TABLE OF CONTENTS

/IO_Serial [ Modules ]

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DESCRIPTION

Serial communication IO subsystem. Session-based, only one session at time.

IO_Serial/Baud_calculation [ Constants ]

[ Top ] [ IO_Serial ] [ Constants ]

DESCRIPTION

Calculates the baud rate register value and the resulting real baud rate and the error.

DECLARATION

Const Os_serial_ubrr_val =((_xtal + Os_serial_baud * 8) /(os_serial_baud * 16) - 1)
Const Os_serial_baud_real =(_xtal /(16 *(os_serial_ubrr_val + 1)))
Const Os_serial_baud_error =((os_serial_baud_real * 1000) / Os_serial_baud - 1000)

IO_Serial/Settings [ Constants ]

[ Top ] [ IO_Serial ] [ Constants ]

DESCRIPTION

Set the baudrate.

DECLARATION

#if Varexist( "Os_serial_baud") = False
   Const Os_serial_baud = 9600
#endif

IO_Serial/Os_serial_session_open [ Variables ]

[ Top ] [ IO_Serial ] [ Variables ]

DESCRIPTION

Bit is set while a Task uses the serial IO subsystem, other tasks trying to open it are put on a waiting list and suspended until its Free.

DECLARATION

Dim Os_serial_session_open As Bit

IO_Serial/Os_serial_close [ Functions ]

[ Top ] [ IO_Serial ] [ Functions ]

DESCRIPTION

Closes the session to let other tasks use the serial IO.

DECLARATION

Sub Os_serial_close()
   Disable Urxc
   Os_semaphore_release Os_serial_session_semaphore
End Sub

SEE ALSO

    IO_Serial/Os_serial_open

IO_Serial/Os_serial_init [ Functions ]

[ Top ] [ IO_Serial ] [ Functions ]

DESCRIPTION

Initializes the serial IO subsystem

DECLARATION

Sub Os_serial_init()

SOURCE

   Os_serial_session_semaphore = Os_semaphore_create(1)
   Os_serial_session_open = True
End Sub

IO_Serial/Os_serial_ioctl [ Functions ]

[ Top ] [ IO_Serial ] [ Functions ]

DESCRIPTION

T

DECLARATION

Sub Os_serial_ioctl()

End Sub

SEE ALSO

    a

IO_Serial/Os_serial_open [ Functions ]

[ Top ] [ IO_Serial ] [ Functions ]

DESCRIPTION

Prior to send/receive, a Task has to open the session. When another Task is using the serial IO, either an error is returned to the calling Task or it gets blocked until the serial IO is Free again.

DECLARATION

Function Os_serial_open(byval Queuemode As Word , Byref Receivebuffer As Word , Byval Buffersize As Word) As Byte
   Os_serial_session_open = Os_semaphore_aquire Os_serial_session_semaphore , Queuemode
   Os_serial_open = Os_serial_session_open
   Os_serial_tx_complete = Os_serial_session_open

   If Receivebuffer <> 0 Then
      Os_serial_rxbuffer_start = Receivebuffer
      Os_serial_rxbuffer_w_ptr = Receivebuffer
      Os_serial_rxbuffer_r_ptr = Receivebuffer
      Os_serial_rxbuffer_end = Receivebuffer + Buffersize
   End If
   Ubrr = Os_serial_ubrr_val
   Enable Urxc
End Function

SEE ALSO

    IO_Serial/Os_serial_close

IO_Serial/Os_serial_read [ Functions ]

[ Top ] [ IO_Serial ] [ Functions ]

DESCRIPTION

Reads a given count of bytes to a memory location, initiates the Interrupt-driven receive loop

DECLARATION

Function Os_serial_read(byref Datapointer As Word , Byref Datalength As Word) As Word
   Local Bytesread As Word
   Local Databyte As Byte
   Bytesread = 0
   If Os_serial_session_open = True Then
      For Bytesread = 1 To Datalength
         If Os_serial_rxbuffer_w_ptr <> Os_serial_rxbuffer_r_ptr Then
            Databyte = Inp(os_serial_rxbuffer_r_ptr)
            If Os_serial_rxbuffer_r_ptr = Os_serial_rxbuffer_end Then
               Os_serial_rxbuffer_r_ptr = Os_serial_rxbuffer_start
            Else
               Incr Os_serial_rxbuffer_r_ptr
            End If
         Else
            Exit For
         End If
         Out Datapointer , Databyte
         Incr Datapointer
      Next
   End If
   Return Bytesread
End Sub

SEE ALSO

    IO_Serial/Os_serial_read_byte

IO_Serial/Os_serial_read_byte [ Functions ]

[ Top ] [ IO_Serial ] [ Functions ]

DESCRIPTION

Reads one byte from the serial IO, returns 0 if nothing to receive.

DECLARATION

Function Os_serial_read_byte() As Byte
   Local Databyte As Byte
   If Os_serial_session_open = True And Os_serial_rxbuffer_w_ptr <> Os_serial_rxbuffer_r_ptr Then
      Databyte = Inp(os_serial_rxbuffer_r_ptr)
      If Os_serial_rxbuffer_r_ptr = Os_serial_rxbuffer_end Then
         Os_serial_rxbuffer_r_ptr = Os_serial_rxbuffer_start
      Else
         Incr Os_serial_rxbuffer_r_ptr
      End If
   Else
      Databyte = 0
   End If
   Return Databyte
End Function

SEE ALSO

    IO_Serial/Os_serial_read

IO_Serial/Os_serial_udre_isr [ Functions ]

[ Top ] [ IO_Serial ] [ Functions ]

DESCRIPTION

Interrupt routine transmitting the contents of a buffer

DECLARATION

Os_serial_udre_isr:
   Udr = Inp(os_serial_txbuffer_ptr)                        ' send byte   '
   Incr Os_serial_txbuffer_ptr                              ' update buffer pointer   '
   Decr Os_serial_txbuffer_index
   If Os_serial_txbuffer_index = 0 Then
      Disable Udre                                          ' buffer empty: disable UDRE   '
      Os_serial_tx_complete = True
   End If
Return

SEE ALSO

    IO_Serial/Os_serial_urxc_isr

IO_Serial/Os_serial_urxc_isr [ Functions ]

[ Top ] [ IO_Serial ] [ Functions ]

DESCRIPTION

Interrupt routine receiving data to a ring buffer

DECLARATION

Os_serial_urxc_isr
   ___r16 = Inp(udr)
   Out Os_serial_rxbuffer_w_ptr , ___r16
   Incr Os_serial_rxbuffer_w_ptr
   If Os_serial_rxbuffer_w_ptr = Os_serial_rxbuffer_end Then
      Os_serial_rxbuffer_w_ptr = Os_serial_rxbuffer_start
   End If
Return

SEE ALSO

    IO_Serial/Os_serial_udre_isr

IO_Serial/Os_serial_write [ Functions ]

[ Top ] [ IO_Serial ] [ Functions ]

DESCRIPTION

Sends a desired count of bytes from the given memory location, initiates the Interrupt-driven transmit loop

DECLARATION

Sub Os_serial_write(byref Datapointer As Word , Byval Datalength As Word)
   If Os_serial_session_open = True Then
      While Os_serial_tx_complete = False : Wend            ' wait for previous message to transmit if neccessary   '
      Os_serial_tx_complete = False
      Os_serial_txbuffer_ptr = Datapointer                  ' set internal buffer pointer   '
      Os_serial_txbuffer_index = Datalength

      Os_serial_tx_ready_loop:                              ' wait until tx buffer is ready   '
         sbis UCSRA, UDRE
         rjmp Os_serial_tx_ready_loop

      Udr = Inp(os_serial_txbuffer_ptr)                     ' send first byte   '
      Incr Os_serial_txbuffer_ptr                           ' update buffer pointer   '
      Decr Os_serial_txbuffer_index
      If 0 < Os_serial_txbuffer_index Then
         Enable Udre                                        ' tx buffer not empty: enable Interrupt driven transmission   '
      Else
         Os_serial_tx_complete = True
      End If
   End If
End Sub