How can I adjust in USBDemo A/D converter from 8 to 10 Bit resolution?


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  1. #1
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    Default How can I adjust in USBDemo A/D converter from 8 to 10 Bit resolution?

    Hi all,
    Iím beginner and I tried modified A/D converter of USBDemo from 8 to 10 Bits, but does not work. I insert definition for 10 Bits resolution, but output value is still 8 Bits.
    How can I adjust in USBDemo A/D converter from 8 to 10 Bit resolution?

    Thanks, Kuba230


    ' USBDemo
    ' =======
    '
    ' File name : USBDemo.pbp
    ' Company : Mister E
    ' Programmer : Steve Monfette
    ' Date : December 30,2006
    ' Device : PIC18F4550 & 4MHZ crystal
    '
    '
    ' Short and sweet demo to send and read from USB bus.
    '
    ' Hardware:
    ' ---------
    ' 4 Push Buttons on PORTA<5:2> with pull-down resistors
    ' 2 Trim pot on PORTA<1:0>
    ' 8 LEDs attach between PORTB and GND
    ' 2 LEDs attach to CCP<2:1> pins
    ' 4 MHZ crystal & all the usual USB stuff
    '
    '
    ' Software:
    ' ---------
    ' A ready to run PC interface is also available, it's VB6 source code as well
    '
    ' Enjoy!
    '
    '
    ' Pic Configuration
    ' =================
    asm
    __CONFIG _CONFIG1L, _PLLDIV_1_1L & _CPUDIV_OSC1_PLL2_1L & _USBDIV_2_1L
    ; ; ; USB clock source comes from the 96 MHz PLL divided by 2
    ; ; [OSC1/OSC2 Src: /1][96 MHz PLL Src: /2]
    ; No prescale (4 MHz oscillator input drives PLL directly)


    __CONFIG _CONFIG1H, _FOSC_XTPLL_XT_1H & _FCMEN_OFF_1H & _IESO_OFF_1H
    ; ; ; Oscillator Switchover mode disabled
    ; ; Fail-Safe Clock Monitor disabled
    ; XT oscillator, PLL enabled, XT used by USB
    __CONFIG _CONFIG2L, _PWRT_ON_2L & _BOR_ON_2L & _BORV_2_2L & _VREGEN_ON_2L
    __CONFIG _CONFIG2H, _WDT_OFF_2H
    __CONFIG _CONFIG3H, _MCLRE_ON_3H & _LPT1OSC_OFF_3H & _PBADEN_OFF_3H & _CCP2MX_ON_3H
    __CONFIG _CONFIG4L, _STVREN_ON_4L & _LVP_OFF_4L & _ICPRT_OFF_4L & _XINST_OFF_4L & _DEBUG_OFF_4L
    endasm
    DEFINE OSC 48

    Define ADC_BITS 10 ' Set number of bits in result
    Define ADC_CLOCK 3 ' Set clock source (3=rc)
    Define ADC_SAMPLEUS 20 ' puvodni (50) Set sampling time in uS

  2. #2
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    Default

    There are 2 parts to Steve's USBdemo.

    The PicBasic Pro program for the PIC, and a visual basic program for the PC.
    It would have to be changed on both ends.

    I can show you how to change it on the PIC side. But I don't do Visual Basic.
    <br>
    DT

  3. #3
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    Default How can I adjust in USBDemo A/D converter

    If you show me how to change it on the PIC side, it's enough. For Visual Basic I will find way to change it.

    Thanks,
    Kuba230


    USBDemo
    ' =======
    ' File name : USBDemo.pbp
    ' Company : Mister E
    ' Programmer : Steve Monfette
    ' Date : December 30,2006
    ' Device : PIC18F4550 & 4MHZ crystal
    '
    ' Short and sweet demo to send and read from USB bus.
    '
    ' Hardware:
    ' ---------
    ' 4 Push Buttons on PORTA<5:2> with pull-down resistors
    ' 2 Trim pot on PORTA<1:0>
    ' 8 LEDs attach between PORTB and GND
    ' 2 LEDs attach to CCP<2:1> pins
    ' 4 MHZ crystal & all the usual USB stuff

    ' Software:
    ' ---------
    ' A ready to run PC interface is also available, it's VB6 source code as well
    '
    ' Enjoy!
    '
    ' Pic Configuration
    ' =================
    asm
    __CONFIG _CONFIG1L, _PLLDIV_1_1L & _CPUDIV_OSC1_PLL2_1L & _USBDIV_2_1L
    ; ; ; USB clock source comes from the 96 MHz PLL divided by 2
    ; ; [OSC1/OSC2 Src: /1][96 MHz PLL Src: /2]
    ; No prescale (4 MHz oscillator input drives PLL directly)


    __CONFIG _CONFIG1H, _FOSC_XTPLL_XT_1H & _FCMEN_OFF_1H & _IESO_OFF_1H
    ; ; ; Oscillator Switchover mode disabled
    ; ; Fail-Safe Clock Monitor disabled
    ; XT oscillator, PLL enabled, XT used by USB
    __CONFIG _CONFIG2L, _PWRT_ON_2L & _BOR_ON_2L & _BORV_2_2L & _VREGEN_ON_2L
    __CONFIG _CONFIG2H, _WDT_OFF_2H
    __CONFIG _CONFIG3H, _MCLRE_ON_3H & _LPT1OSC_OFF_3H & _PBADEN_OFF_3H & _CCP2MX_ON_3H
    __CONFIG _CONFIG4L, _STVREN_ON_4L & _LVP_OFF_4L & _ICPRT_OFF_4L & _XINST_OFF_4L & _DEBUG_OFF_4L
    endasm
    DEFINE OSC 48

    Define ADC_BITS 10 ' Set number of bits in result
    Define ADC_CLOCK 3 ' Set clock source (3=rc)
    Define ADC_SAMPLEUS 20 ' puvodni (50) Set sampling time in uS

    ' Hardware configuration
    ' ======================
    '
    ' I/O and PORTs
    ' -------------
    PORTB = 0
    PORTC = 0
    PORTD = 0
    PORTE = 0
    TRISB = 0
    TRISC = 0
    TRISA = $FF
    TRISD = 0
    TRISE = 0
    '
    ' A/D converter
    ' -------------
    ADCON0 = %00000001 ' A/D converter on, CH0 selected
    ADCON1 = %00001101 ' AN<1:0> Analog, other digital
    ADCON2 = %10010110 ' FOSC/64, 4 TAD, right justified
    '
    ' CCP/PWM
    ' -------
    CCP1CON = %00001100 ' CCP1, PWM mode
    CCP2CON = %00001100 ' CCP2, PWM mode
    PR2 = 249 ' 12khz PWM Freq
    T2CON = %00000101 ' TMR2 on, prescaler 1:4
    '
    ' USB module
    ' ----------
    UCFG var byte EXT ' include UCFG register... Yeah Melabs didn't (
    ucfg = %00010100 ' enable internal USB pull-up, Full speed USB

    '
    ' Interrupt definition
    ' ====================
    ' TMR0 interrupt used to keep USB connection alive
    ' by sending USBSERVICE at each 100uSec or so.
    INTCON = %10100000 ' Enable global and TMR0 interrupts
    T0CON = %10000000 ' TMR0, CLK internal, prescaler 1:2, T0ON

    '
    ' Variables & constants definition
    ' ================================
    USBBufferSizeTX con 8 ' input
    USBBufferSizeRX con 8 ' output
    USBBufferCount Var Byte '
    USBBufferIn var byte[8] ' store incomming USB data
    USBBufferOut Var Byte[8] ' store outgoing USB data
    DataToSend var byte[8] ' store ADCs & pushButton data to send to USB
    String1 var byte[8] ' hold 'USB DEMO' string
    string1[0]="U"
    string1[1]="S"
    string1[2]="B"
    string1[3]=" "
    string1[4]="D"
    string1[5]="E"
    string1[6]="M"
    string1[7]="O"

    @ADRead = ADRESL ; use to read both ADCs register in one shot
    ADRead VAR WORD EXT ' make it available to use in PBP

    '
    @Duty1=_USBBufferIn+1 ; use to read both Duty bytes from specifics
    @Duty2=_USBBufferIn+3 ; USBBufferIn locations in one shot
    Duty1 var word EXT ' make them available
    Duty2 var word EXT ' to use in PBP

    '
    ' Constants definition
    ' ====================
    TMR0IF VAR INTCON.2 ' TMR0 overflow int flag
    TMR0ON VAR T0CON.7 ' TMR0 on/off bit
    TMR0IE VAR INTCON.5 ' TMR0 interrupt enable/disable bit
    GoDone var ADCON0.1 ' ADC conversion

    '
    ' Macro(s) definition
    ' ===================
    goto SwHwInit ' skip macros
    asm
    Reload_TMR0 macro
    ; Use to stop, reload, clear overflow flag and restart TMR0
    BCF _TMR0ON ; stop timer
    MOVE?CW d'65000',TMR0L ; reload for timebase ~100uSec
    BCF _TMR0IF ; clear overflow flag
    BSF _TMR0ON ; start timer
    ENDM

    SendUSB macro array
    ; Use to Copy an specific array to USBBufferOut AND send it
    ; to USB bus
    variable i=0
    while i<8
    MOVE?BB (array+i),(_USBBufferOut+i)
    i+=1
    endw
    L?CALL _DoUSBOut
    endm
    endasm

    '
    ' Software/Hardware initialisation
    ' ================================
    SwHwInit:
    pause 500 ' Settle delay
    usbinit ' initialise USB
    @ Reload_TMR0 ; Reload timer0
    ON INTERRUPT GOTO DoUSBService

    '
    ' Main program start
    ' ==================
    Start:
    ' Here we will check the status of push buttons on PORTA<5:2>
    ' do adc conversion on AN0 and AN1 and send everything to
    ' the USB bus
    '
    ' DataToSend[0&1]: AN0, AN1 8 bits ADC results
    ' DataToSend[5:2]: PORTA<5:2> status
    ' ------------------------------------------------------------
    '
    ' Look if there's any push button pressed, if so, send String1
    ' to USB bus
    ' ------------------------------------------------------------
    if (PORTA>>2)!=0 then
    @ SendUSB _String1
    endif
    '
    ' Do ADC conversion and save it to specific DataToSend array
    ' ----------------------------------------------------------
    ADCON0.2=ADCON0.2 ^ 1 ' Switch between AN0 & AN1
    PAUSEUS 10 ' arbitrary SamplingTime
    GODONE=1 ' start conversion
    WHILE GODONE : WEND ' wait 'till finish
    DATATOSEND[ADCON0.2]=(ADREAD>>2) ' save it to DataToSend array
    '
    ' Read pushbutton status and save it to DataToSend array
    ' ------------------------------------------------------
    datatosend[2] = PORTA.2
    datatosend[3] = PORTA.3
    datatosend[4] = PORTA.4
    datatosend[5] = PORTA.5
    datatosend[6] = 0
    datatosend[7] = 0
    '
    ' Send data to USB bus
    ' --------------------
    @ SendUSB _DataToSend
    '
    ' Check if there's any incomming data
    ' -----------------------------------
    gosub dousbin
    '
    ' Redo from start
    ' ---------------
    goto start
    '
    ' Subroutines area
    ' ================
    '
    DoUSBIn:
    '
    ' Check and receive data from the USB bus
    ' =======================================
    ' USBBufferIn[0] : PORTB led status
    ' USBBufferIn[1&2]: CCP1 PWM duty cycle LSB first (Duty1)
    ' USBBufferIn[3&4]: CCP2 PWM duty cycle LSB First (Duty2)
    tmr0ie = 0 ' disbale TMR0 int
    USBBufferCount = USBBufferSizeRX ' RX buffer size
    USBService ' keep connection alive
    USBIn 1, USBBufferin, USBBufferCount, Timeout ' read data, if available
    Timeout: '
    @ Reload_TMR0
    tmr0ie = 1 ' re-enable TMR0 int
    PORTB = USBBUFFERIN[0] ' output to PORTB

    CCP1CON.5=DUTY1.1 ' load CCP1 duty value
    CCP1CON.4=DUTY1.0 ' with Duty1
    CCPR1L=DUTY1>>2 '

    CCP2CON.5=DUTY2.1 ' load CCP2 duty value
    CCP2CON.4=DUTY2.0 ' with Duty2
    CCPR2L=DUTY2>>2 '
    return
    '
    '
    DoUSBOut:
    '
    ' Send data to the USB bus & Wait for USB interface to attach
    ' ================================================== =========
    TMR0IE = 0 ' Disable TMR0 interrupt
    WaitPC: '
    USBBufferCount = USBBufferSizeTX ' TX buffer size
    USBService ' keep connection alive
    USBOut 1, USBBufferOut, USBBufferCount, Waitpc ' if bus available, transmit data
    @ Reload_TMR0
    tmr0ie=1 ' Re-Enable TMR0 interrupt
    return

    DISABLE
    DoUSBService:
    usbservice ' keep connection alive
    @ Reload_TMR0 ; reload timer
    RESUME ' getout of here
    ENABLE

  4. #4
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    Steve was controlling the A/D converter manually. So adding the ADC_ DEFINE's won't have any effect.

    He was also getting a bit tricky (in a good way), so this might seem a little odd too.

    Code:
        '   Do ADC conversion and save it to specific DataToSend array     
        '   ---------------------------------------------------------- 
        ADCON0.2=ADCON0.2 ^ 1               ' Switch between AN0 & AN1
        PAUSEUS 10                          ' arbitrary SamplingTime
        GODONE=1                            ' start conversion
        WHILE GODONE : WEND                 ' wait 'till finish
    ;    DATATOSEND[ADCON0.2]=(ADREAD>>2)    ' save it to DataToSend array
        DATATOSEND[ADCON0.2*2]=ADREAD.LowByte
        DATATOSEND[ADCON0.2*2+1]=ADREAD.HighByte
        '
        '   Read pushbutton status and save it to DataToSend array    
        '   ------------------------------------------------------
        datatosend[4] = PORTA.2
        datatosend[5] = PORTA.3
        datatosend[6] = PORTA.4
        datatosend[7] = PORTA.5
    ;    datatosend[6] = 0
    ;    datatosend[7] = 0
    With the above changes, the packet being sent will have AN0 in the first 2 bytes, 0 is the lowbyte.

    AN1 is in bytes 2 and 3. and the pushbutton status is moved to bytes 4-7.

    Hope you can move things easily on the VB side.

    hth,
    DT

  5. #5
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    Default How can I adjust in USBDemo A/D converter from 8 to 10 Bit resolution?

    Hi Mr. Taylor,

    I did not tray still your advice for modification of USBDemo program, because I take my holiday. When I com back, then I will try.

    Thanks,
    Kuba230

  6. #6
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    Default How can I adjust in USBDemo A/D converter from 8 to 10 Bit resolution?

    Hi Mr. Taylor,
    I made changes of USBDemo picbasic code according your advice and after compilation I obtain error messages:

    Error[113 ] c:\pbp_prog\usbdemo.asm 61 : Symbol not previously defined (ADRead)
    Error[113 ] c:\pbp_prog\usbdemo.asm 62 : Symbol not previously defined (ADRead)

    I do not know why is happen?

    Thanks,
    Kuba230

  7. #7
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    Oops, I should have compiled it first.

    Try these 2 lines instead...
    Code:
        DATATOSEND[ADCON0.2*2]=ADRESL
        DATATOSEND[ADCON0.2*2+1]=ADRESH
    <br>
    DT

  8. #8
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    Default Two 10 Bits channels in USBDemo

    Hi Mr. Taylor,
    I did those changes to display 10 Bits value in Visual Basic program for USBDemo, it works perfectly, but only for one channel, AN0. What I have to change in picbasic USBDemo program to obtain two 10 Bits channels, AN0 and AN1?

    ;incomming ADC reading and PORTA status
    ----------------------------------------

    ;pAN0.Value = BufferIn(1) ' Display ADC results to the progress bars
    pAN0.Value = Val(BufferIn(1)) + Val(BufferIn(2)) * 256 'Display ADC for AN0
    ;pAN1.Value = BufferIn(2) ' Display ADC results to the progress bars

    '
    ;lValAN0.Text = Val(BufferIn(1)) ' Display Progress bars Values
    lValAN0.Text = Val(BufferIn(1)) + (Val(BufferIn(2)) * 256 'Display ADC for AN0
    ;lValAN1.Text = Val(BufferIn(2)) ' Display Progress bars Values

    Note:
    Also is necessary to change maximal value of progressbar properties pAN0 from 255 to 1023

    Thanks
    Kuba230

  9. #9
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    lValAN1.Text = Val(BufferIn(3)) + (Val(BufferIn(4)) * 256 'Display ADC for AN1
    DT

  10. #10
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    Default Two 10 Bits channels in USBDemo

    Hi Mr. Taylor,
    Everything is working very well.
    Thank you very much for your help.

    Kuba230

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