'******************************************************************
'*  Name      : gmbdae.bas                                        *
'*  Author    : Graziano GAIBA                                    *
'*  Date      : 15/05/04                                          *
'*  Versione  : 1.1                                               *
'*  Board     : GMM 876 + GMB HR84                                *
'*  Language  : PIC BASIC Standard  Ver. 1.45                     *
'*  Society   : Copyright (c) 2004 grifo(r) ITALIAN Technology    *
'*            : All Rights Reserved                               *
'*            : Tel.: +39 051 892052        Fax: +39 051 893661   *
'*            : http://www.grifo.com         http://www.grifo.it  *
'*            : sales@grifo.it   tech@grifo.it    grifo@grifo.it  *
'******************************************************************
'
' Il demo utilizza il timer 2 del Mini Modulo per generare, su CN4,
' un segnale PWM di frequenza prestabilita, con duty cycle programmabile in
' percentuale da console. Tale segnale, collegato ad una opportuna circuiteria
' integratrice (rete RC, amplificatore operazionale con capacita' su ramo di
' retroazione, ecc.) permette di ottenere un segnale analogico analogo a quello
' di un D/A. L'esecuzione del demo e' subordinata al Mini Modulo utilizzato e
' alla configurazione della linea seriale.
'
' For serial communication, the hardware serial port management code
' taken from example program Usart.bas is used, opportunely
' modified.
'
'
' *********************************************************************
' *                    Definitions and Constants                      *
' *********************************************************************
'
' PIC registers
symbol  INDF  = 0
symbol  FSR   = $04
' I/O Ports
symbol  PORTA = $05
symbol  TRISA = $85 ' bank 1
symbol  PORTB = $06
symbol  TRISB = $86 ' bank 1
symbol  PORTC = $07
symbol  TRISC = $87 ' bank 1
symbol  ADCON0 = $1F
symbol  ADCON1 = $9F ' bank 1
'
' Timer and CCP registers
symbol  TMR0  = $01
symbol  TMR1L = $0E
symbol  TMR1H = $0F
symbol  T1CON = $10
symbol  TMR2  = $11
symbol  PR2   = $92 ' bank 1
symbol  T2CON = $12
'
symbol  CCPR1L  = $15
symbol  CCPR1H  = $16
symbol  CCP1CON = $17
symbol  CCPR2L  = $1B
symbol  CCPR2H  = $1C
symbol  CCP2CON = $1D
'
symbol  OPTION_REG = $81 ' bank 1
'
symbol  PIE1 = $8C ' bank 1
'
' Registers used by hardware serial port management taken from
' demo Usart.bas del PIC Basic standard.
' USART registers
Symbol PIR1  = $0C             ' Peripheral Interrupt Flag register
Symbol RCSTA = $18             ' Reception status and control register
Symbol TXREG = $19             ' Data to send
Symbol RCREG = $1A             ' Data received
Symbol TXSTA = $98             ' Transmission status and control register
Symbol SPBRG = $99             ' Baud Rate Generator register
'
'
' *********************************************************************
' *                  Variables used by the program                    *
' *********************************************************************
'
'
' Used by USART
SYMBOL UsartST  = B0           ' USART status
SYMBOL UsartOut = B1           ' Character to send
symbol UsartIn  = B2           ' Character received

' Value to be printed
symbol Valore    = B3

' Generic use
SYMBOL i = B4
SYMBOL c = B5
symbol z = B6

' Used to input an hexadecimal value
symbol ValoreHex    = B7
symbol ValoreHexMSB = B8

' Used to initialise the Baud Rate Generator
symbol ValBRG = B9
'
'
' *********************************************************************
' *                          Main program                             *
' *********************************************************************
'
Main:
        gosub Module_init       ' Initialisation

'
' Demo delle sezioni PWM (CCP)
DemoPWM:
        for i=0 to 80
            lookup i,("Demo PWM",13,10,"CCP1 section is managed, output is pin 6 of CN4, frequency is 1.22 kHz."),usartout
            gosub charout
        next i
        gosub nlcr
        gosub nlcr
        ' Here section CCP1 is managed, section CCP2 is mostly the same.
        ' Please refer to data sheet.
        ' Set pin 24 of GMM 876 (RC2) as output
        peek trisc, B0
        bit2 = 0
        poke trisc,B0
        ' Enable section CCP 1 in PWM mode
        poke ccp1con, $0C
        ' Set 1.22 kHz of period and enable Timer 2
        poke pr2, $FF
        peek t2con, B0
        bit2 = 1
        bit1 = 1
        poke t2con, B0        
DemoPWMLoop:
        for i=0 to 38
            lookup i,("Insert duty cycle (000-3FF, 000 exit): "),usartout
            gosub charout
        next i
        valorehex = 0
        gosub inputhex3
        ' Set 10 bit of period of duty cycle:
        ' first set the two least significant bits...
        B0 = valorehex
        peek ccp1con, B1
        bit12 = bit0
        bit13 = bit1
        poke ccp1con, B1
        '...then set the remaining 8 bits
        B0 = B0 / 4
        B1 = valorehexmsb
        bit6 = bit8
        bit7 = bit9
        poke ccpr1l, B0
        if valorehexmsb <> 0 or valorehex <> 0 then demopwmloop
        ' Disable section CCP1
        poke ccp1con, 0
        ' Stop Timer 2
        peek t2con, B1
        bit2 = 0
        poke t2con, B1
    goto demopwm
end
'
'
' *********************************************************************
' *                      Fine del programma                           *
' *********************************************************************
'
'
' Initialisation of GMM 876
Module_init:
        ' Turn OFF A/D converter
        poke adcon0, 0
        ' Set Port A as digital input
        poke ADCON1, 7
        '
        ' Initialise USART for 19200 Baud
        W0 = 19200
        gosub calcolabrg_hs
        Poke SPBRG,64           ' Set baud rate to 19200
        Poke RCSTA,%10010000    ' Enable serial port and continuous reception
        Poke TXSTA,%00100100    ' Enable transmission, asynchronous mode
                                ' and high baud rate
        ' Switch back to bank 0 before exiting from asm
        'ASM
        'ENDASM
        pause 500                      
    return
'
'
' Determine the value to initialise the Rate Generator in high speed
' mode.
' Desired Baud Rate is in the variabile W0, the result, that is the
' value to write in register SPBRG, is in variable ValBRG.
' Please remark that to enable high speed mode bit 2 of register
' TXSTA (BRGH) must be set.
CalcolaBRG_HS:
        '           Fquartz
        ' ValBRG = -------- - 1
        '          16 * BR
        valbrg = 0
        
        if W0 = 9600 then val_9600_hs
        if W0 = 19200 then val_19200_hs
        if W0 = 38400 then val_38400_hs
        if W0 = 57600 then val_57600_hs
        if W0 = 115200 then val_115200_hs
        goto esci_hs
        
val_9600_hs:
        valbrg = 129
        goto esci_hs
val_19200_hs:
        valbrg = 64
        goto esci_hs
val_38400_hs:
        valbrg = 32
        goto esci_hs
val_57600_hs:
        valbrg = 21
        goto esci_hs
val_115200_hs:
        valbrg = 10
        goto esci_hs
esci_hs:
    return
'
'
' Determine the value to initialise the Rate Generator in low speed
' mode.
' Desired Baud Rate is in the variabile W0, the result, that is the
' value to write in register SPBRG, is in variable ValBRG.
' Please remark that to enable low speed mode bit 2 of register
' TXSTA (BRGH) must be reset.
CalcolaBRG_LS:
        '           Fquartz
       ' ValBRG = -------- - 1
        '          64 * BR        
        valbrg = 0
        
        if W0 = 1200 then val_1200_ls
        if W0 = 2400 then val_2400_ls
        if W0 = 9600 then val_9600_ls
        if W0 = 19200 then val_19200_ls
        if W0 = 76800 then val_76800_ls
        goto esci_hs
        
val_1200_ls:
        valbrg = 255
        goto esci_hs
val_2400_ls:
        valbrg = 129
        goto esci_hs
val_9600_ls:
        valbrg = 32
        goto esci_hs
val_19200_ls:
        valbrg = 15
        goto esci_hs
val_76800_ls:
        valbrg = 3
        goto esci_ls
esci_ls:
    return
'
'
' Prints two space characters
DueSpazi:   
        usartout = " "           ' Space
        gosub charout
        gosub charout
    return
'
'
' Transforms the value of variable Valore in hexadecimal and in
' ASCII characters then sends them to the serial port.
' Variable Valore must be in the range from 0 to 0FFh.
StampaHex:
        usartout = valore / 16
        gosub hexdecode
        gosub charout
StampaNibbleHex:
        usartout = valore & $0F
        gosub hexdecode
        gosub charout
    return
'
HexDecode:
        Lookup usartout,("0123456789ABCDEF"),usartout
    return
'
HexEncode:
        lookDown usartin,("0123456789abcdef"),usartin
    return
'
'
' Moves to a new line
NLCR:   usartout = 10            ' New Line
        gosub charout
CR:     usartout = 13            ' Carriage Return
        gosub charout
    return
'
'
' Input an hexadecimal value from 000 to FFF then return it into the
' variables ValoreHexMSB and ValoreHex.
InputHex3:
        gosub charin
        if usartin = 0 then InputHex3
        usartout = usartin
        gosub charout
        usartin = usartin | $20
        gosub hexencode
        valorehexMSB = usartin
InputHex:
        gosub charin
        if usartin = 0 then InputHex
        usartout = usartin
        gosub charout
        usartin = usartin | $20
        gosub hexencode
        valorehex = usartin * 16
InputHex2:
        gosub charin
        if usartin = 0 then InputHex2
        usartout = usartin
        gosub charout
        usartin = usartin | $20
        gosub hexencode
        valorehex = valorehex + usartin
        gosub nlcr
    return
'
'
' Prints a message that asks for a key to continue
ChiediTasto:
        for i = 0 to 25
            lookup i,("Press a key to continue..."),usartout
            gosub charout
        next i
        gosub NLCR
    return
'
'
' Waits for a character from hardware serial line
AttendiTasto:
        gosub charin
        if usartin = 0 then AttendiTasto
    return
'
'
' Sends a character to USART transmitter
' (blocking)
CharOut: 
        Peek pir1,UsartST        ' Get Flag in UsartST = B0
        If Bit4 = 0 Then charout ' Wait for transmission register empty
        Poke TXREG,Usartout      ' Put data in transmission register
    Return                       ' Return to caller
'
'
' Get a character from USART receiver
' (non blocking)
CharIn: UsartIn = 0             ' Preset to no char received
        Peek PIR1,Usartst       ' Get Flag in UsartST = B0
        If Bit5 = 0 Then ciret  ' If reception flag is 0, exit
        Peek RCREG,UsartIn      ' Put received characther in UsartIn = B1
ciret:  
    Return