' ****************************************************************
' * File:  uk_gmb_da.pbas  -  Ver. 1.1                           *
' * Compiler: mikroBasic for PIC by mikroElektronica             *
' * IDE: mikroBasic for PIC by mikroElektronica                  *
' * Compiler Version: 1.1.5.0                                    *
' * Boards: GMM 4620 + GMB HR168                                 *
' *   GRIFO(R)   via Dell'Artigiano 8/6                          *
' *   40016 S. Giorgio di Piano (BO)                             *
' *   Tel. +39 051 892052                   Fax. +39 051 893661  *
' *   http://www.grifo.com                  http://www.grifo.it  *
' * by Graziano Gaiba                              22.02.05      *
' ****************************************************************
'
' This demo uses section CCP1 Mini Module to generate, on CN7,
' a PWM signal with preset frequency and duty cycle programmable
' in percent by console.
' Such signal, connected to an opportune intergrating circuit
' (RC network, operational amplifire with capacitor on feedback, etc.)
' allows to obtain an anlog signal like the one of a D/A.
' Demo execution depends on serial line configuration.
'
' Rel 1.1 - by Graziano Gaiba
' Demo program for low level PWM usage with GMB HR168 driven
' by Mini Module GMM 4620
'
'
' ******************** Compiler definitions **********************
'
program uk_gmb_da
'
' ******************* Constants declaration **********************
'
const RTCSLA = $A0
'
' ******************** Variables declaration *********************
'
' Generic variables
dim i as byte
'
' Used by PWM demo management
dim duty_cycle as word
'
'
' **************** Procedures definition ******************
'
'
' CPU and signals directions initialization
sub procedure Init_cpu
    ADCON1=$0f        ' Imposta come I/O digitale i pin AN0..12
    CMCON=$07         ' Imposta come I/O digitale RA0..4
' Optocoupled Inputs of CN1 are:
' IN1-1 <-> RA0
' IN2-1 <-> RA1
' IN3-1 <-> RB0
' IN4-1 <-> RB1
' IN5-1 <-> RA4
' IN6-1 <-> RC0
' IN7-1 <-> RC1
' IN8-1 <-> RC5
    trisa.0=1
    trisa.1=1
    trisa.4=1
    trisb.0=1
    trisb.1=1
    trisc.0=1
    trisc.1=1
    trisc.5=1
' Optocoupled Inputs of CN2 are:
' IN1-2 <-> RD0
' IN2-2 <-> RD1
' IN3-2 <-> RD2
' IN4-2 <-> RD3
' IN5-2 <-> RD4
' IN6-2 <-> RD5
' IN7-2 <-> RD6
' IN8-2 <-> RD7
    trisd=$ff
' Relay outputs of CN3 are:
' OUT A1 <-> RB4
' OUT A2 <-> RB5
' OUT B1 <-> RB6
' OUT B2 <-> RB7
' OUT C1 <-> RB3
' OUT C2 <-> RB2
    trisb=trisb and $03
' Relay outputs of CN4 are:
' OUT D1 <-> RA3
' OUT D2 <-> RC2 (J10 in position 3-4)
    trisa.3=0
    trisc.2=0
    ' Initialize module USART (8 bit, 19200 baud rate,
    ' no parity)
    Usart_init(19200)
end sub
'
'
' Send a string of characters to the serial port
sub procedure print_USART(dim byref txt as char[255])
    dim i as byte
    dim l as byte

    l = txt[0]
    for i = 1 to l
        USART_Write(txt[i])
    next i
end sub
'
'
' Send CR + LF
sub procedure print_CRLF
    USART_Write(10)
    USART_Write(13)
end sub
'
'
' Clear screen, sending 25 times CR + LF.
sub procedure clrscr

    dim i as byte
    
    for i = 0 to 24
    print_CRLF
    next i
end sub
'
'
' Asks for a key press
sub procedure wait_key
    dim c as byte

    print_usart("Press a key...")
    do
        nop
    loop until USART_Data_Ready = 1
    c = USART_Read
end sub
'
'
' Procedure to set the status of the relays on connectors CN3 and CN4.
' According to the bits of port_val, each relay is turned ON
' (contact closed) or OFF (contact open).
' Bits of port_val have this meanging:
' -- CN3
' port_val.0 drives relay OUT A1
' port_val.1 drives relay OUT A2
' port_val.2 drives relay OUT B1
' port_val.3 drives relay OUT B2
' port_val.4 drives relay OUT C1
' port_val.5 drives relay OUT C2
' -- CN4
' port_val.6 drives relay OUT D1
' port_val.7 drives relay OUT D2
'
' Each bit has the following meaning:
'   bit              Meaning
'    0    Relay turned OFF (contact open)
'    1    Relay turned ON (contact closed)
sub procedure set_relays(dim port_val as byte)
' Relays are driven in complemented logic, so port_val must be
' complemented too
    port_val=port_val xor $ff
    portb.4=port_val.0
    portb.5=port_val.1
    portb.6=port_val.2
    portb.7=port_val.3
    portb.3=port_val.4
    portb.2=port_val.5

    porta.3=port_val.6

    portc.2=port_val.7
end sub
'
'
' Check if the input parameter is an hexadecimal digit.
sub function is_HEX_digit(dim v as byte) as byte
    dim flag as byte

    flag = 0
    if (v >=48) and (v <= 57) then
        flag = 1
    end if
    if (v >= 65) and (v <= 70) then
        flag = 1
    end if
    if (v >= 97) and (v <= 102) then
        flag = 1
    end if

    Result = flag
end sub
'
'
' Returns the value of a single hexadecimal digit.
' Does NOT check if input parameter is an hexadecimal digit.
sub function HEX_val(dim v as byte) as byte
    v = v - 48
    if v > 9 then
        v = v - 17
        if v > 5 then
            v = v - 32
        end if
        v = v + 10
    end if

    Result = v
end sub
'
'
' Inputs an hexadecimal vale of up to four digits.
' Input parameter is number of digits, it returns an interger
' containing the value input by te user.
' It can manage backspace (ASCII 08) and accepts digits from
' '0' to '9', from 'a' to 'f' and from 'A' to 'F'.
' It sends a bell character (ASCII 07) when receives a character
' not acceptable for input, or user tries to input or delete out
' of possible range.
sub function inputHEX(dim n_char as byte) as word
    dim str_input as byte[6]
    dim idx as byte
    dim chr_input as byte
    dim pow_of_16 as word[5]
    dim value as word

    pow_of_16[1] = 1
    pow_of_16[2] = 16
    pow_of_16[3] = 256
    pow_of_16[4] = 4096
    ' Index must start from 1
    idx = 1
    Inc(n_char)
    ' No character in input
    chr_input = 0
    ' Starting value
    value = 0
    ' Loop until CR is received
    while chr_input <> 13
        ' If a data is ready
        if usart_data_ready = 1 then
            ' Read it
            chr_input = USART_Read
            ' If backspace (ASCII BS)
            if chr_input = 8 then
                ' and buffer is not empty
                if idx > 1 then
                    ' Send data read
                    USART_Write(chr_input)
                    ' Delete character
                    USART_Write(32)
                    USART_Write(chr_input)
                    ' delete last input data
                    Dec(idx)
                else
                    ' Bell to indicate an error
                    USART_Write(7)
                end if
            end if
            ' If CR received, elaborate the value and return it
            if chr_input = 13 then
                n_char = 0
                while idx > 1
                    Dec(idx)
                    Inc(n_char)
                    value = value + HEX_val(str_input[n_char]) * pow_of_16[idx]
                wend
            else
                ' If character can be input
                if idx < n_char then
                    ' If data received is in valid range:
                    ' 0..9 or 'a'..'f' or 'A'..'F'
                    if is_HEX_digit(chr_input) = 1 then
                        ' Send data read
                        USART_Write(chr_input)
                        ' Store it in input buffer
                        str_input[idx] = chr_input
                        ' Point to next position
                        Inc(idx)
                    end if
                else
                    ' Bell to indicate an error
                    USART_Write(7)
                end if
            end if
        end if
    wend
    print_CRLF
    Result = value
end sub
'
'************************** Main Program *******************************
'
main:
    Init_cpu
    ' Turn OFF relays
    set_relays(0)
    ' Clear screen
    clrscr
    print_USART("Low level PWM demo Rel 1.1 for GMM 4620 rel 120304 and GMB HR168 rel 110104")
    print_CRLF
    print_CRLF
    print_USART("This demo generates a PWM signal at about 10 kHz on pin 6 of CN7.")
    print_CRLF
    print_USART("To work properly, pin 6 of CN7 must be not connected to relay OUT D2 and")
    print_CRLF
    print_USART("to RS 485 section so please connect J10 in 1-2 and 4-5.")
    print_CRLF
    wait_key
    print_CRLF
    print_CRLF
    ' Prescaler of Timer 2 is 1
    t2con = 0
    ' Pin CCP1 is output
    trisc.2 = 0
    ' Module CCP1 in CCP standard PWM mode
    ccp1con = $0f
    ' About 10 KHz of frequency for PWM signal
    pr2 = $ff
    ' Start timer 2, timer 2 is time base for PWM mode of CCP
    t2con.2 = 1
for_ever:
    print_USART("Duty cycle (hexadecimal from 0 to 03FF): ")
    duty_cycle = inputHEX(4)
    if duty_cycle > $3ff then
        goto for_ever
    end if
    ccp1con.4 = duty_cycle.0
    ccp1con.5 = duty_cycle.1
    ccpr1l = lo(duty_cycle) >> 2
    i = hi(duty_cycle)
    ccpr1l.6 = i.0
    ccpr1l.7 = i.1

    goto for_ever
end.