Intel 386 - Manual (Page 320)

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ASYNCHRONOUS SERIAL I/O UNIT
11.4.1 Asynchronous Serial I/O Unit Code Examples
The code example contains these software routines:
InitSIO Initializes the SIO for asynchronous transfers
SerialReadStr Polled serial read function that reads a specified number of
characters
SerialReadChar Polled serial read function that reads a single character
SerialWriteChar Polled serial write function that writes a single character
SerialWriteStr Polled serial write function that writes out an entire string of
characters
SerialWriteMem Polled serial write function that writes out a specified number of
characters stored in a buffer
Serial0_ISR Template interrupt service routine for SIO_0 interrupts
Service_RBF Service routine for interrupts generated by the Receive Buffer Full
signal
SerialWriteStr_Int Interrupt driven serial write function
Service_TBE Service routine for interrupts generated by the Transmit Buffer
Empty signal
The last software routine shows how to use these functions to enable RBF interrupts on the SIO.
See Appendix C for the included header files.
#include <conio.h>
#include <stdio.h>
#include “80386ex.h”
#include “ev386ex.h”
/* Variable Declarations */
int Tbuffer_index = 0;
char trans_buffer[1024];
char rec_buffer;
/*****************************************************************************
InitSIO:
Description:
Initialization routine for Asynchronous Serial I/O Port.
Parameters:
Unit Unit number of the serial port. 0 for SIO port 0,
1 for SIO port 1.
Mode Defines Parity, number of data bits, number of stop bits--
Reference Serial Line Control register for various