key.c

基于8051的驱动源码.包括STN LCD driver, I2C driver, 键盘(模拟键盘)驱动,串口驱动,中断应用,部分GDI函数

#include "type.h"
#include "reg52.h"
#include "common.h"
#include "key.h"

typedef struct tagKey
{
	S_BYTE KeyCode : 5;
	S_BYTE pressed : 1;
	S_BYTE reserved : 2;
	S_BYTE counter;
}
S_KEY;

#define KEY_SHORT_COUNT_MAX	50
#define KEY_LONG_COUNT_MAX	250
#define NO_KEY_PRESSED		0x00	
#define KEY_MASK				0xFC


static S_KEY idata gkey;
S_BYTE code KeyMask[] = {0x80, 0x40, 0x20, 0x10, 0x08, 0x04};

static S_BYTE GetKeyPins(void)
{
//	P0 = KEY_MASK;
	return (~P2 & KEY_MASK);
}

static void KeyScan(void)
{
	S_BYTE i;
	S_BYTE key;

	if (gkey.pressed)
		return;
	key = GetKeyPins();
	if (key == 0)
	{
		if (gkey.counter == 0)
			DelayMs(1);
		else if (gkey.counter < KEY_SHORT_COUNT_MAX)
			gkey.KeyCode = KEY_NULL;
		else if (gkey.counter < KEY_LONG_COUNT_MAX)
			gkey.pressed = 1;
		else
		{
			gkey.pressed = 1;
			gkey.KeyCode += KEY_SHORT_END;
		}
		gkey.counter = 0;
		return;	
	}

	for (i = 0; i < sizeof(KeyMask); i++)
		if (key == KeyMask[i])
			break;
	if (i >= sizeof(KeyMask))
		return;

	key = i + KEY_SHORT_BEGIN;
	if (gkey.KeyCode == KEY_NULL)
		gkey.KeyCode = key;
	else if (gkey.KeyCode != key)
	{
		gkey.KeyCode = key;
		gkey.counter = 0;
	}
	if (gkey.counter <= KEY_LONG_COUNT_MAX)
	{
		gkey.counter += 1;
		DelayUs(500);
	}

	return;
}

static S_BYTE _GetKey_(void)
{
	S_BYTE key;

	if (gkey.pressed)
	{
		key = gkey.KeyCode;
		gkey.KeyCode = KEY_NULL;
		gkey.pressed = 0;
		gkey.counter = 0;
		return key;
	}

	return KEY_NULL;
}

S_BYTE GetKey(void)
{
	KeyScan();
	return _GetKey_();
}

S_BOOL PutKey(S_BYTE key)
{
	if (gkey.pressed)
		return S_FALSE;
	
	gkey.pressed = 1;
	gkey.KeyCode = key;
	return S_TRUE;
}

S_BYTE WaitKey(void)
{
	S_BYTE key;

	while (1)
	{
		key = GetKey();
		if (key)
			return key;
		DelayMs(3);
	}
}