' **********************************************************************
' ** Program: gmbi2ce.BAS    -    Version : 1.1   -   14 June 2005    **
' ** Compiler : Bascom AVR IDE - LIB 1.11.7.4                         **
' ** Board : GMB HR168 and GMM AM32                                   **
' ** 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                      **
' ** Written by:  Graziano Gaiba                                      **
' **********************************************************************
'
' 14.06.05 - Rel 1.1 By Graziano Gaiba
' These demos allow to communicate to I2C BUS devices connected to CN8.
' It is possible to read or write bytes at any slave address and location
' address input by console. In detail, when reading the byte read is visualized
' and when writing the byte input is sent.
'
'
' !!!!!!!!!!!!!!!!!!!!!!!!!!! IMPORTANT !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
' In menu Options | Compiler | Chip, set:
'
' Chip:       M32
' HW Stack:   at least 64
' Soft Stack: at least 32
' Framesize:  at least 64
'
'
$regfile = "m32def.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

' Time out in case a TWI command receives no response
Const Ee_timeout = 50000
'
'
'****************** Variables declaration **********************
'
Dim A As Eram Byte At 1023
'
'****************** Procedures declartion **********************
'
Declare Sub Clrscr()                                        ' Clears the screen
Declare Sub Errore()                                        ' Error message
Declare Function Leggi_char() As Byte                       ' Reads one character (blocking)
Declare Sub Demo_twi()
' Send a command to TWI device, waits for a response and returns TWI status
Declare Function Twi_cmd(byval Cmd As Byte) As Byte
Declare Sub Check_ready()
'
'************************** Main program ******************************
'
Main:
  Print Chr(clrscr);                                        ' Clears the screen
  Print "Demo 1.1 for GMM AM32 + GMB HR168"
  Print
  Call Check_ready()
  Do
      Call Demo_twi()
  Loop

  Do
  Loop
End
'
'************************ Program end ***************************
'
'
' **************************** Procedures ******************************
'
'
' ************************* Sends 25 Line Feed ***************************
' Generic console clear screen function.
' Parameters:
' Input : nothing
' Output : nothing
' ************************************************************************
'
Sub Clrscr
   Local I As Byte

   For I = 1 To 25
      Print
   Next I
End Sub
'
'
' Prints "Error: "
'
Sub Errore()
   Print "Error: ";
End Sub
'
'
' Reads a character in blocking way,converts it in capital letter and prints it
'
Function Leggi_char() As Byte

   Local C As Byte

   C = Waitkey()
   Print Chr(c)
   C = C And &HDF                                           ' Converts ASCII character in capital letter

   Leggi_char = C
End Function
'
'
' Writes command passed in parameter cmd into control register TWI and waits
' for the completion of operation, then reads the status of TWI interface and
' returns it.
'
Function Twi_cmd(byval Cmd As Byte) As Byte

  Local Time_out As Word , I As Byte

  Twcr = Cmd                                                ' Writes the command
  Time_out = 0                                              ' Timeout counter
  Do
     Incr Time_out                                          ' Increment counter
  Loop Until Twcr.twint = 1 Or Time_out = Ee_timeout
  ' Reads status and masks not significant bits
  I = Twsr
  I = I And &HF8
  Twi_cmd = I
End Function
'
'
' Demo of hardware two wires serial interface (TWI) usage.
'
Sub Demo_twi()

   Local S_addr As Word , Time_out As Word
   Local Dato As Byte , Char As Byte

   Ddrc = Ddrc And &HCF
   Portc = Portc Or &H30                                    ' Enables pull-up
   Twsr = Twsr And &HFC                                     ' No prescaler
   Twbr = 72                                                ' Clock rate 46080 Hz
   Time_out = 0                                             ' Time-out for stop
   Print "Demo TWI"
   Print
   Print "Actions:"
   Print
   Do
      Print "A) Write"
      Print "B) Read"
      Print "C) Exit"
      Print
      Print "Select: ";
      Char = Leggi_char()
      If Char <> "C" Then
         Print
         Inputhex "Slave and data address in hex (e.g. A804): " , S_addr
         Select Case Char
            Case "A" : Inputhex "Data in hex (e.g. 01): " , Dato
                        Print
                        If Twi_cmd(&Ha4) = &H08 Then        ' Start
                           Twdr = High(s_addr)              ' Send SLA+W
                           If Twi_cmd(&H84) = &H18 Then
                              Twdr = Low(s_addr)            ' Send address
                              If Twi_cmd(&H84) = &H28 Then
                                 Twdr = Dato                ' Send data
                                 If Twi_cmd(&H84) = &H28 Then
                                    Twcr = &H94             ' Stop
                                                ' Wait for stop
                                    Do                      ' completed or
                                      Incr Time_out         ' Time Out
                                    Loop Until Twcr.twsto = 0 Or Time_out = Ee_timeout
                                 Else
                                    Call Errore()
                                    Print "data"
                                 End If
                              Else
                                 Call Errore()
                                 Print "address"
                              End If
                           Else
                              Call Errore()
                              Print "SLA+W"
                           End If
                        Else
                           Call Errore()
                           Print "start"
                        End If

            Case "B" : If Twi_cmd(&Ha4) = &H08 Then         ' Start
                          Twdr = High(s_addr)               ' Send SLA+W
                           If Twi_cmd(&H84) = &H18 Then
                              Twdr = Low(s_addr)            ' Send address
                              If Twi_cmd(&H84) = &H28 Then
                                 If Twi_cmd(&Ha4) = &H10 Then       ' Repeat start
                                    Twdr = High(s_addr) Or 1       ' Send SLA+R
                                    If Twi_cmd(&H84) = &H40 Then
                  ' Use Twi_cmd(&HC4) to perform two or more consecutive read.
                  ' Intercept code &H50 if read performed is the last one of
                  ' the sequence, otherwise use the code below.
                                       If Twi_cmd(&H84) = &H58 Then       ' Read data
                                          Dato = Twdr
                                          Twcr = &H94       ' Stop
                                                      ' Wait for stop
                                          Do                ' completed or
                                            Incr Time_out   ' Time Out
                                          Loop Until Twcr.twsto = 0 Or Time_out = Ee_timeout
                                          Print "Read: " ; Hex(dato)
                                          Print
                                       Else
                                          Call Errore()
                                          Print "data"
                                       End If
                                    Else
                                       Call Errore()
                                       Print "SLA+R"
                                    End If
                                 Else
                                    Call Errore()
                                    Print "start"
                                 End If
                              Else
                                 Call Errore()
                                 Print "address"
                              End If
                           Else
                              Call Errore()
                              Print "SLA+W"
                           End If
                        Else
                           Call Errore()
                           Print "start"
                        End If
         End Select
         Twcr.twen = 0                                      ' Disables TWI peripheral
      End If
   Loop Until Char = "C"
End Sub
'
'
' Check for hardware ready
'
Sub Check_ready()
Test:
   If A = &H55 Then
      Goto L2
   Else
      Goto Test
   End If
L2:
End Sub