582 lines
24 KiB
Arduino
582 lines
24 KiB
Arduino
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//
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// This software interfaces a Teensy 3.2 with a PS/2 laptop touchpad.
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// The touchpad is commanded to be in Stream Mode (not remote mode).
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// This causes the touchpad to send data when ever it detects finger movement.
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// The ps/2 code uses the USB PJRC Mouse functions at www.pjrc.com/teensy/td_mouse.html
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// The ps/2 code has a watchdog timer so the code can't hang if a clock edge is missed.
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// In the Arduino IDE, select Tools, Teensy 3.2. Also under Tools, select Keyboard+Mouse+Joystick
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//
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// Revision History
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// Rev 1.0 - Aug 1, 2020 - Original Release
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//
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// The touchpad ps/2 data and clock lines are connected to the following Teensy I/O pins
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#define TP_DATA 0
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#define TP_CLK 1
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// Teensy LED will be turned ON to show if errors are detected during initialization or during normal use
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#define ERROR_LED 13
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//
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// Declare variables that will be used by functions
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boolean init_error = LOW; // set high if initialization detects an error
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boolean bit_error = LOW; // set high if main loop detects an error
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char mstat; // touchpad status 8 bit register = Y overflow, X overflow, Y sign bit, X sign bit, Always 1, Middle Btn, Right Btn, Left Btn
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char mx; // touchpad x movement = 8 data bits. The sign bit is in the status register to
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// make a 9 bit 2's complement value. Left to right on the touchpad gives a positive value.
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char my; // touchpad y movement also 8 bits plus sign bit in status reg. Touchpad movement away from the user gives a positive value.
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//
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// Function to set a pin to high impedance (acts like open drain output)
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void go_z(int pin)
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{
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pinMode(pin, INPUT);
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digitalWrite(pin, HIGH);
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}
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//
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// Function to set a pin as an input with a pullup
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void go_pu(int pin)
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{
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pinMode(pin, INPUT_PULLUP);
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digitalWrite(pin, HIGH);
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}
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//
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// Function to set a pin to a logic low
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void go_0(int pin)
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{
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pinMode(pin, OUTPUT);
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digitalWrite(pin, LOW);
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}
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//
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// Function to set a pin to a logic high
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void go_1(int pin)
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{
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pinMode(pin, OUTPUT);
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digitalWrite(pin, HIGH);
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}
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//
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// *****************Functions for Touchpad***************************
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//
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// Function to send the touchpad a byte of data (command)
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//
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void tp_write(char send_data)
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{
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unsigned int timeout = 200; // breakout of loop if watchdog over this value in msec
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elapsedMillis watchdog; // zero the watchdog timer clock
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char odd_parity = 0; // clear parity bit count
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// Enable the PS/2 bus by floating the clock and data
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go_pu(TP_CLK); //
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go_pu(TP_DATA); //
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delayMicroseconds(250); // wait before requesting the bus
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go_0(TP_CLK); // Send the Clock line low to request to transmit data
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delayMicroseconds(100); // wait for 100 microseconds per bus spec
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go_0(TP_DATA); // Send the Data line low (the start bit)
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delayMicroseconds(1); //
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go_pu(TP_CLK); // Release the Clock line so it is pulled high
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delayMicroseconds(1); // give some time to let the clock line go high
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while (digitalRead(TP_CLK) == HIGH) { // loop until the clock goes low
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if (watchdog >= timeout) { //check for infinite loop because tp did not respond
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init_error = HIGH;
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break; // break out of infinite loop
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}
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}
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// send the 8 bits of send_data
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for (int j=0; j<8; j++) {
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if (send_data & 1) { //check if lsb is set
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go_pu(TP_DATA); // send a 1 to TP
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odd_parity = odd_parity + 1; // keep running total of 1's sent
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}
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else {
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go_0(TP_DATA); // send a 0 to TP
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}
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delayMicroseconds(1); // delay to let the clock settle out
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while (digitalRead(TP_CLK) == LOW) { // loop until the clock goes high
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if (watchdog >= timeout) { //check for infinite loop
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init_error = HIGH;
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break; // break out of infinite loop
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}
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}
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delayMicroseconds(1); // delay to let the clock settle out
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while (digitalRead(TP_CLK) == HIGH) { // loop until the clock goes low
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if (watchdog >= timeout) { //check for infinite loop
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init_error = HIGH;
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break; // break out of infinite loop
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}
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}
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send_data = send_data >> 1; // shift data right by 1 to prepare for next loop
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}
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// send the parity bit
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if (odd_parity & 1) { //check if lsb of parity is set
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go_0(TP_DATA); // already odd so send a 0 to TP
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}
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else {
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go_pu(TP_DATA); // send a 1 to TP to make parity odd
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}
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delayMicroseconds(1); // delay to let the clock settle out
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while (digitalRead(TP_CLK) == LOW) { // loop until the clock goes high
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if (watchdog >= timeout) { //check for infinite loop
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init_error = HIGH;
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break; // break out of infinite loop
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}
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}
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delayMicroseconds(1); // delay to let the clock settle out
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while (digitalRead(TP_CLK) == HIGH) { // loop until the clock goes low
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if (watchdog >= timeout) { //check for infinite loop
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init_error = HIGH;
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break; // break out of infinite loop
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}
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}
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go_pu(TP_DATA); // Release the Data line so it goes high as the stop bit
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delayMicroseconds(80); // testing shows delay at least 40us
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while (digitalRead(TP_CLK) == HIGH) { // loop until the clock goes low
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if (watchdog >= timeout) { //check for infinite loop
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init_error = HIGH;
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break; // break out of infinite loop
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}
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}
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delayMicroseconds(1); // wait to let the data settle
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if (digitalRead(TP_DATA)) { // Ack bit s/b low if good transfer
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}
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while ((digitalRead(TP_CLK) == LOW) || (digitalRead(TP_DATA) == LOW)) { // loop if clock or data are low
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if (watchdog >= timeout) { //check for infinite loop
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init_error = HIGH;
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break; // break out of infinite loop
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}
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}
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// Inhibit the bus so the tp only talks when we're listening
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go_0(TP_CLK);
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}
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//
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// Function to get a byte of data from the touchpad
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//
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char tp_read(void)
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{
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unsigned int timeout = 200; // breakout of loop if over this value in msec
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elapsedMillis watchdog; // zero the watchdog timer clock
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char rcv_data = 0; // initialize to zero
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char mask = 1; // shift a 1 across the 8 bits to select where to load the data
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char rcv_parity = 0; // count the ones received
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go_pu(TP_CLK); // release the clock
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go_pu(TP_DATA); // release the data
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delayMicroseconds(5); // delay to let clock go high
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while (digitalRead(TP_CLK) == HIGH) { // loop until the clock goes low
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if (watchdog >= timeout) { //check for infinite loop
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init_error = HIGH;
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break; // break out of infinite loop
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}
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}
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if (digitalRead(TP_DATA)) { // Start bit s/b low from tp
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// start bit not correct - put error handler here if desired
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}
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delayMicroseconds(1); // delay to let the clock settle out
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while (digitalRead(TP_CLK) == LOW) { // loop until the clock goes high
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if (watchdog >= timeout) { //check for infinite loop
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init_error = HIGH;
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break; // break out of infinite loop
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}
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}
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for (int k=0; k<8; k++) {
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delayMicroseconds(1); // delay to let the clock settle out
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while (digitalRead(TP_CLK) == HIGH) { // loop until the clock goes low
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if (watchdog >= timeout) { //check for infinite loop
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init_error = HIGH;
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break; // break out of infinite loop
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}
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}
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if (digitalRead(TP_DATA)) { // check if data is high
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rcv_data = rcv_data | mask; // set the appropriate bit in the rcv data
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rcv_parity++; // increment the parity bit counter
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}
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mask = mask << 1;
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delayMicroseconds(1); // delay to let the clock settle out
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while (digitalRead(TP_CLK) == LOW) { // loop until the clock goes high
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if (watchdog >= timeout) { //check for infinite loop
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init_error = HIGH;
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break; // break out of infinite loop
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}
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}
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}
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// receive parity
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delayMicroseconds(1); // delay to let the clock settle out
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while (digitalRead(TP_CLK) == HIGH) { // loop until the clock goes low
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if (watchdog >= timeout) { //check for infinite loop
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init_error = HIGH;
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break; // break out of infinite loop
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}
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}
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if (digitalRead(TP_DATA)) { // check if received parity is high
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rcv_parity++; // increment the parity bit counter
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}
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rcv_parity = rcv_parity & 1; // mask off all bits except the lsb
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if (rcv_parity == 0) { // check for bad (even) parity
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init_error = HIGH;
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}
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delayMicroseconds(1); // delay to let the clock settle out
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while (digitalRead(TP_CLK) == LOW) { // loop until the clock goes high
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if (watchdog >= timeout) { //check for infinite loop
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init_error = HIGH;
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break; // break out of infinite loop
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}
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}
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// stop bit
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delayMicroseconds(1); // delay to let the clock settle out
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while (digitalRead(TP_CLK) == HIGH) { // loop until the clock goes low
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if (watchdog >= timeout) { //check for infinite loop
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init_error = HIGH;
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break; // break out of infinite loop
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}
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}
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if (digitalRead(TP_DATA) == LOW) { // check if stop bit is bad (low)
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// send bad stop bit to future error handler
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}
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delayMicroseconds(1); // delay to let the clock settle out
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while (digitalRead(TP_CLK) == LOW) { // loop until the clock goes high
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if (watchdog >= timeout) { //check for infinite loop
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init_error = HIGH;
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break; // break out of infinite loop
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}
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}
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// Inhibit the bus so the tp only talks when we're listening
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go_0(TP_CLK);
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return rcv_data; // pass the received data back
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}
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//
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// Function to decode 3 bytes of data from the touchpad = status, X Delta, Y Delta
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//
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void tp_packet(void)
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{
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// ******************************Receive Byte 0 = Status***********************
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char rcv_data = 0; // initialize to zero
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char mask = 1; // shift a 1 across the 8 bits to select where to load the data
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char rcv_parity = 0; // count the ones received
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go_pu(TP_CLK); // release the clock
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go_pu(TP_DATA); // release the data
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delayMicroseconds(5); // delay to let clock go high
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while (digitalRead(TP_CLK) == HIGH) { // loop until the clock goes low
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}
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if (digitalRead(TP_DATA)) { // Start bit s/b low from tp
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// start bit not correct - put error handler here if desired
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}
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delayMicroseconds(1); // delay to let the clock settle out
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while (digitalRead(TP_CLK) == LOW) { // loop until the clock goes high
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}
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for (int k=0; k<8; k++) {
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delayMicroseconds(1); // delay to let the clock settle out
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while (digitalRead(TP_CLK) == HIGH) { // loop until the clock goes low
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}
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if (digitalRead(TP_DATA)) { // check if data is high
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rcv_data = rcv_data | mask; // set the appropriate bit in the rcv data
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rcv_parity++; // increment the parity bit counter
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}
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mask = mask << 1;
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delayMicroseconds(1); // delay to let the clock settle out
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while (digitalRead(TP_CLK) == LOW) { // loop until the clock goes high
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}
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}
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// receive parity
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delayMicroseconds(1); // delay to let the clock settle out
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while (digitalRead(TP_CLK) == HIGH) { // loop until the clock goes low
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}
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if (digitalRead(TP_DATA)) { // check if received parity is high
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rcv_parity++; // increment the parity bit counter
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}
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rcv_parity = rcv_parity & 1; // mask off all bits except the lsb
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if (rcv_parity == 0) { // check for bad (even) parity
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bit_error = HIGH;
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}
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delayMicroseconds(1); // delay to let the clock settle out
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while (digitalRead(TP_CLK) == LOW) { // loop until the clock goes high
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}
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// stop bit
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delayMicroseconds(1); // delay to let the clock settle out
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while (digitalRead(TP_CLK) == HIGH) { // loop until the clock goes low
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}
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if (digitalRead(TP_DATA) == LOW) { // check if stop bit is bad (low)
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bit_error = HIGH;
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}
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delayMicroseconds(1); // delay to let the clock settle out
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while (digitalRead(TP_CLK) == LOW) { // loop until the clock goes high
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}
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mstat = rcv_data; // save data result in status byte
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// ******************************Receive Byte 1 = Delta X**************************
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rcv_data = 0; // initialize to zero
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mask = 1; // shift a 1 across the 8 bits to select where to load the data
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rcv_parity = 0; // count the ones received
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delayMicroseconds(5); // delay to let the clock stop ringing
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while (digitalRead(TP_CLK) == HIGH) { // loop until the clock goes low
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}
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if (digitalRead(TP_DATA)) { // Start bit s/b low from tp
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// start bit not correct - put error handler here if desired
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}
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delayMicroseconds(1); // delay to let the clock settle out
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while (digitalRead(TP_CLK) == LOW) { // loop until the clock goes high
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}
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for (int k=0; k<8; k++) {
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delayMicroseconds(1); // delay to let the clock settle out
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while (digitalRead(TP_CLK) == HIGH) { // loop until the clock goes low
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}
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if (digitalRead(TP_DATA)) { // check if data is high
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rcv_data = rcv_data | mask; // set the appropriate bit in the rcv data
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rcv_parity++; // increment the parity bit counter
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}
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mask = mask << 1;
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delayMicroseconds(1); // delay to let the clock settle out
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while (digitalRead(TP_CLK) == LOW) { // loop until the clock goes high
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}
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}
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// receive parity
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delayMicroseconds(1); // delay to let the clock settle out
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while (digitalRead(TP_CLK) == HIGH) { // loop until the clock goes low
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}
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if (digitalRead(TP_DATA)) { // check if received parity is high
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rcv_parity++; // increment the parity bit counter
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}
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rcv_parity = rcv_parity & 1; // mask off all bits except the lsb
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if (rcv_parity == 0) { // check for bad (even) parity
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bit_error = HIGH;
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}
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delayMicroseconds(1); // delay to let the clock settle out
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while (digitalRead(TP_CLK) == LOW) { // loop until the clock goes high
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}
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// stop bit
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delayMicroseconds(1); // delay to let the clock settle out
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while (digitalRead(TP_CLK) == HIGH) { // loop until the clock goes low
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}
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if (digitalRead(TP_DATA) == LOW) { // check if stop bit is bad (low)
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bit_error = HIGH;
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}
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delayMicroseconds(1); // delay to let the clock settle out
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while (digitalRead(TP_CLK) == LOW) { // loop until the clock goes high
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}
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mx = rcv_data; // save data result in delta x byte
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// Receive Byte 1 = Delta Y
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// ******************************Receive Byte 2 = Delta Y**************************
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rcv_data = 0; // initialize to zero
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mask = 1; // shift a 1 across the 8 bits to select where to load the data
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rcv_parity = 0; // count the ones received
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delayMicroseconds(5); // delay to let the clock stop ringing
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while (digitalRead(TP_CLK) == HIGH) { // loop until the clock goes low
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}
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if (digitalRead(TP_DATA)) { // Start bit s/b low from tp
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// start bit not correct - put error handler here if desired
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}
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delayMicroseconds(1); // delay to let the clock settle out
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while (digitalRead(TP_CLK) == LOW) { // loop until the clock goes high
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}
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for (int k=0; k<8; k++) {
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delayMicroseconds(1); // delay to let the clock settle out
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while (digitalRead(TP_CLK) == HIGH) { // loop until the clock goes low
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}
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if (digitalRead(TP_DATA)) { // check if data is high
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rcv_data = rcv_data | mask; // set the appropriate bit in the rcv data
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rcv_parity++; // increment the parity bit counter
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}
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mask = mask << 1;
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delayMicroseconds(1); // delay to let the clock settle out
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while (digitalRead(TP_CLK) == LOW) { // loop until the clock goes high
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}
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}
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// receive parity
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delayMicroseconds(1); // delay to let the clock settle out
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while (digitalRead(TP_CLK) == HIGH) { // loop until the clock goes low
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}
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if (digitalRead(TP_DATA)) { // check if received parity is high
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rcv_parity++; // increment the parity bit counter
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}
|
||
|
rcv_parity = rcv_parity & 1; // mask off all bits except the lsb
|
||
|
if (rcv_parity == 0) { // check for bad (even) parity
|
||
|
bit_error = HIGH;
|
||
|
}
|
||
|
delayMicroseconds(1); // delay to let the clock settle out
|
||
|
while (digitalRead(TP_CLK) == LOW) { // loop until the clock goes high
|
||
|
}
|
||
|
// stop bit
|
||
|
delayMicroseconds(1); // delay to let the clock settle out
|
||
|
while (digitalRead(TP_CLK) == HIGH) { // loop until the clock goes low
|
||
|
}
|
||
|
if (digitalRead(TP_DATA) == LOW) { // check if stop bit is bad (low)
|
||
|
bit_error = HIGH;
|
||
|
}
|
||
|
delayMicroseconds(1); // delay to let the clock settle out
|
||
|
while (digitalRead(TP_CLK) == LOW) { // loop until the clock goes high
|
||
|
}
|
||
|
my = rcv_data; // save data result in delta y byte
|
||
|
//
|
||
|
// Inhibit the bus so the tp only talks when we're listening
|
||
|
go_0(TP_CLK);
|
||
|
}
|
||
|
//
|
||
|
void touchpad_init()
|
||
|
{
|
||
|
init_error = LOW; // start with no error
|
||
|
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
|
||
|
init_error = HIGH;
|
||
|
}
|
||
|
delay(1000); // wait 1 second so tp can run its self diagnostic
|
||
|
// verify proper response from tp
|
||
|
if (tp_read() != 0xaa) { // verify basic assurance test passed
|
||
|
init_error = HIGH;
|
||
|
}
|
||
|
if (tp_read() != 0x00) { // verify basic assurance test passed
|
||
|
init_error = HIGH;
|
||
|
}
|
||
|
// Send touchpad disable code so that the mode byte can be loaded next
|
||
|
tp_write(0xf5); // tp disable
|
||
|
if (tp_read() != 0xfa) { // verify correct ack byte
|
||
|
init_error = HIGH;
|
||
|
}
|
||
|
// Load Mode Byte with 00 using the following special sequence from page 38 of Synaptics Interfaceing Guide.
|
||
|
// Send set resolution to 0 four times followed by a set sample rate to 0x14
|
||
|
// The resolution and sample rate are not actually changed but instead it loads the mode byte.
|
||
|
// #1 set resolution
|
||
|
tp_write(0xe8); // set resolution (actually part of setting mode byte)
|
||
|
if (tp_read() != 0xfa) { // verify correct ack byte
|
||
|
init_error = HIGH;
|
||
|
}
|
||
|
tp_write(0x00); // to zero
|
||
|
if (tp_read() != 0xfa) { // verify correct ack byte
|
||
|
init_error = HIGH;
|
||
|
}
|
||
|
// #2 set resolution (actually part of setting mode byte)
|
||
|
tp_write(0xe8); // set resolution
|
||
|
if (tp_read() != 0xfa) { // verify correct ack byte
|
||
|
init_error = HIGH;
|
||
|
}
|
||
|
tp_write(0x00); // to zero
|
||
|
if (tp_read() != 0xfa) { // verify correct ack byte
|
||
|
init_error = HIGH;
|
||
|
}
|
||
|
// #3 set resolution
|
||
|
tp_write(0xe8); // set resolution
|
||
|
if (tp_read() != 0xfa) { // verify correct ack byte
|
||
|
init_error = HIGH;
|
||
|
}
|
||
|
tp_write(0x00); // to zero
|
||
|
if (tp_read() != 0xfa) { // verify correct ack byte
|
||
|
init_error = HIGH;
|
||
|
}
|
||
|
// #4 set resolution (actually part of setting mode byte)
|
||
|
tp_write(0xe8); // set resolution
|
||
|
if (tp_read() != 0xfa) { // verify correct ack byte
|
||
|
init_error = HIGH;
|
||
|
}
|
||
|
tp_write(0x00); // to zero
|
||
|
if (tp_read() != 0xfa) { // verify correct ack byte
|
||
|
init_error = HIGH;
|
||
|
}
|
||
|
// Set sample rate (actually part of setting mode byte)
|
||
|
tp_write(0xf3); // set sample rate
|
||
|
if (tp_read() != 0xfa) { // verify correct ack byte
|
||
|
init_error = HIGH;
|
||
|
}
|
||
|
tp_write(0x14); // to 14 hex
|
||
|
if (tp_read() != 0xfa) { // verify correct ack byte
|
||
|
init_error = HIGH;
|
||
|
}
|
||
|
// This completes the mode byte load
|
||
|
// set the resolution for real
|
||
|
tp_write(0xe8); // Sending resolution command
|
||
|
if (tp_read() != 0xfa) { // verify correct ack byte
|
||
|
init_error = HIGH;
|
||
|
}
|
||
|
tp_write(0x03); // value of 0x03 = 8 counts/mm resolution (default is 4 counts/mm)
|
||
|
if (tp_read() != 0xfa) { // verify correct ack byte
|
||
|
init_error = HIGH;
|
||
|
}
|
||
|
// set the sample rate for real
|
||
|
tp_write(0xf3); // Sending sample rate command
|
||
|
if (tp_read() != 0xfa) { // verify correct ack byte
|
||
|
init_error = HIGH;
|
||
|
}
|
||
|
tp_write(0x28); // 0x28 = 40 samples per second, the default value used for Synaptics TP
|
||
|
if (tp_read() != 0xfa) { // verify correct ack byte
|
||
|
init_error = HIGH;
|
||
|
}
|
||
|
// Load stream mode command so tp will send data whenever it's available
|
||
|
tp_write(0xea); // stream mode
|
||
|
if (tp_read() != 0xfa) { // verify correct ack byte
|
||
|
init_error = HIGH;
|
||
|
}
|
||
|
// Send touchpad enable code
|
||
|
tp_write(0xf4); // tp enable
|
||
|
if (tp_read() != 0xfa) { // verify correct ack byte
|
||
|
init_error = HIGH;
|
||
|
}
|
||
|
}
|
||
|
//
|
||
|
// ************************************Begin Routine*********************************************************
|
||
|
void setup() {
|
||
|
pinMode(ERROR_LED, OUTPUT); // define teensy I/O 13 as an output
|
||
|
touchpad_init(); // reset tp and check that self diagnostic passed. Put tp in stream mode and enable it
|
||
|
digitalWrite(ERROR_LED, init_error); //LED off means touchpad passed its power up test, ACKed all communications, and never caused a watchdog timeout
|
||
|
delay(5000); // wait 5 seconds to show init_error LED status
|
||
|
digitalWrite(ERROR_LED, LOW); // Turn off LED for 1/2 second
|
||
|
delay(500); // 1/2 second delay
|
||
|
digitalWrite(ERROR_LED, HIGH); // Turn on LED momentarily to indicate code is in main loop
|
||
|
delay(500); // 1/2 second delay
|
||
|
digitalWrite(ERROR_LED, bit_error); // Turn off LED and switch its function to show bit errors in main loop
|
||
|
}
|
||
|
//
|
||
|
// declare and initialize variables
|
||
|
boolean over_flow; // set if x or y movement values are bad due to overflow
|
||
|
boolean left_button = 0; // on/off variable for left button = bit 0 of mstat
|
||
|
boolean right_button = 0; // on/off variable for right button = bit 1 of mstat
|
||
|
boolean old_left_button = 0; // on/off variable for left button status the previous polling cycle
|
||
|
boolean old_right_button = 0; // on/off variable for right button status the previous polling cycle
|
||
|
boolean button_change = 0; // Active high, shows when a touchpad left or right button has changed since last polling cycle
|
||
|
//
|
||
|
// ************************************Main Loop***************************************************************
|
||
|
void loop() {
|
||
|
// Touchpad is enabled and in stream mode
|
||
|
tp_packet(); // this function loops until there is bus activity and then saves data into mstat, mx, and my bytes for USB transmission below.
|
||
|
if (((0x80 & mstat) == 0x80) || ((0x40 & mstat) == 0x40)) { // x or y overflow bits set?
|
||
|
over_flow = 1; // set the overflow flag
|
||
|
}
|
||
|
// change the x data from 9 bit to 8 bit 2's complement by throwing away lsb
|
||
|
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 by throwing away lsb
|
||
|
my = my & 0x7f; // mask off 8th bit
|
||
|
if ((0x20 & mstat) == 0x20) { // move the sign into
|
||
|
my = 0x80 | my; // the 8th bit position
|
||
|
}
|
||
|
// Invert the 8 bit value because y movement in ps/2 format is the opposite direction in touchpad.move function
|
||
|
my = (~my + 0x01); // invert the y data by taking the 2's complement (invert and add 1)
|
||
|
// zero out mx and my if over_flow is detected because the data is garbage
|
||
|
if (over_flow) {
|
||
|
mx = 0x00;
|
||
|
my = 0x00;
|
||
|
bit_error = HIGH; // flag an error
|
||
|
}
|
||
|
// Send the x and y data back via usb if either one is non-zero
|
||
|
if ((mx != 0x00) || (my != 0x00)) {
|
||
|
Mouse.move(mx,my);
|
||
|
}
|
||
|
//
|
||
|
// pull out the left and right button status bits from the mstat byte
|
||
|
if ((0x01 & mstat) == 0x01) { // is bit 1 set
|
||
|
left_button = 1; // set the left_button status
|
||
|
}
|
||
|
else { // clear the left_button status
|
||
|
left_button = 0;
|
||
|
}
|
||
|
if ((0x02 & mstat) == 0x02) { // is bit 2 set
|
||
|
right_button = 1; // set the right_button status
|
||
|
}
|
||
|
else { // clear the right_button status
|
||
|
right_button = 0;
|
||
|
}
|
||
|
// Determine if the left or right touch pad buttons have changed
|
||
|
button_change = (left_button ^ old_left_button) | (right_button ^ old_right_button);
|
||
|
// Don't send button status if there's no change since last usb button transmission.
|
||
|
if (button_change){
|
||
|
Mouse.set_buttons(left_button, 0, right_button); // send button status
|
||
|
old_left_button = left_button; // remember new button status for next polling cycle
|
||
|
old_right_button = right_button;
|
||
|
}
|
||
|
//
|
||
|
digitalWrite(ERROR_LED, bit_error); // LED is used to show NACK, bad parity, overflow, or bad stop bits. Any error is latched "on"
|
||
|
}
|