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Frank Adams 2019-02-05 08:44:06 -08:00 committed by GitHub
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@ -1,4 +1,4 @@
/* Copyright 2018 Frank Adams
/* Copyright 2019 Frank Adams
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
@ -17,6 +17,7 @@
// Revision History
// Rev 1.0 - Nov 23, 2018 - Original Release
// Rev 1.1 - Dec 2, 2018 - Replaced ps/2 trackpoint code from playground arduino with my own code
// Rev 1.2 - Feb 2, 2019 - Changed the error routine and added an error LED
//
// This code has been tested on the touchpad from an HP Pavilion DV9000
// Touchpad part number 920-000702-04 Rev A
@ -34,25 +35,42 @@
// In the Arduino IDE, select Tools, Teensy 3.2. Also under Tools, select Keyboard+Mouse+Joystick
//
// The touchpad ps/2 data and clock lines are connected to the following Teensy I/O pins
#define TP_DATA 27
#define TP_CLK 30
#define TP_DATA 14
#define TP_CLK 23
// Teensy LED will be lit if the touchpad fails to respond properly during initialization
#define ERROR_LED 13
//
// Declare variable that will be used by functions
boolean touchpad_error = LOW; // sent high when touch pad routine times out
//
// Function to float a pin and let the pull-up or Touchpad determine the logic level
// Function to set a pin to high impedance (acts like open drain output)
void go_z(int pin)
{
pinMode(pin, INPUT); // make the pin an input so it floats
pinMode(pin, INPUT);
digitalWrite(pin, HIGH);
}
// function to drive a pin to a logic low
//
// Function to set a pin as an input with a pullup
void go_pu(int pin)
{
pinMode(pin, INPUT_PULLUP);
digitalWrite(pin, HIGH);
}
//
// Function to send a pin to a logic low
void go_0(int pin)
{
pinMode(pin, OUTPUT);
digitalWrite(pin, LOW);
}
//
// Function to send a pin to a logic high
void go_1(int pin)
{
pinMode(pin, OUTPUT);
digitalWrite(pin, HIGH);
}
//
// *****************Functions for Touchpad***************************
//
// Function to send the touchpad a byte of data (command)
@ -63,25 +81,24 @@ void tp_write(char send_data)
elapsedMillis watchdog; // zero the watchdog timer clock
char odd_parity = 0; // clear parity bit count
// Enable the bus by floating the clock and data
go_z(TP_CLK); //
go_z(TP_DATA); //
go_pu(TP_CLK); //
go_pu(TP_DATA); //
delayMicroseconds(250); // wait before requesting the bus
go_0(TP_CLK); // Send the Clock line low to request to transmit data
delayMicroseconds(100); // wait for 100 microseconds per bus spec
go_0(TP_DATA); // Send the Data line low (the start bit)
delayMicroseconds(1); //
go_z(TP_CLK); // Release the Clock line so it is pulled high
go_pu(TP_CLK); // Release the Clock line so it is pulled high
delayMicroseconds(1); // give some time to let the clock line go high
while (digitalRead(TP_CLK) == HIGH) { // loop until the clock goes low
if (watchdog >= timeout) { //check for infinite loop
touchpad_error = HIGH; // set error flag
break; // break out of infinite loop
}
}
// send the 8 bits of send_data
for (int j=0; j<8; j++) {
if (send_data & 1) { //check if lsb is set
go_z(TP_DATA); // send a 1 to TP
go_pu(TP_DATA); // send a 1 to TP
odd_parity = odd_parity + 1; // keep running total of 1's sent
}
else {
@ -90,14 +107,12 @@ void tp_write(char send_data)
delayMicroseconds(1); // delay to let the clock settle out
while (digitalRead(TP_CLK) == LOW) { // loop until the clock goes high
if (watchdog >= timeout) { //check for infinite loop
touchpad_error = HIGH; // set error flag
break; // break out of infinite loop
}
}
delayMicroseconds(1); // delay to let the clock settle out
while (digitalRead(TP_CLK) == HIGH) { // loop until the clock goes low
if (watchdog >= timeout) { //check for infinite loop
touchpad_error = HIGH; // set error flag
break; // break out of infinite loop
}
}
@ -108,37 +123,32 @@ void tp_write(char send_data)
go_0(TP_DATA); // already odd so send a 0 to TP
}
else {
go_z(TP_DATA); // send a 1 to TP to make parity odd
go_pu(TP_DATA); // send a 1 to TP to make parity odd
}
delayMicroseconds(1); // delay to let the clock settle out
while (digitalRead(TP_CLK) == LOW) { // loop until the clock goes high
if (watchdog >= timeout) { //check for infinite loop
touchpad_error = HIGH; // set error flag
break; // break out of infinite loop
}
}
delayMicroseconds(1); // delay to let the clock settle out
while (digitalRead(TP_CLK) == HIGH) { // loop until the clock goes low
if (watchdog >= timeout) { //check for infinite loop
touchpad_error = HIGH; // set error flag
break; // break out of infinite loop
}
}
go_z(TP_DATA); // Release the Data line so it goes high as the stop bit
go_pu(TP_DATA); // Release the Data line so it goes high as the stop bit
delayMicroseconds(80); // testing shows delay at least 40us
while (digitalRead(TP_CLK) == HIGH) { // loop until the clock goes low
if (watchdog >= timeout) { //check for infinite loop
touchpad_error = HIGH; // set error flag
break; // break out of infinite loop
}
}
delayMicroseconds(1); // wait to let the data settle
if (digitalRead(TP_DATA)) { // Ack bit s/b low if good transfer
touchpad_error = HIGH; //bad ack bit so set the error flag
}
while ((digitalRead(TP_CLK) == LOW) || (digitalRead(TP_DATA) == LOW)) { // loop if clock or data are low
if (watchdog >= timeout) { //check for infinite loop
touchpad_error = HIGH; // set error flag
break; // break out of infinite loop
}
}
@ -155,22 +165,20 @@ char tp_read(void)
char rcv_data = 0; // initialize to zero
char mask = 1; // shift a 1 across the 8 bits to select where to load the data
char rcv_parity = 0; // count the ones received
go_z(TP_CLK); // release the clock
go_z(TP_DATA); // release the data
go_pu(TP_CLK); // release the clock
go_pu(TP_DATA); // release the data
delayMicroseconds(5); // delay to let clock go high
while (digitalRead(TP_CLK) == HIGH) { // loop until the clock goes low
if (watchdog >= timeout) { //check for infinite loop
touchpad_error = HIGH; // set error flag
break; // break out of infinite loop
}
}
if (digitalRead(TP_DATA)) { // Start bit s/b low from tp
touchpad_error = HIGH; // No start bit so set the error flag
// start bit not correct - put error handler here if desired
}
delayMicroseconds(1); // delay to let the clock settle out
while (digitalRead(TP_CLK) == LOW) { // loop until the clock goes high
if (watchdog >= timeout) { //check for infinite loop
touchpad_error = HIGH; // set error flag
break; // break out of infinite loop
}
}
@ -178,7 +186,6 @@ char tp_read(void)
delayMicroseconds(1); // delay to let the clock settle out
while (digitalRead(TP_CLK) == HIGH) { // loop until the clock goes low
if (watchdog >= timeout) { //check for infinite loop
touchpad_error = HIGH; // set error flag
break; // break out of infinite loop
}
}
@ -190,7 +197,6 @@ char tp_read(void)
delayMicroseconds(1); // delay to let the clock settle out
while (digitalRead(TP_CLK) == LOW) { // loop until the clock goes high
if (watchdog >= timeout) { //check for infinite loop
touchpad_error = HIGH; // set error flag
break; // break out of infinite loop
}
}
@ -199,7 +205,6 @@ char tp_read(void)
delayMicroseconds(1); // delay to let the clock settle out
while (digitalRead(TP_CLK) == HIGH) { // loop until the clock goes low
if (watchdog >= timeout) { //check for infinite loop
touchpad_error = HIGH; // set error flag
break; // break out of infinite loop
}
}
@ -208,12 +213,11 @@ char tp_read(void)
}
rcv_parity = rcv_parity & 1; // mask off all bits except the lsb
if (rcv_parity == 0) { // check for bad (even) parity
touchpad_error = HIGH; //bad parity so set the error flag
// bad parity - pass to future error handler
}
delayMicroseconds(1); // delay to let the clock settle out
while (digitalRead(TP_CLK) == LOW) { // loop until the clock goes high
if (watchdog >= timeout) { //check for infinite loop
touchpad_error = HIGH; // set error flag
break; // break out of infinite loop
}
}
@ -221,17 +225,15 @@ char tp_read(void)
delayMicroseconds(1); // delay to let the clock settle out
while (digitalRead(TP_CLK) == HIGH) { // loop until the clock goes low
if (watchdog >= timeout) { //check for infinite loop
touchpad_error = HIGH; // set error flag
break; // break out of infinite loop
}
}
if (digitalRead(TP_DATA) == LOW) { // check if stop bit is bad (low)
touchpad_error = HIGH; //bad stop bit so set the error flag
// send bad stop bit to future error handler
}
delayMicroseconds(1); // delay to let the clock settle out
while (digitalRead(TP_CLK) == LOW) { // loop until the clock goes high
if (watchdog >= timeout) { //check for infinite loop
touchpad_error = HIGH; // set error flag
break; // break out of infinite loop
}
}
@ -243,19 +245,19 @@ char tp_read(void)
void touchpad_init()
{
touchpad_error = LOW; // start with no error
go_z(TP_CLK); // float the clock and data to touchpad
go_z(TP_DATA);
go_pu(TP_CLK); // float the clock and data to touchpad
go_pu(TP_DATA);
// Sending reset command to touchpad
tp_write(0xff);
if (tp_read() != 0xfa) { // verify correct ack byte
touchpad_error = HIGH;
}
delayMicroseconds(100); // give the tp time to run its self diagnostic
delay(350); // wait 350ms so tp can run its self diagnostic
// verify proper response from tp
if (tp_read() != 0xaa) { // verify basic assurance test passed
touchpad_error = HIGH;
}
if (tp_read() != 0x00) { // verify correct device id
if (tp_read() != 0x00) { // verify basic assurance test passed
touchpad_error = HIGH;
}
// increase resolution from 4 counts/mm to 8 counts/mm
@ -272,28 +274,12 @@ void touchpad_init()
if (tp_read() != 0xfa) { // verify correct ack byte
touchpad_error = HIGH;
}
if (touchpad_error == HIGH) { // check for any errors from tp
delayMicroseconds(300); // wait before trying to initialize tp one last time
tp_write(0xff); // send tp reset code
tp_read(); // read but don't look at response from tp
tp_read(); // read but don't look at response from tp
tp_read(); // read but don't look at response from tp
tp_write(0xe8); // Send resolution command
tp_read(); // read but don't look at response from tp
tp_write(0x03); // value of 03 gives 8 counts/mm resolution
tp_read(); // read but don't look at response from tp
tp_write(0xf0); // remote mode
tp_read(); // read but don't look at response from tp
delayMicroseconds(100);
}
}
// ************************************Begin Routine*********************************************************
void setup()
{
touchpad_init(); // reset touchpad, then set it's resolution and put it in remote mode
if (touchpad_error) {
touchpad_init(); // try one more time to initialize the touchpad
}
pinMode(ERROR_LED, OUTPUT); // define teensy I/O 13 as an output
}
// declare and initialize variables
@ -310,12 +296,13 @@ void setup()
// ************************************Main Loop***************************************************************
void loop() {
if (touchpad_error == LOW) { // check if touchpad is present
digitalWrite(ERROR_LED, LOW); // turn off LED on Teensy to show touchpad initialized OK
// poll the touchpad for new movement data
over_flow = 0; // assume no overflow until status is received
touchpad_error = LOW; // start with no error
tp_write(0xeb); // request data
if (tp_read() != 0xfa) { // verify correct ack byte
touchpad_error = HIGH;
// bad ack - pass to future error handler
}
mstat = tp_read(); // save into status variable
mx = tp_read(); // save into x variable
@ -324,15 +311,13 @@ void loop() {
over_flow = 1; // set the overflow flag
}
// change the x data from 9 bit to 8 bit 2's complement
mx = mx >> 1; // convert to 7 bits of data by dividing by 2
mx = mx & 0x7f; // don't allow sign extension
mx = mx & 0x7f; // mask off 8th bit
if ((0x10 & mstat) == 0x10) { // move the sign into
mx = 0x80 | mx; // the 8th bit position
}
// change the y data from 9 bit to 8 bit 2's complement and then take the 2's complement
// because y movement on ps/2 format is opposite of touchpad.move function
my = my >> 1; // convert to 7 bits of data by dividing by 2
my = my & 0x7f; // don't allow sign extension
my = my & 0x7f; // mask off 8th bit
if ((0x20 & mstat) == 0x20) { // move the sign into
my = 0x80 | my; // the 8th bit position
}
@ -348,7 +333,6 @@ void loop() {
}
//
// send the touchpad left and right button status over usb if no error
if (!touchpad_error) {
if ((0x01 & mstat) == 0x01) { // if left button set
left_button = 1;
}
@ -370,6 +354,9 @@ void loop() {
old_left_button = left_button; // remember new button status for next polling cycle
old_right_button = right_button;
}
else {
digitalWrite(ERROR_LED, HIGH);
}
//
// **************************************End of touchpad routine***********************************
//