' **********************************************************************
' ** Program: k51ppoe.BAS    -    Version : 1.1   -   20 June 2005    **
' ** Compiler : Bascom AVR IDE - LIB 1.11.7.4                         **
' ** Board : GMB HR168 and GMM AM128 + K51-AVR                        **
' ** 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                                      **
' **********************************************************************
'
' 20.06.05 - Rel 1.1 By Graziano Gaiba
' This demo allows to drive an I2C BUS peripheral on board of K51-AVR, PCF8574,
' through mini-BLOCK module GMB HR168 and grifo(r) mini module.
' PCF 8574 is an I/O expander that allows to drive 8 TTL digital lines, both as
' input and as output, all the operations of read and write are performed
' through synchronous serial interface I2C BUS.
' This demo activates in sequence one line at a time, creating the classic bit
' shift to the right and to the left, and writes 'out' on the 7 segments
' display of K51-AVR, near the characters 'out'.
'
'
'
' !!!!!!!!!!!!!!!!!!!!!!!!!!! IMPORTANT !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
' In menu Options | Compiler | Chip, set:
'
' Chip:       M128
' HW Stack:   at least 64
' Soft Stack: at least 32
' Framesize:  at least 64
'
'
$regfile = "m128def.dat"
$crystal = 7372800
$baud = 19200
'
'********************* Constants declaration ***************************
'
' Time out in case a TWI command receives no response
Const Ee_timeout = 50000
' TWI reading options
Const Twi_ack = 1
Const Twi_nack = 0

Const Saa1064 = &H38                                        ' Slave address SAA1064
Const Wsaa1064 = &H70                                       ' Slave address SAA1064 in Write
Const Rsaa1064 = &H71                                       ' Slave address SAA1064 in Read
'****************** Addresses list for Saa1064 *************************
Const Ctb = 0                                               ' Address Control byte
Const Dig1 = 1                                              ' Address Digit 1
Const Dig2 = 2                                              ' Address Digit 2
Const Dig3 = 3                                              ' Address Digit 3
Const Dig4 = 4                                              ' Address Digit 4
' **********************************************************************
' Comment the declaration of the component not used, uncomment the other
' declaration
'
'Const Pcf8574 = &H3C                 ' Slave address PCF8574A
'Const Wpcf8574 = &H78                ' Slave address PCF8574A in Write
'Const Rpcf8574 = &H79                ' Slave address PCF8574A in Read

Const Pcf8574 = &H24                                        ' Slave address PCF8574P
Const Wpcf8574 = &H48                                       ' Slave address PCF8574P in Write
Const Rpcf8574 = &H49                                       ' Slave address PCF8574P in Read
'
'*********************** Variables declaration *************************
'
' General purpose
Dim I2cstatus As Byte

Dim Pout As Byte                                            ' Value to set in output
Dim X As Byte                                               ' Generic use
Dim Dato As Byte                                            ' Counter
'
'********************* Procedures declaration **************************
'
'
' Send a command to TWI interface, wait for it to complete and returns status
Declare Function Twi_cmd(byval Cmd As Byte) As Byte
Declare Sub Twiinit(byval Clockrate As Byte)                ' Initialize TWI hardware interface
Declare Function Twistart() As Byte                         ' Generate a start by TWI hardware interface
Declare Function Twiwbyte(byval Dato As Byte) As Byte       ' Send a byte by TWI hardware interface
Declare Function Twirbyte(twi_data As Byte , Byval Assert_ack As Byte) As Byte       ' Read a byte from TWI hardware interface
Declare Function Twistop() As Byte                          ' Generate a stop by TWI hardware interface

Declare Sub Iniz()                                          ' Peripherals initialization
Declare Sub Check_ready()
Declare Function Check_ready_2() As Byte
'
'*************************** Main program ******************************
'
Main:                                                       ' Delay for signals settling
   Print Chr(12)
   Print "Demo output of 8 TTL signals of PCF8574."
   Print
   Call Check_ready()
   Print "One TTL signal shifts from left to right and viceversa."

   Call Iniz()                                              ' initializations
   Do
      Dato = 1                                              ' starting value
      For X = 1 To 7                                        ' cycle initialization
         Pout = Not Dato                                    ' complement the value
         I2cstatus = Twistart()                             ' Start sequence for I2CBUS
         I2cstatus = Twiwbyte(wpcf8574)
         I2cstatus = Twiwbyte(pout)
         I2cstatus = Twistop()
         'I2csend Wpcf8574 , Pout                            ' set the outputs
         Rotate Dato , Left                                 ' left shift of bits
         Waitms 255                                         ' delay
      Next X
      For X = 1 To 7                                        ' cycle initialization
         Pout = Not Dato                                    ' complement the value
         I2cstatus = Twistart()                             ' Start sequence for I2CBUS
         I2cstatus = Twiwbyte(wpcf8574)
         I2cstatus = Twiwbyte(pout)
         I2cstatus = Twistop()
         'I2csend Wpcf8574 , Pout                            ' set the outputs
         Rotate Dato , Right                                ' right shift of the bits
         Waitms 255                                         ' delay
      Next X
   Loop
End
'
'*************************** Programma end ******************************
'
'
'**************************** Procedures ********************************
'
' ********************** Peripherals initialization ********************
' This procedure performs all the system initializations.
' Parameters:
' Input : nothing
' Output : nothing
' ************************************************************************
'
Sub Iniz()                                                  ' Inizializzazione periferiche

   Local Valore As Byte

   ' Initialize hardware I2C BUS interface at about 72 kHz
   Call Twiinit(72)

   Do
      I2cstatus = Twistart()                                ' Start sequence for I2CBUS
      I2cstatus = Twiwbyte(rsaa1064)
      I2cstatus = Twirbyte(valore , Twi_nack)               ' Read the status register
      I2cstatus = Twistop()
      'I2creceive Rsaa1064 , Valore
   Loop Until Valore = 0                                    ' Wait for SAA1064 to turn on

   I2cstatus = Twistart()                                   ' Start sequence for I2CBUS
   I2cstatus = Twiwbyte(wsaa1064)                           ' Communicate the Slave address
   I2cstatus = Twiwbyte(ctb)                                ' Point to control register
   I2cstatus = Twiwbyte(&B00100111)                         ' bit0 =1 dynamic mode
                                          ' bit1 =1 digit 1+3 not blanked
                                          ' bit2 =1 digit 2+4 not blanked
                                          ' bit3 =0 no test segment
                                          ' bit4 =0 no 3mA segment current
                                          ' bit5 =1 6mA segment current
                                          ' bit6 =0 no 12mA segment current
                                          ' bit7 =0 indifferent
   I2cstatus = Twiwbyte(92)                                 ' set DY1 "o"
   I2cstatus = Twiwbyte(28)                                 ' set DY2 "u"
   I2cstatus = Twiwbyte(120)                                ' set DY3 "t"
   I2cstatus = Twiwbyte(0)                                  ' set DY4 off
   I2cstatus = Twistop()
End Sub
'
'******************************************************************************
'*                     I2C BUS hardware management procedures                 *
'******************************************************************************
'
'
'
' 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
'
'
' Initializes hardware TWI interface
'
Sub Twiinit(byval Clockrate As Byte)
   Twsr = Twsr And &HFC                                     ' No prescaler
   Twbr = Clockrate                                         ' Set clock rate
End Sub
'
'
' Send start for hardware TWI interface
'
Function Twistart() As Byte
   Twistart = Twi_cmd(&Ha4)                                 ' Start
End Function
'
'
' Send byte to hardware TWI interface
'
Function Twiwbyte(byval Dato As Byte) As Byte
   Twdr = Dato                                              ' Write data
   Twiwbyte = Twi_cmd(&H84)
End Function
'
'
' Read byte from hardware TWI interface
'
Function Twirbyte(twi_data As Byte , Byval Assert_ack As Byte) As Byte
   If Assert_ack = 1 Then
      Twirbyte = Twi_cmd(&Hc4)
   Else
      Twirbyte = Twi_cmd(&H84)
   End If

   Twi_data = Twdr
End Function
'
'
' Send stop on hardware TWI interface.
' Returns 0 if there are no errors, a value different from 0 in case of
' timeout.
'
Function Twistop() As Byte

   Local Time_out As Word

   Twcr = &H94                                              ' Stop
               ' Waits for the stop completer or timeout
   Time_out = 0
   Do
     Incr Time_out
   Loop Until Twcr.twsto = 0 Or Time_out = Ee_timeout

   If Time_out = Ee_timeout Then
      Twistop = 1
   Else
      Twistop = 0
   End If

End Function
'
'******************************************************************************
'*                              Generic procedures                            *
'******************************************************************************
'
'
'
' Supporting function for Check_ready().
'
Function Check_ready_2() As Byte

  Local Time_out As Word , I As Byte

  Time_out = 0                                              ' Timeout counter
  Do
     Incr Time_out                                          ' Increment counter
  Loop Until Twcr.twint = 1 Or Time_out = Ee_timeout
  I = Twsr
  I = I And &HF8
  Check_ready_2 = I
End Function
'
'
' Check for card ready
'
Sub Check_ready()

   Local Check As Byte , Test As Byte

   Do                                                       ' Loop to check for card ready
      Twsr = Twsr And &HFC
      Check = Twdr Or &HF4
      Test.4 = Not Check.3
      Twbr = 72
      Twcr = &HA4
      Check = Check_ready_2()
      Test = Check Or Twcr
      If Check = &H09 Then
         Test = &H67
      Else
         Test.1 = Not Test.1
      End If
      Twdr = &HA0
      Twcr = &H84
      Check = Check_ready_2()
      Twcr = &H94
      Waitms 27
   Loop Until Check = &H18 Or Test <> 1
   Twcr.twen = 0
End Sub