On Time RTOS-32 Documentation

RTKernel-32 Programming Manual

RTKernel-32 Reference Manual

Module RTKernel-32

Module FineTime

Function COMSetBoardType

Function COMSetIOBase

Function COMSetIRQ

Function COMPortInit

Function COMHasFIFO

Function COMEnableFIFO

Function COMSetProtocol

Function COMAllocateBuffers

Function COMEnableInterrupt

Function COMDisableInterrupt

Function COMSendChar

Function COMSendCharTimed

Function COMSendBlock

Function COMSendBlockTimed

Function COMWaitSendBufferEmpty

Function COMSetModemStatusHook

Function COMReceiveCharPolled

Function COMSendCharPolled

Function COMLineStatus

Function COMModemStatus

Function COMModemControl

Function COMError

Module RTKeybrd

Module RTTextIO

Previous

Next

Function COMLineStatus

COMLineStatus enquires the line status register of a port:

BYTE COMLineStatus(int Port);

Parameters

Port

The port to enquire.

return value

The contents of the Line Status Register is returned. The return value is bit-oriented; the following bits can be set:

Value	Meaning
COM_DATA_READY	A data byte has been received.
COM_OVERRUN	An overrun error has occurred.
COM_PARITY	A parity error has been detected.
COM_FRAME	A frame error has been detected.
COM_BREAK	A break condition has been detected.
COM_TXB_EMPTY	The transmit hold register is empty.
COM_TX_SHIFT_EMPTY	The transmit shift register is empty.

All error bits (COM_OVERRUN, COM_PARITY, COM_FRAME, and COM_BREAK) are cleared after they have been read once. Since RTCom's interrupt handler also reads the line status register, these can never be read with COMLineStatus if interrupt-driven communication is used.

Function COMSendCharPolled

Down Function COMModemStatus