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Function RTInitCOMPort

RTInitCOMPort initializes a port and prepares it for communication:

int RTInitCOMPort(int Port, 
                  int IOBase, 
                  int IRQ, 
                  int Baudrate, 
                  int Parity, 
                  int StopBits, 
                  int WordLength, 
                  int ReceiveBufferSize, 
                  int SendBufferSize, 
                  int Protocol);

Parameters

Port

RT_COM1, RT_COM2, RT_COM3, or RT_COM4 (0 .. 3).

IOBase

Any 16-bit integer. The array RTDefaultCOMIOBase can be used for 'standard' ports.

IRQ

0 .. 31. The array RTDefaultCOMIRQ can be used for 'standard' ports. Interrupt sharing is only supported for port pairs COM1/COM3 and COM2/COM4. For best performance, individual IRQs are recommended.

Baudrate

50 .. 115200. A baud rate input clock frequency of 1.8432 Mhz (the PCs default) is assumed. If a different value is used by the target, you must scale the baud rate accordingly. See RTLoc: Locating a Program, section COMPort Command for details.

Parity

Values PARITY_NONE, PARITY_ODD, PARITY_EVEN, PARITY_MARK, and PARITY_SPACE (all defined in Rttcom.h and windows.h) are supported.

StopBits

Values 1 and 2 are supported.

WordLength

Values 5, 6, 7 and 8 are supported.

ReceiveBufferSize

Any size between 1 and 2G is supported. The buffer is allocated from the default Win32 process heap.

SendBufferSize

Any size between 1 and 2G is supported. The buffer is allocated from the default Win32 process heap.

Protocol

RT_NO_PROT, RT_XON_XOFF, RT_RTS_CTS, or RT_DTR_DSR.

return value

0 on failure and a value > 0 on success.

Parameters IOBase, IRQ, ReceiveBufferSize, and SendBufferSize are evaluated only the first time InitCOMPort is called for a particular port. Subsequent calls can only be used to change the UART initialization. If InitCOMPort detects a 16550 UART, its FIFO is automatically enabled at trigger level 8.

Serial Port I/O

Function RTCloseCOMPort