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  1. #1
    Join Date
    May 2012
    Posts
    6

    Default Problem with I2C

    Hello to everyone!

    I attempt to read temperature from a DS1621. The program is really simple, but I have a short experience programming and it doesn't work. I hope you can help me. Here is my code:
    Code:
            @__CONFIG    _CONFIG1L, _PLLDIV_5_1L & _CPUDIV_OSC1_PLL2_1L & _USBDIV_2_1L
            @__CONFIG    _CONFIG1H, _FOSC_HSPLL_HS_1H & _FCMEN_OFF_1H & _IESO_OFF_1H
            @__CONFIG    _CONFIG2L, _PWRT_OFF_2L & _BOR_ON_2L & _BORV_3_2L & _VREGEN_ON_2L
            @__CONFIG    _CONFIG2H, _WDT_ON_2H & _WDTPS_512_2H
            @__CONFIG    _CONFIG3H, _CCP2MX_ON_3H & _PBADEN_OFF_3H & _LPT1OSC_OFF_3H & _MCLRE_OFF_3H
            @__CONFIG    _CONFIG4L, _STVREN_ON_4L & _LVP_OFF_4L & _XINST_OFF_4L
    
    
    'LCD
    DEFINE LCD_DREG PORTB 
    DEFINE LCD_DBIT 4     
    DEFINE LCD_RSREG PORTB
    DEFINE LCD_RSBIT 1    
    DEFINE LCD_EREG PORTB 
    DEFINE LCD_EBIT 2     
    
    
    'I2C
    CMCON = 7
    ADCON1 = 7
    SCL VAR PORTA.0 
    SDA VAR PORTA.1
    WO var WORD
    T1 var WO.byte0
    T2 var WO.byte1
    main:
    i2cwrite SDA,SCL,%10010000 
    Pause 10
    i2cwrite SDA,SCL,$90,$AC,[0] 
    Pause 10
    i2cwrite SDA,SCL,$90,$EE 
    Pause 50
    i2cwrite SDA,SCL,$90,$AA 
    pause 10
    i2cread SDA,SCL,$91,[T1,T2]
    pause 10
    LCDout $FE,1
    LCDout $FE,1, #WO
    goto main
    I only want to show in an LCD the data from the DS1621

    Thank you!

  2. #2
    Join Date
    May 2012
    Posts
    6

    Default Re: Problem with I2C

    I updated the code with things I have learned from internet but it doesn't work yet.
    Code:
            @__CONFIG    _CONFIG1L, _PLLDIV_5_1L & _CPUDIV_OSC1_PLL2_1L & _USBDIV_2_1L
            @__CONFIG    _CONFIG1H, _FOSC_HSPLL_HS_1H & _FCMEN_OFF_1H & _IESO_OFF_1H
            @__CONFIG    _CONFIG2L, _PWRT_OFF_2L & _BOR_ON_2L & _BORV_3_2L & _VREGEN_ON_2L
            @__CONFIG    _CONFIG2H, _WDT_ON_2H & _WDTPS_512_2H
            @__CONFIG    _CONFIG3H, _CCP2MX_ON_3H & _PBADEN_OFF_3H & _LPT1OSC_OFF_3H & _MCLRE_OFF_3H
            @__CONFIG    _CONFIG4L, _STVREN_ON_4L & _LVP_OFF_4L & _XINST_OFF_4L
    
    
    'LCD
    DEFINE LCD_DREG PORTB 
    DEFINE LCD_DBIT 4     
    DEFINE LCD_RSREG PORTB
    DEFINE LCD_RSBIT 1    
    DEFINE LCD_EREG PORTB 
    DEFINE LCD_EBIT 2     
    
    
    'I2C
    CMCON = 7
    ADCON1 = 7
    SCL VAR PORTA.2	
    SDA VAR PORTA.3
    i2c_read CON 1          'R/W configuration bit (1 = read)
    i2c_write CON 0         'R/W configuration bit (0 = write)
    i2c_out VAR BYTE        'data to sent over I2C bus
    i2c_in  VAR BYTE[2]     'data received over I2C bus
    i2c_ack VAR BIT         'acknowledgement bit
    temp VAR WORD
    
    
        GOSUB Config_Register   'Set Configuration
        GOSUB Start_Convert     'Start continuous conversion
    
    
    TOP:
        PAUSE 2000
        GOSUB Read_Temp    
        i2c_in[2] = i2c_in[1] >> 3 
        temp = (i2c_in[1]*1000) 
        LCDout $FE,1,#temp
        GOTO TOP            
    
    
    Config_Register:        
        GOSUB I2C_START     
        i2c_out = %10010000                         
        GOSUB I2C_TX        
        i2c_out = $AC       
        GOSUB I2C_TX        
        i2c_out = $00       
        GOSUB I2C_TX        
        GOSUB I2C_STOP      
        RETURN
     
    Start_Convert:          
        GOSUB I2C_START
        i2c_out = %10010000 
        GOSUB I2C_TX
        i2c_out = $EE       
        GOSUB I2C_TX
        GOSUB I2C_STOP
        RETURN
     
    Read_Temp:              
        GOSUB I2C_START
        i2c_out = %10010000 
        GOSUB I2C_TX        
        i2c_out = $AA       
        GOSUB I2C_TX
        GOSUB I2C_START     
        i2c_out = %10010001 
        GOSUB I2C_TX        
        GOSUB I2C_RX        
        GOSUB I2C_STOP     
        RETURN
    
    
    I2C_START:              
        HIGH SDA
        HIGH SCL
        LOW SDA
        LOW SCL
        RETURN
     
    I2C_STOP:               
        LOW SDA
        HIGH SCL
        HIGH SDA
        PAUSE 1
        RETURN
     
    I2C_RX:                           
        SHIFTIN SDA,SCL,0,[i2c_in[0]] 
        SHIFTOUT SDA,SCL,1,[%0\1]     
        SHIFTIN SDA,SCL,0,[i2c_in[1]] 
        SHIFTOUT SDA,SCL,1,[%1\1]     
        RETURN
     
    I2C_TX:                           
        SHIFTOUT SDA,SCL,1,[i2c_out]   
        SHIFTIN SDA,SCL,0,[i2c_ack\1]           
        RETURN

  3. #3
    Join Date
    May 2012
    Posts
    6

    Default Re: Problem with I2C

    Name:  Captura.PNG
Views: 459
Size:  57.5 KB
    Here you can see the circuit

  4. #4
    Join Date
    Nov 2003
    Location
    Wellton, U.S.A.
    Posts
    5,843

    Default Re: Problem with I2C

    You do not have
    DEFINE OSC XX
    in your code

    What speed is the OSC source?

    It is best to set up an LED and make it blink at a known rate before you jump into anything else to be sure of your setup.
    Dave
    Always wear safety glasses while programming.

  5. #5
    Join Date
    May 2012
    Posts
    6

    Default Re: Problem with I2C

    I set the speed and it still don't work. The configuration is good because I tested it before with a more simple circuit

  6. #6
    Join Date
    Nov 2003
    Location
    Wellton, U.S.A.
    Posts
    5,843

    Default Re: Problem with I2C

    Sorry that I did not see this before
    Try
    ADCON1 = %00001111

    You have AN0 - AN7 as analog.

    AN0 - AN4 on the 2550


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    Last edited by mackrackit; - 6th May 2012 at 16:29.
    Dave
    Always wear safety glasses while programming.

  7. #7
    Join Date
    May 2012
    Posts
    6

    Default Re: Problem with I2C

    Thank you so much for your help Mackrackit =D, but it still don't work. I don't know why because the code is not difficult, but I can't find the mistakes

  8. #8
    Join Date
    Jul 2003
    Location
    Colorado Springs
    Posts
    4,935

    Default Ds1621

    I got a good laugh out of this one.
    When the code doesn't work, rewrite PBP's I2C commands ...

    Try this ...
    Code:
    DEFINE OSC 48
    CLEAR
    
    #config
        __CONFIG    _CONFIG1L, _PLLDIV_5_1L & _CPUDIV_OSC1_PLL2_1L & _USBDIV_2_1L
        __CONFIG    _CONFIG1H, _FOSC_HSPLL_HS_1H & _FCMEN_OFF_1H & _IESO_OFF_1H
        __CONFIG    _CONFIG2L, _PWRT_OFF_2L & _BOR_ON_2L & _BORV_3_2L & _VREGEN_ON_2L
        __CONFIG    _CONFIG2H, _WDT_ON_2H & _WDTPS_512_2H
        __CONFIG    _CONFIG3H, _CCP2MX_ON_3H & _PBADEN_OFF_3H & _LPT1OSC_OFF_3H & _MCLRE_OFF_3H
        __CONFIG    _CONFIG4L, _STVREN_ON_4L & _LVP_OFF_4L & _XINST_OFF_4L
    #endconfig
    
    ;----[LCD definitions]--------------------------------------------------------
    DEFINE LCD_DREG  PORTB                            ; LCD Data port
    DEFINE LCD_DBIT  4                                ; starting Data bit (0 or 4)
    DEFINE LCD_EREG  PORTB                            ; LCD Enable port
    DEFINE LCD_EBIT  2                                ;     Enable bit
    DEFINE LCD_RSREG PORTB                            ; LCD Register Select port
    DEFINE LCD_RSBIT 1                                ;     Register Select bit
    DEFINE LCD_BITS  4                                ; LCD bus size (4 or 8 bits)
    DEFINE LCD_LINES 2                                ; number of lines on LCD
    DEFINE LCD_COMMANDUS 2000                         ; Command delay time in us 
    DEFINE LCD_DATAUS 50                              ; Data delay time in us 
    
    SCL VAR PORTA.2                                   ; I2C Clock
    SDA VAR PORTA.3                                   ; I2C Data
    
    TempHigh    CON 28                                ; DS1621 High Temp Limit
    TempLow     CON 24                                ; DS1621 Low Temp Limit
    DS1621      CON $90                               ; DS1621 Slave Address
    ConfigReg   VAR BYTE                              
    TempC       VAR WORD
    
    ;----[Initialization]-----------------------------------------------------------
    CMCON = 7
    ADCON1 = 15
    
    I2CREAD SDA,SCL,DS1621,$AC,[ConfigReg]            ; Read the configuration
    IF ConfigReg.0 = 1 THEN                           ; if in Polling Mode?
        I2CWRITE SDA,SCL,DS1621,$AC,[0]               ; Set it to Continuous Mode
        GOSUB WaitForEE
    ENDIF
    
    I2CREAD SDA,SCL,DS1621,$A1,[TempC.LowByte]        ; Read the High Temp Limit
    IF TempC != TempHigh THEN                         ; if High limit is incorrect
        I2CWRITE SDA,SCL,DS1621,$A1,[TempHigh]        ;  Write High Limit
        GOSUB WaitForEE
    ENDIF
    
    I2CREAD SDA,SCL,DS1621,$A2,[TempC.LowByte]        ; Read the Low Temp Limit
    IF TempC != TempLow THEN                          ; if Low limit is incorrect
        I2CWRITE SDA,SCL,DS1621,$A2,[TempLow]         ;  Write Low Limit
        GOSUB WaitForEE
    ENDIF
    
    I2CWRITE SDA,SCL,DS1621,$EE,[0]                   ; Start Conversions
    
    ;----[Main Program Loop]--------------------------------------------------------
    Main:
        PAUSE 900
        I2CREAD SDA,SCL,DS1621,$AC,[ConfigReg]        ; Read the configuration
        LCDOUT $FE,$80,"CONFIG=",IBIN8 ConfigReg
                                                      ; Read the Temperature
        I2CREAD SDA,SCL,DS1621,$AA,[TempC.HighByte, TempC.LowByte]
        LCDOUT $FE,$C0,"  Temp="
        GOSUB ShowTemp
    
        I2CREAD SDA,SCL,DS1621,$A1,[TempC.HighByte, TempC.LowByte]
        LCDOUT $FE,$94,"    TH="
        GOSUB ShowTemp
        
        I2CREAD SDA,SCL,DS1621,$A2,[TempC.HighByte, TempC.LowByte]
        LCDOUT $FE,$D4,"    TL="
        GOSUB ShowTemp
        
    GOTO Main
    
    ;----[Show Temp on LCD]----------------------------------------------------------
    ShowTemp:
        LCDOUT DEC TempC.HighByte
        IF TempC.7 THEN
            LCDOUT ".5  "
        ELSE
            LCDOUT ".0  "
        ENDIF
    RETURN
    
    ;----[Wait for DS1621 EEPROM Write]----------------------------------------------
    WaitForEE:
        REPEAT                                        ; Wait for EEPROM write
            I2CREAD SDA,SCL,DS1621,$AC,[ConfigReg]
            LCDOUT $FE,$80,"CONFIG=",IBIN8 ConfigReg
        UNTIL ConfigReg.4 = 0
    RETURN
    Attached Files Attached Files
    Last edited by Darrel Taylor; - 6th May 2012 at 20:03.
    DT

  9. #9
    Join Date
    Nov 2003
    Location
    Wellton, U.S.A.
    Posts
    5,843

    Default Re: Ds1621

    Quote Originally Posted by Darrel Taylor View Post
    I got a good laugh out of this one.
    When the code doesn't work, rewrite PBP's I2C commands ...
    I do not think he was trying to rewrite the command, he was just trying to make his project work.
    As he said, he tried something found on the internet. Might have been this.
    http://www.rentron.com/PicBasic/i2c_communication.htm
    Dave
    Always wear safety glasses while programming.

  10. #10
    Join Date
    May 2012
    Posts
    6

    Default Re: Problem with I2C

    Thank you so much for your help!. As I said I have a really short experience programming so I have a lot of mistakes...

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