",SDec B7,13,10]
    B7 = B7 * (50000 >> OSS)  'OSS = Over Sampling constant set above
    'SerOut PORTB.7,84,["B7=",SDec B7,13,10]

    If B7 < $80000000 Then 'branch if value is above or below range
        Cpres = (B7 * 2) / B4
        Else
        Cpres = (B7 / B4) * 2
    EndIf
    'SerOut PORTB.7,84,["Cpres=",SDec Cpres,13,10]

    X1 = Cpres /256
    'SerOut PORTB.7,84,["X1=",SDec X1,13,10]
    X1 = X1 * Cpres /256
    'SerOut PORTB.7,84,["X1=",SDec X1,13,10]
    X1 = (X1 * 3038) >> 16
    'SerOut PORTB.7,84,["X1=",SDec X1,13,10]
    X2 = (7357 * Cpres) >> 16
    X2 = -X2
    'SerOut PORTB.7,84,["X2=",SDec X2,13,10]
    Cpres2 = X1 + X2 + 3791
    'SerOut PORTB.7,84,["Cpres2=",SDec Cpres2,13,10]
    Cpres2 = Cpres2 / 16
    'SerOut PORTB.7,84,["Cpres2=",SDec Cpres2,13,10]
    Cpres = Cpres + Cpres2     'Cpres is the true pressure in Pa
    'SerOut PORTB.7,84,["Cpres=",SDec Cpres,13,10]
    CpresHg = Cpres / 3386.0  'Pascals to inHg
Return

Read_cal:
    i2c_Reg =$AA  'Start address of the BMP085 calibration data
    I2CIn SDA,SCL,$EF,i2c_Reg, [wAC1,wAC2,wAC3,wAC4,wAC5,wAC6,wB1,wB2,wMB,wMC,wMD]  'Read 11 words out of sensor MSB then LSB

    AC1 = (wAC1.HighByte<<8) + wAC1.LowByte  
    AC2 = (wAC2.HighByte<<8) + wAC2.LowByte  
    AC2 = AC2-65536
    AC3 = (wAC3.HighByte<<8) + wAC3.LowByte  
    AC3 = AC3-65536
    AC4 = (wAC4.HighByte<<8) + wAC4.LowByte         
    AC5 = (wAC5.HighByte<<8) + wAC5.LowByte
    AC6 = (wAC6.HighByte<<8) + wAC6.LowByte
    B1 = (wB1.HighByte<<8) + wB1.LowByte
    B2 = (wB2.HighByte<<8) + wB2.LowByte
    MB = (wMB.HighByte<<8) + wMB.LowByte
    MB = MB - 65536
    MC = (wMC.HighByte<<8) + wMC.LowByte
    MC = MC - 65536
    MD = (wMD.HighByte<<8) + wMD.LowByte

    SerOut PORTB.7,84,["AC1=",SDec AC1,13,10]
    SerOut PORTB.7,84,["AC2=",SDec AC2,13,10]
    SerOut PORTB.7,84,["AC3=",SDec AC3,13,10]
    SerOut PORTB.7,84,["AC4=",SDec AC4,13,10]
    SerOut PORTB.7,84,["AC5=",SDec AC5,13,10]
    SerOut PORTB.7,84,["AC6=",SDec AC6,13,10]

    SerOut PORTB.7,84,["B1=",SDec B1,13,10]
    SerOut PORTB.7,84,["B2=",SDec B2,13,10]
    SerOut PORTB.7,84,["MB=",SDec MB,13,10]
    SerOut PORTB.7,84,["MC=",SDec MC,13,10]
    SerOut PORTB.7,84,["MD=",SDec MD,13,10,13,10]
 
Return
    
Read_pres: 
    i2c_Reg = $F4                               '$F4 is the control register address
    I2COut SDA,SCL,$EE,i2c_Reg,[$F4]            'Write $34+(oss << 6) to set pressure conversion 
    DelayMS 30                                  'Delay 10ms after each write (30mS for HiRes results (oss=3))
    i2c_Reg = $F6                               '$F6 is the result register MSB
    I2CIn SDA,SCL,$EF,i2c_Reg,[Upres]           'Read pressure MSB, LSB, XLSB, $F9 ($F9 not actually wanted).
    Upres = Upres >> (16 - OSS)                 'remove $F9 from result (>>8), and left shift result back to 16 to 19 Bits (OSS value dependant)
    
Return                                          'we only want top 19bits of the result.
              
Read_temp:
    i2c_Reg = $F4                               '$F4 is the control register address
    I2COut SDA,SCL,$EE,i2c_Reg,[$2E]            'Write $2E to set temperature conversion 
    DelayMS 10                                  'Delay 10ms after each write
    i2c_Reg = $F6                               '$F6 is the result register MSB
    I2CIn SDA,SCL,$EF,i2c_Reg,[wUtemp]          'Read temperature MSB, LSB.
    'SerOut PORTB.7,84,["wut=",Hex wUtemp.HighByte,32,Hex wUtemp.LowByte,13,10]
    Utemp = (wUtemp.HighByte<<8) +  wUtemp.LowByte
    'SerOut PORTB.7,84,["ut=",Hex Utemp.Byte3,32,Hex Utemp.Byte2,32,Hex Utemp.Byte1,32,Hex Utemp.Byte0,32,13,10]
 Return

[John Drew]

Looks good Ryan. How about writing it up for the WIKI?
John

[ta1dr]

Hi Ryan

Good article
thanks for share

ahmet

[ohararp]

Thanks for the input. I am in the process of incorporating code for 3 other sensors for an IMU board. I'll add these to other threads and try and do a full writeup of the entire board in the wiki. Thanks for the suggestion on that John!

[John Drew]

Excellent Ryan, look forward to reading it. If you have any trouble publishing the article on the Wiki send me a PM and I'll do whatever is necessary to help. Lester is working on permissions at present and there is a small possibility you may have trouble with the final step of making the article visible to everyone.
Cheers
John

[fdapport]

try to use this code, read correct the temperature but I have not correct value of the pressure, all get wrong from the I2C pressure reader I2C code, look like that I read BIG value. Could somabody help me to read this sensor, Thanks,

[Tim]

What compiler are you using?

[fdapport]

I found the error:
I made a new variable like

DIM wOSS as Byte

and change the calculation;

wOSS=16-OSS
Upres = Upres >> wOSS

The sentence Upres = Upres >> (16 - OSS) give to me wrong calculation


and the second change is:
B5 = X1 + X2 + 8
CTemp = B5/160

the sentence
'CTemp = (B5 + 8) / 16 give back wrong calculation.

with this changes it work well.