Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Adding 'send' capability along with ability to determine send/receive state. #13

Open
wants to merge 3 commits into
base: master
Choose a base branch
from
Open

Adding 'send' capability along with ability to determine send/receive state. #13

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
a12ac30
Added 'send' method by merging in 2016 code by Peter Hanlon and fixin…
Fran-B Dec 31, 2017
7f12adc
Updated 'send' method to time-out if keyboard does not supply a clock…
Fran-B Jan 5, 2018
69fb0cc
MMerge main 'master' of https://github.com/PaulStoffregen/PS2Keyboard
Fran-B Feb 11, 2018
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
224 changes: 190 additions & 34 deletions PS2Keyboard.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -4,13 +4,17 @@
Written by Christian Weichel <info@32leaves.net>

** Mostly rewritten Paul Stoffregen <paul@pjrc.com> 2010, 2011
** Modified for use beginning with Arduino 13 by L. Abraham Smith, <n3bah@microcompdesign.com> *
** Modified for easy interrup pin assignement on method begin(datapin,irq_pin). Cuningan <cuninganreset@gmail.com> **
** Modified for use beginning with Arduino 13 by L. Abraham Smith, <n3bah@microcompdesign.com> *
** Modified for easy interrupt pin assignment on method begin(datapin,irq_pin). Cuningan <cuninganreset@gmail.com> **
** Modified to provide command send facility. Belliveau <flbgaming@gmail.com> using code by Peter Hanlon <pphanlon@bigpond.net.au> June 2016

for more information you can read the original wiki in arduino.cc
at http://www.arduino.cc/playground/Main/PS2Keyboard
or http://www.pjrc.com/teensy/td_libs_PS2Keyboard.html

Version 2.5 (January 2018)
- Support for sending commands to keyboard and checking state

Version 2.4 (March 2013)
- Support Teensy 3.0, Arduino Due, Arduino Leonardo & other boards
- French keyboard layout, David Chochoi, tchoyyfr at yahoo dot fr
Expand Down Expand Up @@ -53,42 +57,22 @@
#define BUFFER_SIZE 45
static volatile uint8_t buffer[BUFFER_SIZE];
static volatile uint8_t head, tail;

static volatile uint8_t Sending=0;
static volatile uint8_t Receiving=0;
static volatile uint8_t Ack=0;
static volatile uint8_t Parity=0;
static volatile uint8_t Outgoing=0;

static uint8_t DataPin;
static uint8_t IrqPin;
static uint8_t CharBuffer=0;
static uint8_t UTF8next=0;
static const PS2Keymap_t *keymap=NULL;

// The ISR for the external interrupt
void ps2interrupt(void)
static inline bool is_scan_code_avail(void)
{
static uint8_t bitcount=0;
static uint8_t incoming=0;
static uint32_t prev_ms=0;
uint32_t now_ms;
uint8_t n, val;

val = digitalRead(DataPin);
now_ms = millis();
if (now_ms - prev_ms > 250) {
bitcount = 0;
incoming = 0;
}
prev_ms = now_ms;
n = bitcount - 1;
if (n <= 7) {
incoming |= (val << n);
}
bitcount++;
if (bitcount == 11) {
uint8_t i = head + 1;
if (i >= BUFFER_SIZE) i = 0;
if (i != tail) {
buffer[i] = incoming;
head = i;
}
bitcount = 0;
incoming = 0;
}
return (tail != head);
}

static inline uint8_t get_scan_code(void)
Expand All @@ -100,10 +84,169 @@ static inline uint8_t get_scan_code(void)
i++;
if (i >= BUFFER_SIZE) i = 0;
c = buffer[i];
tail = i;

tail = i;
/* Add leading slash for debug output
Serial.print(c, HEX);
Serial.print(" ");
//*/
return c;
}

/* Numbered steps are from http://www.computer-engineering.org/ps2protocol
* Author: Adam Chapweske
* Last Updated: 05/09/03
*
* Steps required overall to send data to a PS/2 device:
*
* 1) Bring the Clock line low for at least 100 microseconds.
* 2) Bring the Data line low.
* 3) Release the Clock line.
* 4) Wait for the device to bring the Clock line low.
*
* Thus transfering control to the interupt handler.
*
* 5) Set/reset the Data line to send the first data bit
* 6) Wait for the device to bring Clock high.
* 7) Wait for the device to bring Clock low.
* 8) Repeat steps 5-7 for the other seven data bits and the parity bit
*
* 9) Release the Data line.
* 10) Wait for the device to bring Data low.
* 11) Wait for the device to bring Clock low.
* 12) Wait for the device to release Data and Clock
*
* After that the keyboard responds with either FA for "okay",
* or FE for "try again".
*/
uint8_t PS2Keyboard::send(uint8_t byteCmd)
{
while (Receiving > 0) // wait until idle
{
// 1100 uSec Max byte Rx time
delayMicroseconds(100);
}
pinMode(IrqPin,OUTPUT);
digitalWrite(IrqPin,LOW);
Sending = 1;
Outgoing = byteCmd;
Ack = 1; // should drop to 0
delayMicroseconds(150); // 100 minimum required
pinMode(DataPin,OUTPUT);
digitalWrite(DataPin,LOW);

// now that send has control, clear the buffer so response is available
clear();

#ifdef INPUT_PULLUP
pinMode(IrqPin, INPUT_PULLUP);
#else
pinMode(IrqPin,INPUT);
digitalWrite(IrqPin,HIGH);
#endif
unsigned long startTime = micros();

while ((Sending > 0) && (2000 > (micros() - startTime)))
{
delayMicroseconds(50);
}
uint8_t result = (Sending > 0) ? SEND_TIMED_OUT : SEND_NOT_ACKED;

if (!Ack) // Send was Ack'ed
{
startTime = micros();
while ((2000 > (micros() - startTime)) && !is_scan_code_avail())
{
delayMicroseconds(50);
}
if (is_scan_code_avail())
{
result = get_scan_code(); // expect Resend or Okay
}
else
{
result = SEND_REPLY_TIMEOUT;
}
}
return(result);
}

// The ISR for the external interrupt
void ps2interrupt(void)
{
static uint8_t bitcount=0;
static uint8_t incoming=0;
static uint32_t prev_ms=0;
uint32_t now_ms;
uint8_t n, val;

now_ms = millis();

if (Sending == 0) { // receiving mode
val = digitalRead(DataPin);
if (now_ms - prev_ms > 250) {
bitcount = 0;
incoming = 0;
Receiving = 1; // receive cycle in progress
}
prev_ms = now_ms;
n = bitcount - 1;
if (n <= 7) {
incoming |= (val << n);
}
bitcount++;
if (bitcount == 11) {
uint8_t i = head + 1;
if (i >= BUFFER_SIZE) i = 0;
if (i != tail) {
buffer[i] = incoming;
head = i;
}
bitcount = 0;
incoming = 0;
Receiving = 0; // receive cycle complete
}
}
else { // sending mode
if (now_ms - prev_ms > 250) {
Sending = 1; // signal "need init"
}
prev_ms = now_ms;
if (Sending == 1) { // Sending mode - initialisation
bitcount = 0;
Parity = 1;
Sending = 2; // Sending mode - body
pinMode(DataPin,OUTPUT);
}
if (bitcount < 8) {
n = bitcount;
val = (Outgoing >> n) & 1;
Parity ^= val;
digitalWrite(DataPin,val);
}
if (bitcount == 8) {
digitalWrite(DataPin,Parity);
}
if (bitcount == 9) {
digitalWrite(DataPin,HIGH); // Stop Bit
#ifdef INPUT_PULLUP
pinMode(DataPin, INPUT_PULLUP);
#else
pinMode(DataPin,INPUT);
#endif
}
if (bitcount == 10) {
Ack = digitalRead(DataPin);
}
bitcount++;
if (bitcount == 11) {
Sending = 0;
bitcount = 0;
//pinMode(DataPin,INPUT);
}
}
}

// http://www.quadibloc.com/comp/scan.htm
// http://www.computer-engineering.org/ps2keyboard/scancodes2.html

Expand Down Expand Up @@ -516,10 +659,12 @@ PS2Keyboard::PS2Keyboard() {
// nothing to do here, begin() does it all
}

void PS2Keyboard::begin(uint8_t data_pin, uint8_t irq_pin, const PS2Keymap_t &map) {
void PS2Keyboard::begin(
uint8_t data_pin, uint8_t irq_pin, const PS2Keymap_t &map) {
uint8_t irq_num=255;

DataPin = data_pin;
IrqPin = irq_pin;
keymap = &map;

// initialize the pins
Expand Down Expand Up @@ -663,9 +808,20 @@ void PS2Keyboard::begin(uint8_t data_pin, uint8_t irq_pin, const PS2Keymap_t &ma

head = 0;
tail = 0;
Receiving = 0;
Sending = 0;
if (irq_num < 255) {
attachInterrupt(irq_num, ps2interrupt, FALLING);
}
}

PS2Keyboard::KeyboardState PS2Keyboard::getState()
{
KeyboardState result;

result.receiving = Receiving;
result.sending = Sending;
result.outgoing = Outgoing;

return result;
}
Loading