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Function COMPortInit

COMPortInit initializes a port:

void COMPortInit(int  Port, 
                 long Baud, 
                 int  Parity, 
                 int  StopBits, 
                 int  WordLength);

COMPortInit sets the port parameters and disables interrupts for the port. If a 16550A UART is detected, its FIFO is automatically enabled at trigger level 8.

Parameters

Port

Must be in the range 0 to COM_MAX_PORTS-1 (37).

Baud

Baud rate for the port. Supported baud rates range from 50 to 115200.

Parity

Must be set to PARITY_NONE, PARITY_ODD, PARITY_EVEN, PARITY_MARK, or PARITY_SPACE.

StopBits

May be set to 1 or 2.

WordLength

Must be in the range 5 to 8.

RTCom assumes the UART uses a clock input of 1.8432MHz (the value commonly used on PCs). If a different input clock frequency is used by the target hardware, the baud rate specified for COMPortInit must be adjusted according to the following formula:

B = (1,843,200 / Clock Frequency) * Baudrate

where B is the value to be supplied for COMPortInit and Baudrate is the effective baud rate to be used.

Example:

The target computer has a 386EX CPU running at 25Mhz and you want to use COM2 (the second internal serial port of the 386EX) at 57600 baud. The input frequency for the serial ports is CLK2 (50Mhz in this example) divided by 4, giving 12.5 MHz. The value required for COMPortInit is:

(1.8432 / 12.5) * 57600 = 8493

Function COMSetIRQ

Function COMHasFIFO