outbound.c

嵌入式系统基础课件

#include "libepc.h"
#include "os_cpu.h"
#include "os_cfg.h"
#include "ucos_ii.h"
#include "packet.h"
#include <dos.h>
#include <ctype.h>

OS_EVENT *kybd_queue = NULL ;
void KeyboardISR(void) ;

PRIVATE void KeyboardInit(void) ;

void OutboundThread(void)
	{
	WINDOW *local ;

	/* INITIALIZATION: Paint the local window. Create a	*/
	/* mailbox object to receive keystroke codes from the	*/
	/* keyboard ISR. Initialize the keyboard hardware.	*/
	/* Point interrupt vector 33 at the keyboard ISR.	*/
	/* Unmask the IRQ line in the 8259 PIC.			*/

	local = WindowCreate("Local", 0, 10, 0, 79) ;
	KeyboardInit() ;

	for (;;)
		{
		BYTE8 err, scan_code ;
		char ascii ;

		/* Suspend this thread (let it "sleep") until a	*/
		/* keyboard interrupt posts something to our	*/
		/* mailbox.  But first position the cursor 	*/
		/* at the next character position as a prompt.	*/

		WindowSelect(local) ;
		scan_code = ((unsigned) OSQPend(kybd_queue, 0, &err)) & 0xFF ;
		if (scan_code & 0x80) continue ; /* Key up */

		/* The keyboard ISR just woke us up. scan_code	*/
		/* is the keystroke that occurred. First check	*/
		/* to see if it simply changes state, like caps	*/
		/* lock, shift, ctrl, or alt.  Then convert the	*/
		/* scancode to ascii using the current state.	*/

		if (SetsKybdState(scan_code)) continue ;
		ascii = ScanCode2Ascii(scan_code) & 0xFF ;
		if (!isprint(ascii) && !iscntrl(ascii)) continue ;

		/* Display the character in the local window.	*/

		WindowPutChar(local, ascii) ;

		SendPacket(1, &ascii, 1) ;
		if (ascii == '\r')
			{
			static char linefeed = '\n' ;
			WindowPutChar(local, linefeed) ;
			SendPacket(1, &linefeed, 1) ;
			}
		}
	}

PRIVATE void KeyboardInit(void)
	{
	static void *q[20] ;

	kybd_queue = OSQCreate(q, ENTRIES(q)) ;
	SetISR(IRQ2INT(IRQ_KYBD), KeyboardISR) ;
	outportb(0x21, inportb(0x21) & ~0x02) ;
	}