USART2 with ISRRX
Posted: Mon May 04, 2015 9:03 am
I want to use the ISRRX on second USART on a 46K22 and I rebuilt a ISSRX for the second USART renaming it UartBuffer2.bas
I still have not the MPU so I rely only on compilation and I noticed that in the USART2.BAS module there is a specific reference to 18F26K22 (which is exactly the same family of 18F46K22) and refers to TRISB instead of TRISG.
1) I can safely add the 18F46K22 to this verification?
2) Do you think that attachment source (ISRRX> UsartBuffer2) is correct?
It derives from a module of David John Barker wrote for Firewing ( with RunTo, LookFor very useful functions ) which I tried to apply what has already been written in ISRRX.BAS standard module.
I ask this with regard to overrun and RX2Priority setting for which are quite uncertain
I still have not the MPU so I rely only on compilation and I noticed that in the USART2.BAS module there is a specific reference to 18F26K22 (which is exactly the same family of 18F46K22) and refers to TRISB instead of TRISG.
1) I can safely add the 18F46K22 to this verification?
2) Do you think that attachment source (ISRRX> UsartBuffer2) is correct?
It derives from a module of David John Barker wrote for Firewing ( with RunTo, LookFor very useful functions ) which I tried to apply what has already been written in ISRRX.BAS standard module.
I ask this with regard to overrun and RX2Priority setting for which are quite uncertain
Code: Select all
Module UARTBuffer2
// import USART library...
Include "USART2.bas"
// set interrupt priority level...
#if IsOption(RX2_PRIORITY) And Not (RX2_PRIORITY in (ipLow, ipHigh))
#error RX2_PRIORITY, "Invalid option. Priority must be ipHigh or ipLow."
#endif
#option RX2_PRIORITY = ipHigh
Const PriorityLevel = RX2_PRIORITY
// size of the RX buffer...
#if IsOption(RX2_BUFFER_SIZE) And Not (RX2_BUFFER_SIZE in (1 to 1024))
#error RX2_BUFFER_SIZE, "Invalid option. Buffer size must be between 1 and 256 (bytes)."
#endif
#option RX2_BUFFER_SIZE = 64
Public Const BufferSize = RX2_BUFFER_SIZE
// local variables and aliases...
Dim
FBuffer(BufferSize) As Byte,
FIndexIn As Byte,
FIndexOut As Byte,
FByteRead As Byte,
FProcessByte As Boolean,
FMaybeOverrun As Boolean
// public variables and aliases...
Public Dim
USARTOverrun As USART2.Overrun,
BufferOverrun As Boolean,
DataByte As FByteRead,
DataChar As FByteRead.AsChar,
ProcessByte As FProcessByte
{
****************************************************************************
* Name : OnRX (PRIVATE) *
* Purpose : Interrupt Service Routine (ISR) to buffer incoming data *
****************************************************************************
}
Interrupt OnRX(PriorityLevel)
Dim FSRSave As Word
FSRSave = FSR0
BufferOverrun = FMaybeOverrun
If Not USART2.Overrun Then
FByteRead = USART2.RCRegister
If Not BufferOverrun Then
FProcessByte = true
// execute handler...
If FProcessByte Then
FBuffer(FIndexIn) = FByteRead
Inc(FIndexIn)
If FIndexIn > Bound(FBuffer) Then
FIndexIn = 0
EndIf
FMaybeOverrun = (FIndexIn = FIndexOut)
EndIf
EndIf
EndIf
FSR0 = FSRSave
End Interrupt
{
****************************************************************************
* Name : Initialize *
* Purpose : Initialize buffering - with optional OnData event handler *
****************************************************************************
}
Public Sub Initialize()
FIndexIn = 0
FIndexOut = 0
FMaybeOverrun = false
BufferOverrun = false
USART2.ClearOverrun
#if RX2_PRIORITY = ipLow
USART2.RCIPHigh = false
#endif
USART2.RCIEnable = true
Enable(OnRX)
End Sub
{
****************************************************************************
* Name : Reset *
* Purpose : Reset module *
****************************************************************************
}
Public Sub Reset()
Disable(OnRX)
Initialize()
End Sub
{
****************************************************************************
* Name : Start *
* Purpose : Start interrupt handling *
****************************************************************************
}
Public Sub Start()
Enable(OnRX)
End Sub
{
****************************************************************************
* Name : Stop *
* Purpose : Stop interrupt handling *
****************************************************************************
}
Public Sub Stop()
Disable(OnRX)
End Sub
{
****************************************************************************
* Name : DataAvailable *
* Purpose : Check to see if there is data in the buffer *
****************************************************************************
}
Public Function DataAvailable() As Boolean
' Disable(OnRX)
Result = FIndexIn <> FIndexOut
' Enable(OnRX)
End Function
{
****************************************************************************
* Name : Overrun *
* Purpose : Returns true if RC register or buffer has overrun, false *
* : otherwise *
****************************************************************************
}
Public Function Overrun() As Boolean
Result = USART2.Overrun Or BufferOverrun
End Function
{
****************************************************************************
* Name : GetByte (PRIVATE) *
* Purpose : Get a single byte from the buffer *
****************************************************************************
}
Function GetByte() As Byte
FMaybeOverrun = false
Result = FBuffer(FIndexOut)
Inc(FIndexOut)
If FIndexOut > Bound(FBuffer) Then
FIndexOut = 0
EndIf
End Function
{
****************************************************************************
* Name : ReadByte *
* Purpose : Read a single byte from the buffer *
****************************************************************************
}
Public Function ReadByte() As Byte
Disable(OnRX)
Result = GetByte
Enable(OnRX)
End Function
{
****************************************************************************
* Name : ReadWord *
* Purpose : Read a word from the buffer *
****************************************************************************
}
Public Function ReadWord() As Word
Disable(OnRX)
Result.Bytes(0) = GetByte
Result.Bytes(1) = GetByte
Enable(OnRX)
End Function
{
****************************************************************************
* Name : ReadLongWord *
* Purpose : Read a long word from the buffer *
****************************************************************************
}
Public Function ReadLongWord() As LongWord
Disable(OnRX)
Result.Bytes(0) = GetByte
Result.Bytes(1) = GetByte
Result.Bytes(2) = GetByte
Result.Bytes(3) = GetByte
Enable(OnRX)
End Function
{
****************************************************************************
* Name : ReadFloat *
* Purpose : Read a floating point number from the buffer *
****************************************************************************
}
Public Function ReadFloat() As Float
Disable(OnRX)
Result.Bytes(0) = GetByte
Result.Bytes(1) = GetByte
Result.Bytes(2) = GetByte
Result.Bytes(3) = GetByte
Enable(OnRX)
End Function
{
****************************************************************************
* Name : ReadStr *
* Purpose : Read a string from the buffer. Optional parameter pTerminator *
* : to specify the input string terminator character. The function *
* : returns the number of characters read *
****************************************************************************
}
Public Function ReadStr(ByRef pText As String, pTerminator As Char = null) As Byte
Dim Ch As Char
Dim Text As POSTINC0
Disable(OnRX)
FSR0 = AddressOf(pText)
Result = 0
Repeat
Ch = GetByte
If Ch <> pTerminator Then
Text = Ch
Inc(Result)
EndIf
Until Ch = pTerminator
Text = 0
Enable(OnRX)
End Function
'****************************************************************************
'* Name : LookFor *
'* Purpose : Look for a string - but will not eat input bytes *
'****************************************************************************
Public Function LookFor(str As String) As Boolean
Dim indexIn As Word
Dim indexOut As Word
Dim index As Byte
Dim data As Byte
indexIn = FIndexIn
indexOut = FIndexOut
index = 0
Result = False
While (indexIn <> indexOut) And Not Result
data = FBuffer(indexOut)
Inc(indexOut)
If indexOut > Bound(FBuffer) Then
indexOut = 0
End If
If str(index) = Char(data) Then
Inc(index)
Else
index = 0
End If
If str(index) = Char(0) Then
Result = True
Else
Result = False
End If
End While
End Function
'****************************************************************************
'* Name : RunTo *
'* Purpose : Look for a string - eats input bytes *
'****************************************************************************
Public Function RunTo(str As String) As Boolean
Dim index As Byte
Dim data As Byte
Index = 0
Result = False
While DataAvailable And Not Result
data = ReadByte()
If str(index) = Char(data) Then
Inc(index)
Else
index = 0
End If
If str(index) = Char(0) Then
Result = True
Else
Result = False
EndIf
End While
End Function
FIndexOut = 0
FIndexIn = 0
