' **********************************************************************
' ** Program: gmbsere.BAS    -    Version : 1.1   -   29 January 2004 **
' ** Compiler : Bascom AVR IDE - LIB 1.11.7.4                         **
' ** Scheda : GMB HR84 and GMM AM08                                   **
' ** Society: grifo(r) ITALIAN TECHNOLOGY                             **
' ** Via Dell' Artigiano 8/6          40016 San Giorgio di Piano (BO) **
' ** Tel.+39 051 892 052     Fax +39 051 893 661                      **
' ** http://www.grifo.com    http://www.grifo.it                      **
' ** sales@grifo.it          tech@grifo.it          grifo@grifo.it    **
' **                                                                  **
' ** Written by:  Graziano Gaiba                                      **
' **********************************************************************
'
' Rel. 1.1   29.01.04 - By Graziano Gaiba
'
' This demo is a simple example of communication capable to 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.
'
'   Compiled file is smaller than 2048 bytes, so it can becompliled with free
'   demo of BASCOM AVR.
'
'
' !!!!!!!!!!!!!!!!!!!!!!!!!!! IMPORTANT !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
' In menu Options | Compiler | Chip, set:
'
' Chip:       M8
' HW Stack:   at least 64
' Soft Stack: at least 32
' Framesize:  at least 64
'
'
$regfile = "m8def.dat"
$crystal = 7372800
$baud = 19200
'
' ********************* Constans declarations *************************
'
Const Cret = 13                                             ' Codice di ritorno di carrello
Const Nl = 10                                               ' Codice nuova linea
Const Clrscr = 12                                           ' codice di clear screen
Const Bell = 7                                              ' codice di Bell

Const Enabled = 1                                           ' Value to activate driver 422 or 485
Const Disabled = 0                                          ' Value to deactivate driver 422 or 485

'
'****************** Variables declaration **********************
'
' Generic use
Dim Dir_ser As Bit                                          ' Transmission driver status

' Used by low level procedures
Dim Char As Byte
Dim Rate As Long                                            ' Baud rate required by the user

Ri Alias Ucsra.rxc                                          ' Reception completed
Ti Alias Ucsra.txc                                          ' Transmission completed
'
'********************* Procedures declaration *************************
'
Declare Sub Init()                                          ' Initialization
Declare Sub Txa(byval C As Byte)                            ' Manages transmission on serial line A
Declare Function Rxa() As Byte                              ' Manages reception on serial line A
'
'************************** Main program ******************************
'
Main:
   ' UART management in RS 232 and TTL
   Print
   Print "In RS 232: set ON switches 1 and 2, set OFF switches 3 and 4 of DSW1"
   Print "Software management is made by Bascom,see documentation for more info"
   Print "Set OFF switches 1 and 2, set ON switches 3 and 4, to have UART TTL signals"
   Print "directly to the socket pins."
   Print
   Print "Press a key to continue..."
   Char = Waitkey()
   Print
   Print "Connect J7 in 2-3"                                ' connection of DIR
   ' Low level communication because BASCOM
   ' does not manage direction with high level instructions
   Input "Baud rate:" , Rate
   ' UBRR = (7372800 / (16 * BaudRate)) - 1
   Rotate Rate , Left , 4
   Rate = 7372800 / Rate
   ' Before reprogramming serial port, transmission buffer must be emptied
   Waitms 10
   ' Bit x chr = 8"
   ' Stop bit  = 1"
   ' Parity    = No"
   ' Handshake = No"
   ' Baud rate = 19200"
   Ucsrc = &H86                                             ' Initialize Serial port 8 Bit , 1 Stop , No Interrupt
   Ubrrhi = &H00                                            ' Set Baud Rate 19200
   Ubrr = Rate

   Print "Test in RS232, then configure GMB for other protocol:"
   Print "turn off power supply, set DSW1:"
   Print "2=3=OFF,4=5=ON, then:"
   Print
   Print "RS422:"
   Print "-install SN75176 or MAX483 on IC1 and IC2"
   Print "-J2=1-2 J3=1-2 J4=1-2 J5=2-3"
   Print
   Print "RS485:"
   Print "-install SN75176 or MAX483 on IC1"
   Print "-J2=1-2 J3=1-2 J4=1-2 J5=1-2"
   Print
   Print "If at net termination->J1 connected"
   Print "R switches transmitter"

   Dir_ser = Disabled                                       ' memorize status
   Portb.1 = 0

   Do
      Char = Rxa()                                          ' riceive from serial A
      If Char <> 0 Then                                     ' is it a character?
         Call Txa(char)                                     ' Send it to serial A
         Char = Char Or &H20                                ' Turn in lowercase
         If Char = "r" Then
            If Dir_ser = Enabled Then                       ' if disabled
               Portb.1 = 1                                  ' enable transmission
                                                                 ' of driver 422 or 485
               Dir_ser = Disabled
            Else                                            ' viceversa
               Portb.1 = 0                                  ' disable transmission
                                                                 ' of driver 422 or 485
               Dir_ser = Enabled
            End If
         End If
      End If
   Loop
End
'
'************************ Program end ***************************
'
'
'**************************** Procedures ********************************
'
'
' Initializes demo
'
Sub Init()
   Ddrb.1 = 1                                               ' Dir signal
End Sub
'
'
' **************** Manages transmission on serial line A ***********************
' * This procedure allows to send on character to serial line A, character to  *
' * send in variable c.                                                        *
' ******************************************************************************
'
Sub Txa(byval C As Byte)                                    ' Manages transmission on serial line A
   Bitwait Ti , Set                                         ' Wait for previous character sent
   Ti = 0                                                   ' reset transmision bit
   Udr = Char                                               ' Send character
End Sub
'
'
' ***************** Manages reception from serial line A ***********************
' * This procedure returns the character received from serial line A,and       *
' * returns it, if no char received returns 0.        *                        *
' ******************************************************************************
'
'
Function Rxa() As Byte                                      ' Manages reception on serial line A
   If Ri = 1 Then
      Rxa = Udr                                             ' Read received character
   Else
      Rxa = 0                                               ' No character received
   End If
End Function