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<font size=12>祝大家 新春快乐 技术有成 梦想成真</font>
转载一篇关于PS2键盘的代码和文章：点击此处下载 ourdev_614524JIK2YF.rar(文件大小:505K) (原文件名:PS2_driver.rar)
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/*
ps2key.c:
**************************************************************************************************
* Embedded Systems Building Blocks
* PS/2 Keyboard 104 keys, NumPad driver
*
* Original obtained from www.picant.com, C2C complier web site
* by Julio Cesar Silva Briano, modified by John Leung
*
* Filenmae : ps2key.c
* Programmer : John Leung, www.TechToys.com.hk under Downloads Section.
* Version : Version 1.1 - 17th June 2004
* Remarks : Consult www.beyong.org for PS/2 keyboard protocol
**************************************************************************************************
* DESCRIPTION
* This is a PS/2 keyboard driver for standard 101/104 keyboard or Numerical Keypad
* Application software must include PS2Key.h and PS2ScanCode.h
* PS2Key.h contains hardware port configuration
* PS2ScanCode.h configures if it is a complete 101 keyboard, or just the Numpad
* Two lookup tables PS2KeyUnshifted[] and PS2KeyShifted[] map the PS2Key_Code to ASCII characters
* If it is going to be the Numpad ONLY, PS2KeyUnshifted[] and PS2KeyShifted[] can be undefined to save ROM
* Application must declare the followings (see ps2key.h)
* PS2key.c is PS/2 keyboard driver to handle ordinary PS/2 or AT-style keyboard with mcu
* Global variable PS2Key_Code returns the raw key code of a key
* Key Buffer is defined by constant PS2KEY_BUF_SIZE (in PS2Key.h)
*
* PS2Key_Clk The port address of the PS/2 CLK signal
* PS2Key_Data The port address of the PS/2 Data signal
* PS2Key_BUF_SIZE Size of the PS/2 keyboard buffer
**************************************************************************************************
*/
/*
**************************************************************************************************
* Date: 2 Feb 2006
* Revised for void PS2KeyIntHandler(void), bug reported by CSS forum that, this piece of code
* didn't work for Xtal frequency 4Mhz. This is because the following switch case spent too much
* time
* void PSKeyIntHandler(void){
* ....
case PS2Key_STOP: // Stop bit (PS2Key_STOP = 11)
if (PS2Key_Code==0x12||PS2Key_Code==0x59) // Key=Left shift or right shift
{ if (PS2_BREAKCODE==TRUE)
PS2_SHIFT=FALSE;
else
PS2_SHIFT=TRUE;
}
if (PS2Key_Code==0xF0) // Is a break code!
PS2_BREAKCODE=TRUE; // ignore break code
else if (PS2_BREAKCODE==TRUE)
PS2_BREAKCODE=FALSE;
else
PS2KeyBufIn (PS2Key_Code); // put valid key in buffer
PS2Key_bit_Ix=0;
* ....}
* CHECKING FOR SHIFT KEY OR BREAK KEY SHOULDN'T BE HANDLED UNDER RB0 INTERRUPT ROUTINE!
**************************************************************************************************
*/
/*
**************************************************************************************
* Date 3 Feb 2005
* Bug reported when Xtal = 4MHz. When Xtal = 20MHz, the original code ran OK
* Revision : 1. Change to 4MHz crystal
* 2. Add #use fast_io(b) in main()
* 3. Change A4 -> B1 for PS2Key_Data (for hardware simplicity only)
* 4. The key modification in void PS2KeyIntHandler(void). Previously
* switch (PS2Key_bit_Ix) case... applied but the assembly code
* generated took too long for clock signal detection of keyboard
* Instead of switch, a simple if() else if ... selection employed
* 5. Detection of PS2_BREAKCODE and PS2_SHIFT deleted from
* PS2KeyIntHandler(void) to save interrupt time.
**************************************************************************************
*/
/*
**************************************************************************************************
GLOBAL VARIABLES
**************************************************************************************************
*/
INT8U PS2KeyBuf[PS2KEY_BUF_SIZE]; //PS2 Keyboard buffer, the register to store characters key in
INT8U PS2KeyBufInIx; //Index into PS/2 key buf where next scan code will be inserted
INT8U PS2KeyBufOutIx; //Index into PS/2 key buf where next scan code will be removed
INT8U PS2KeyNRead; //Number of keys read from the PS/2 keyboard
INT8U PS2Key_Code; //Key code from PS/2 keyboard
INT8U PS2Key_bit_Ix; //bit index of the byte stream, Start_bit(1), Parity(10), Stop_bit(11)
BOOLEAN PS2_SHIFT; //TRUE if left or right shift pressed
BOOLEAN PS2_BREAKCODE; //TRUE if a BREAKCODE received
/*
**************************************************************************************************
LOCAL FUNCTION PROTOTYPES
**************************************************************************************************
*/
void PS2KeyBufIn(INT8U code); /* Insert scan code into keyboard buffer */
INT8U PS2KeyDecode(void); /* Function to decode a key stroke */
/*
**************************************************************************************************
* INSERT KEY CHARACTER INTO KEYBOARD BUFFER
* Description: This function inserts a key character into the keyboard buffer from a PS/2 keyboard
**************************************************************************************************
*/
void PS2KeyBufIn (INT8U code)
{
if (PS2KeyNRead < PS2Key_BUF_SIZE) { //make sure that we don't overflow the buffer
PS2KeyNRead++; //Increment the number of keys read
PS2KeyBuf[PS2KeyBufInIx++] = code; //Store the scan code into the buffer
if (PS2KeyBufInIx >= PS2Key_BUF_SIZE) { //Adjust index to the next scan code to put in buffer
PS2KeyBufInIx = 0;
}
}
}
/*
**************************************************************************************************
* DECODE PS/2 KEYBOARD SCAN CODE
* Description: This function is called to determine the key scane code of the PS/2 keyboard
* Arguments: none
* Returns: the key scan code
**************************************************************************************************
*/
INT8U PS2KeyDecode(void)
{
;
}
/*
**************************************************************************************************
* GET KEY
* Description: Get a PS/2 keyboard scan code from the keyboard driver
* Arguments: none
* Returns: !=0xFF is the key scan code of the PS/2 keyboard key pressed
* ==0xFF indicates that there is on key in the PS2KeyBuf[PS2KEY_BUF_SIZE] buffer
**************************************************************************************************
*/
INT8U PS2KeyGetKey (void)
{
INT8U code;
//OS_ENTER_CRITICAL();
if (PS2KeyNRead > 0) { /* See if we have keys in PS2KeyBuf[] */
PS2KeyNRead--; /* Decrement the number of keys in the buffer */
code = PS2KeyBuf[PS2KeyBufOutIx]; /* Get scan code from the buffer */
PS2KeyBufOutIx++;
if (PS2KeyBufOutIx >= PS2Key_BUF_SIZE) {
PS2KeyBufOutIx = 0;
}
//OS_EXIT_CRITICAL();
return (code); /* return the scan code of the key pressed */
} else {
//OS_EXIT_CRITICAL();
return (0xFF); /* No scan codes in buffer, return -1 */
}
}
/*
**************************************************************************************************
* SEND COMMAND
* Description: Send command to the PS/2 keyboard
* Arguments: cmd is the command to send
* $ED Set Status LED's - This command can be used to turn on and off the Num Lock, Caps Lock & Scroll Lock LED's.
* After Sending ED, keyboard will reply with ACK (FA) and wait for another byte which determines their Status.
* Bit 0 controls the Scroll Lock, Bit 1 the Num Lock and Bit 2 the Caps lock. Bits 3 to 7 are ignored.
* $EE Echo - Upon sending a Echo command to the Keyboard, the keyboard should reply with a Echo (EE)
* $F0 Set Scan Code Set. Upon Sending F0, keyboard will reply with ACK (FA) and wait for another byte,
01-03 which determines the Scan Code Used.
Sending 00 as the second byte will return the Scan Code Set currently in Use
* $F3 Set Typematic Repeat Rate. Keyboard will Acknowledge command with FA and wait for second byte,
which determines the Typematic Repeat Rate.
* $F4 Keyboard Enable - Clears the keyboards output buffer, enables Keyboard Scanning and returns an Acknowledgment.
* $F5 Keyboard Disable - Resets the keyboard, disables Keyboard Scanning and returns an Acknowledgment.
* $FE Resend - Upon receipt of the resend command the keyboard will re- transmit the last byte sent.
* $FF Reset - Resets the Keyboard.
* Returns: none
* Remarks: Refer to AN1723 of Motorola for detailed description of Host-to-KBD protocol
* Is NOT working as per 17th June 2004. Should work more on this function.
**************************************************************************************************
*/
void PS2SendComm(INT8U cmd)
{
PS2Key_bit_Ix = 0; //bit index of the byte stream, Start_bit(1), Parity(10), Stop_bit(11), ACK_bit(12)
disable_interrupts(INT_EXT); //disable external interrupt B0 on falling edge
output_low(PS2Key_Clk); //host forces PS2 clock line low.
delay_us(35); //After approx. 35us, the host pulls PS2 data line low
output_low(PS2Key_Data); //This sequence of event signals the keyboard that
//the host is about to transfer a command
delay_us(125); //The clock signal is released and pulled high by the keyboard's pullup
PS2Key_ClkTris = 1; //resisitor after the falling edge of the data signal
/* Transfer of data from host to keyboard will start approx. 1ms after the rising edge of the clock */
/* shift bit to PS2Key_Data on every falling edge of the PS2Key_Clk line */
do
{ while (input(PS2Key_Clk))
; //hold when PS2Key_Clk is high
output_bit(PS2Key_Data, cmd&0x01);
cmd = cmd>>1;
//PS2Key_DataTris=1;
PS2Key_bit_Ix++;
} while(PS2Key_bit_Ix<=12);
PS2Key_bit_Ix = 0;
/* send data from host complete */
PS2Key_DataTris = 1; //release data line, reset to input
ext_int_edge(0, H_TO_L); //set external interrupt to falling edge
enable_interrupts(INT_EXT); //release PS2 KBD clock line. driven high by PS2 KBD
}
/*
**************************************************************************************************
* SEE IF ANY KEY IN BUFFER
* Description: This function checks to see if a key was pressed
* Arguments: none
* Returns: TRUE if a key has been pressed
* FALSE if no key pressed
**************************************************************************************************
*/
BOOLEAN PS2KeyHit(void)
{
BOOLEAN hit;
//OS_ENTER_CRITICAL();
hit = (BOOLEAN)(PS2KeyNRead > 0)? TRUE : FALSE;
//OS_EXIT_CRITICAL();
return(hit);
}
/*
*********************************************************************************************************
* PS2 KEYBOARD DRIVER INITIALIZATION
*
* Description : This function initializes the PS2 driver.
* Arguments : None.
* Returns : None.
*********************************************************************************************************
*/
void PS2KeyInit(void)
{
PS2KeyNRead =0; //Clear the number of keys read
PS2KeyBufInIx =0; //Clear the key codes inserted at the beginning of the buffer
PS2KeyBufOutIx =0; //Clear the key codes removed at the beginning of the buffer
PS2_BREAKCODE =FALSE;
PS2_SHIFT =FALSE;
PS2Key_DataTris =1; //Set Data line an input
PS2Key_ClkTris =1; //Set clock line an input
ext_int_edge(0, H_TO_L); //set external interrupt to falling edge
enable_interrupts(INT_EXT); //enable external interrupt B0
}
/*
*********************************************************************************************************
* PS2 KEYBOARD INTERRUPT HANDLER
* Description: This function is called by an interrupt handler (e.g. B0 EXT INT on falling edge)
* Detect the clock pulse (High_to_Low) for new bit
* Total 11 bits for a complete frame (keyboard -> Host)
* Arguments : none
* Returns : none
* Notes : Put a scan code to PS2KeyBuf[] if a valid byte acquired
* Set PS2KeyNRead then
*********************************************************************************************************
*/
void PS2KeyIntHandler(void)
{
BOOLEAN PS2Key_Data_State; //Temp variable for Data pin, PS2Key_Data_State
BOOLEAN PS2Key_Clk_State;
BOOLEAN PS2Status_Parity; //Parity bit
PS2Key_Data_State = input(PS2Key_Data);
PS2Key_Clk_State = input(PS2Key_Clk);
PS2Key_bit_Ix++;
if (PS2Key_bit_Ix==PS2Key_START)
{ // First bit, PS2Key_START = 1 as defined under ps2key.h
if (PS2Key_Data_State || PS2Key_Clk_State) PS2Key_bit_Ix=0;
// Start bit clock is a high_to_low transition.
// Start bit is a low bit. If data pin or Clk pin high for the Start bit,
// it must be a false trigger from RB0, thus setting PS2Key_bit_Ix=0
PS2Key_Code=0;
PS2Status_Parity=0;
}
else if (PS2Key_bit_Ix==PS2Key_PARITY)
{ // Parity bit, PS2Key_PARITY = 10 as defined under ps2key.h
PS2Status_Parity = PS2Key_Data_State;
}
else if (PS2Key_bit_Ix==PS2Key_STOP)
{ // Stop bit (PS2Key_STOP = 11), put key in buffer
// Put valid byte in PS2KeyBuf[]
PS2KeyBufIn (PS2Key_Code);
PS2Key_bit_Ix=0;
}
else
{ // For all bits from 2, 3...9 (total 8-bit)
PS2Key_Code = PS2Key_Code >> 1;
if (PS2Key_Data_State)
PS2Key_Code = PS2Key_Code | 0x80;
}
}
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发表于 2011-2-3 11:45:09
