/*
* the clock and data pins can be wired directly to the clk and data pins
* of the PS2 connector. No external parts are needed.
*/
PS2::PS2(int clk, int data)
{
_ps2clk = clk;
_ps2data = data;
gohi(_ps2clk);
gohi(_ps2data);
}
unsigned char PS2::read(void){
unsigned char data=0, bit=1;
gohi(_ps2clk);
gohi(_ps2data);
delayMicroseconds(50);
while(digitalRead(_ps2clk)==HIGH);
delayMicroseconds(5);
while(digitalRead(_ps2clk)==LOW);
for(int i=0; i<8; i++){
while(digitalRead(_ps2clk)==HIGH);
if(digitalRead(_ps2data)==HIGH) data|=bit;
while(digitalRead(_ps2clk)==LOW);
bit=bit<<1;
}
while(digitalRead(_ps2clk)==HIGH);
while(digitalRead(_ps2clk)==LOW);
while(digitalRead(_ps2clk)==HIGH);
while(digitalRead(_ps2clk)==LOW);
golo(_ps2clk);
return data;
}
/*
* read a byte of data from the ps2 device. Ignores parity.
*/
unsigned char PS2::read(void)
{
unsigned char data = 0x00;
unsigned char i;
unsigned char bit = 0x01;
// start clock
gohi(_ps2clk);
gohi(_ps2data);
delayMicroseconds(50);
while (digitalRead(_ps2clk) == HIGH)
;
delayMicroseconds(5); // not sure why.
while (digitalRead(_ps2clk) == LOW)
; // eat start bit
for (i=0; i < 8; i++)
{
while (digitalRead(_ps2clk) == HIGH)
;
if (digitalRead(_ps2data) == HIGH)
{
data = data | bit;
}
while (digitalRead(_ps2clk) == LOW)
;
bit = bit << 1;
}
// eat parity bit, ignore it.
while (digitalRead(_ps2clk) == HIGH)
;
while (digitalRead(_ps2clk) == LOW)
;
// eat stop bit
while (digitalRead(_ps2clk) == HIGH)
;
while (digitalRead(_ps2clk) == LOW)
;
golo(_ps2clk); // hold incoming data
return data;
}
uint8_t PS2dev::read() {
uint8_t data = 0x00;
uint8_t i;
uint8_t bit = 0x01;
uint8_t parity = 1;
// wait for data line to go low
while (digitalRead(_ps2data) == HIGH);
// wait for clock line to go high
while (digitalRead(_ps2clk) == LOW);
delayMicroseconds(CLKHALF);
golo(_ps2clk);
delayMicroseconds(CLKFULL);
gohi(_ps2clk);
delayMicroseconds(CLKHALF);
for (i = 0; i < 8; i++) {
if (digitalRead(_ps2data) == HIGH) data |= bit;
bit = bit << 1;
delayMicroseconds(CLKHALF);
golo(_ps2clk);
delayMicroseconds(CLKFULL);
gohi(_ps2clk);
delayMicroseconds(CLKHALF);
parity = parity ^ (data & 0x01);
}
// we do the delay at the end of the loop, so at this point we have
// already done the delay for the parity bit
// stop bit
delayMicroseconds(CLKHALF);
golo(_ps2clk);
delayMicroseconds(CLKFULL);
gohi(_ps2clk);
delayMicroseconds(CLKHALF);
delayMicroseconds(CLKHALF);
golo(_ps2data);
golo(_ps2clk);
delayMicroseconds(CLKFULL);
gohi(_ps2clk);
delayMicroseconds(CLKHALF);
gohi(_ps2data);
return data;
}
int8_t PS2dev::write(uint8_t data) {
uint8_t i;
uint8_t parity = 1;
DEBUG_PRN_PS2("PS2dev debug: sending ");
DEBUG_PRNLF_PS2(data, HEX);
if (digitalRead(_ps2clk) == LOW) return -1;
if (digitalRead(_ps2data) == LOW) return -2;
golo(_ps2data);
delayMicroseconds(CLKHALF);
// device sends on falling clock
// start bit
golo(_ps2clk);
delayMicroseconds(CLKFULL);
gohi(_ps2clk);
delayMicroseconds(CLKHALF);
// data bits
for (i = 0; i < 8; i++) {
if (data & 0x01) gohi(_ps2data);
else golo(_ps2data);
delayMicroseconds(CLKHALF);
golo(_ps2clk);
delayMicroseconds(CLKFULL);
gohi(_ps2clk);
delayMicroseconds(CLKHALF);
parity = parity ^ (data & 0x01);
data = data >> 1;
}
// parity bit
if (parity) gohi(_ps2data);
else golo(_ps2data);
delayMicroseconds(CLKHALF);
golo(_ps2clk);
delayMicroseconds(CLKFULL);
gohi(_ps2clk);
delayMicroseconds(CLKHALF);
// stop bit
gohi(_ps2data);
delayMicroseconds(CLKHALF);
golo(_ps2clk);
delayMicroseconds(CLKFULL);
gohi(_ps2clk);
delayMicroseconds(CLKHALF);
delayMicroseconds(50);
return 0;
}
/* write a byte to the PS2 device */
void
PS2::write(unsigned char data)
{
unsigned char i;
unsigned char parity = 1;
gohi(_ps2data);
gohi(_ps2clk);
delayMicroseconds(300);
golo(_ps2clk);
delayMicroseconds(300);
golo(_ps2data);
delayMicroseconds(10);
gohi(_ps2clk); // start bit
/* wait for device to take control of clock */
while (digitalRead(_ps2clk) == HIGH)
; // this loop intentionally left blank
// clear to send data
for (i=0; i < 8; i++)
{
if (data & 0x01)
{
gohi(_ps2data);
} else {
golo(_ps2data);
}
// wait for clock
while (digitalRead(_ps2clk) == LOW)
;
while (digitalRead(_ps2clk) == HIGH)
;
parity = parity ^ (data & 0x01);
data = data >> 1;
}
// parity bit
if (parity)
{
gohi(_ps2data);
} else {
golo(_ps2data);
}
// clock cycle - like ack.
while (digitalRead(_ps2clk) == LOW)
;
while (digitalRead(_ps2clk) == HIGH)
;
// stop bit
gohi(_ps2data);
delayMicroseconds(50);
while (digitalRead(_ps2clk) == HIGH)
;
// mode switch
while ((digitalRead(_ps2clk) == LOW) || (digitalRead(_ps2data) == LOW))
;
// hold up incoming data
golo(_ps2clk);
}
void PS2::write(unsigned char data){
unsigned char parity=1;
gohi(_ps2data);
gohi(_ps2clk);
delayMicroseconds(300);
golo(_ps2clk);
delayMicroseconds(300);
golo(_ps2data);
delayMicroseconds(10);
gohi(_ps2clk);
while(digitalRead(_ps2clk)==HIGH);
for(int i=0; i<8; i++){
if(data&0x01) gohi(_ps2data);
else golo(_ps2data);
while(digitalRead(_ps2clk)==LOW);
while(digitalRead(_ps2clk)==HIGH);
parity^=(data&0x01);
data=data>>1;
}
if(parity) gohi(_ps2data);
else golo(_ps2data);
while(digitalRead(_ps2clk)==LOW);
while(digitalRead(_ps2clk)==HIGH);
gohi(_ps2data);
delayMicroseconds(50);
while(digitalRead(_ps2clk)==HIGH);
while((digitalRead(_ps2clk)==LOW)||(digitalRead(_ps2data)==LOW));
golo(_ps2clk);
}
int PS2dev::write(unsigned char data)
{
unsigned char i;
unsigned char parity = 1;
// Serial.print("sending ");
//Serial.println(data,HEX);
if (digitalRead(_ps2clk) == LOW) {
return -1;
}
if (digitalRead(_ps2data) == LOW) {
return -2;
}
golo(_ps2data);
delayMicroseconds(CLKHALF);
// device sends on falling clock
golo(_ps2clk); // start bit
delayMicroseconds(CLKFULL);
gohi(_ps2clk);
delayMicroseconds(CLKHALF);
for (i=0; i < 8; i++)
{
if (data & 0x01)
{
gohi(_ps2data);
} else {
golo(_ps2data);
}
delayMicroseconds(CLKHALF);
golo(_ps2clk);
delayMicroseconds(CLKFULL);
gohi(_ps2clk);
delayMicroseconds(CLKHALF);
parity = parity ^ (data & 0x01);
data = data >> 1;
}
// parity bit
if (parity)
{
gohi(_ps2data);
} else {
golo(_ps2data);
}
delayMicroseconds(CLKHALF);
golo(_ps2clk);
delayMicroseconds(CLKFULL);
gohi(_ps2clk);
delayMicroseconds(CLKHALF);
// stop bit
gohi(_ps2data);
delayMicroseconds(CLKHALF);
golo(_ps2clk);
delayMicroseconds(CLKFULL);
gohi(_ps2clk);
delayMicroseconds(CLKHALF);
delayMicroseconds(50);
return 0;
}
int PS2dev::read(unsigned char * value)
{
unsigned char data = 0x00;
unsigned char i;
unsigned char bit = 0x01;
unsigned char parity = 1;
//wait for data line to go low
while (digitalRead(_ps2data) == HIGH) {
}
//wait for clock line to go high
while (digitalRead(_ps2clk) == LOW) {
}
delayMicroseconds(CLKHALF);
golo(_ps2clk);
delayMicroseconds(CLKFULL);
gohi(_ps2clk);
delayMicroseconds(CLKHALF);
for (i=0; i < 8; i++)
{
if (digitalRead(_ps2data) == HIGH)
{
data = data | bit;
} else {
}
bit = bit << 1;
delayMicroseconds(CLKHALF);
golo(_ps2clk);
delayMicroseconds(CLKFULL);
gohi(_ps2clk);
delayMicroseconds(CLKHALF);
parity = parity ^ (data & 0x01);
}
// we do the delay at the end of the loop, so at this point we have
// already done the delay for the parity bit
// stop bit
delayMicroseconds(CLKHALF);
golo(_ps2clk);
delayMicroseconds(CLKFULL);
gohi(_ps2clk);
delayMicroseconds(CLKHALF);
delayMicroseconds(CLKHALF);
golo(_ps2data);
golo(_ps2clk);
delayMicroseconds(CLKFULL);
gohi(_ps2clk);
delayMicroseconds(CLKHALF);
gohi(_ps2data);
*value = data;
return 0;
}
/*
* the clock and data pins can be wired directly to the clk and data pins
* of the PS2 connector. No external parts are needed.
*/
PS2dev::PS2dev(uint8_t clockPin, uint8_t dataPin) {
_ps2clk = clockPin;
_ps2data = dataPin;
gohi(_ps2clk);
gohi(_ps2data);
}