' ****************************************************************
' * File:  uk_gmb_ser.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 is a simple example of communication capableto work
' with all electric protocols available on CN2 (RS 232, RS 422,
' RS 485, current loop or TTL).
' In detail, through high level functions, it is possible to
' program baud rate from console, then each character received
' from serial port is sent to the port itself; reception of
' character 'r' decides how to manage the communication direction
' (signal DIR) for RS 422 and RS 485.
'
' Rel 1.1 - by Graziano Gaiba
' Demo program for low level EUSART usage with GMB HR168 driven
' by Mini Module GMM 4620
'
'
' ******************** Compiler definitions **********************
'
program uk_gmb_ser
'
' ******************* Constants declaration **********************
'
const ASC_r = 114
const ASC_rU = 82
'
' ******************** Variables declaration *********************
'
' Generic variables
dim d_in as byte
'
'
' **************** 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
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
'
'
' Transmission of a signle character using low level EUSART manipulation.
' Char to transmit must be in variable .
' It blocks until transmitters is free.
sub procedure tx_char(dim char_to_tx as byte)
    ' Wait for transmitter available
    do
        nop
    loop until txsta.1 = 1
    txreg = char_to_tx
end sub
'
'
' Check if a character has been received.
' If a character reception has been completed, returns 1,
' otherwise 0.
sub function rx_status as byte

    dim kbhit as byte
    
    if pir1.5 = 1 then
        pir1.5 = 0
        kbhit = 1
    else
        kbhit = 0
    end if
    
    Result = kbhit
end sub
'
'
' Reception of a signle character using low level EUSART manipulation.
' Does NOT check if a character reception has been completed.
sub function rx_char as byte
    Result = rcreg
end sub
'
'************************** Main Program *******************************
'
main:
    Init_cpu
    ' Turn OFF relays
    set_relays(0)
    ' We need low level communication because DIR signal is not managed by
    ' PIC BASIC PRO high level instructions
    ' Disable auto baud-rate detection, 8 bit baud-rate generator
    baudctl = 0
    ' Value for baud rate 19200 and above settings
    '              Fosc
    ' SPBRG = --------------  -  1
    '          16 * BaudRate
    spbrg = 31
    ' High baud rate, Asynchronous mode, Enable transmitter, 8 bit transmission
    txsta = $24
    ' Enable receiver, 8 bit reception, Enable serial port
    rcsta = $90

    clrscr
    print_USART("Low level EUSART demo Rel 1.1 for GMM 4620 rel 120304 and GMB HR168 rel 110104")
    print_CRLF
    print_CRLF
    print_USART("This demo shows how to configure the boards to use RS 232, TTL, RS 422, RS 485")
    print_CRLF
    print_USART("serial communication.")
    print_CRLF
    print_USART("Following the instructions allows to test RS 232 communication at low level,")
    print_CRLF
    print_USART("that means controlled by assembly instructions rather than BASIC commands.")
    print_CRLF
    print_USART("Next, RS 422 or RS 485 is configured and used. Also a direction signal")
    print_CRLF
    print_USART("is used in case of RS 485.")
    print_CRLF
    wait_key
    print_CRLF
    print_CRLF
    print_USART("In RS 232: on GMM 4620 set ON switches from 1 to 3, set OFF all others,")
    print_CRLF
    print_USART("EUSART management is made by PIC BASIC PRO, see documentation for more info.")
    print_CRLF
    print_USART("Set OFF switches 2 and 3, set ON switches 4 and 5, to have UART TTL signals")
    print_CRLF
    print_USART("directly to the socket pins.")
    print_CRLF
    print_USART("Connect J10 in 1-2.")
    print_CRLF
    wait_key
    print_CRLF
    print_CRLF
    print_USART("Test in RS232, then configure GMB for other protocol:")
    print_CRLF
    print_USART("turn off power supply, set DSW1:")
    print_CRLF
    print_USART("2=3=OFF,4=5=ON, then:")
    print_CRLF
    print_CRLF
    print_CRLF
    print_USART("RS422:")
    print_CRLF
    print_USART("-install SN75176 or MAX483 on IC10 and IC11")
    print_CRLF
    print_USART("J5=2-3 J6,J7,J8=1-2 J10=1-2")
    print_CRLF
    print_CRLF
    print_CRLF
    print_USART("RS485:")
    print_CRLF
    print_USART("-install SN75176 or MAX483 on IC10")
    print_CRLF
    print_USART("-J5=1-2 J6,J7,J8=1-2 J10=1-2")
    print_CRLF
    print_CRLF
    print_CRLF
    print_USART("If at net termination->J3 and J4 connected")
    print_CRLF
    print_USART("R switches transmitter")
    print_CRLF
    ' DIR signal for RS 485 is PORTE.2
    trise.2 = 0
    porte.2 = 0
for_ever:
    if rx_status = 1 then
        d_in = rx_char
        if (d_in = ASC_r) or (d_in = ASC_rU) then
            if porte.2 = 0 then
                porte.2 = 1
            else
                porte.2 = 0
            end if
        end if
        tx_char(d_in)
    end if

    goto for_ever
end.