320 lines
8.2 KiB
C
320 lines
8.2 KiB
C
/* Copyright (C) 2012 by Jacob Alexander
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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// ----- Includes -----
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// AVR Includes
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#include <avr/interrupt.h>
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#include <avr/io.h>
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#include <util/delay.h>
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// Project Includes
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#include <led.h>
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#include <print.h>
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// Local Includes
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#include "scan_loop.h"
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// ----- Defines -----
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// Pinout Defines
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#define DATA_PORT PORTC
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#define DATA_DDR DDRC
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#define DATA_PIN 7
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#define DATA_OUT PINC
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#define CLOCK_PORT PORTC
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#define CLOCK_DDR DDRC
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#define CLOCK_PIN 6
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#define RESET_PORT PORTF
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#define RESET_DDR DDRF
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#define RESET_PIN 7
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// ----- Macros -----
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// Make sure we haven't overflowed the buffer
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#define bufferAdd(byte) \
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if ( KeyIndex_BufferUsed < KEYBOARD_BUFFER ) \
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KeyIndex_Buffer[KeyIndex_BufferUsed++] = byte
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// ----- Variables -----
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// Buffer used to inform the macro processing module which keys have been detected as pressed
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volatile uint8_t KeyIndex_Buffer[KEYBOARD_BUFFER];
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volatile uint8_t KeyIndex_BufferUsed;
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volatile uint8_t KeyIndex_Add_InputSignal; // Used to pass the (click/input value) to the keyboard for the clicker
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volatile uint8_t currentWaveState = 0;
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volatile uint8_t positionCounter = 0;
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volatile uint8_t statePositionCounter = 0;
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volatile uint16_t stateSamplesTotal = 0;
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volatile uint16_t stateSamples = 0;
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// Buffer Signals
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volatile uint8_t BufferReadyToClear;
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// ----- Function Declarations -----
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void processKeyValue( uint8_t keyValue );
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void removeKeyValue( uint8_t keyValue );
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// ----- Interrupt Functions -----
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// Generates a constant external clock
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ISR( TIMER1_COMPA_vect )
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{
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if ( currentWaveState )
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{
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CLOCK_PORT &= ~(1 << CLOCK_PIN);
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currentWaveState--; // Keeps track of the clock value (for direct clock output)
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statePositionCounter = positionCounter;
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positionCounter++; // Counts the number of falling edges, reset is done by the controlling section (reset, or main scan)
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}
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else
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{
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CLOCK_PORT |= (1 << CLOCK_PIN);
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currentWaveState++;
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}
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}
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// ----- Functions -----
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// Setup
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inline void scan_setup()
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{
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// Setup Timer Pulse (16 bit)
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// TODO Clock can be adjusted to whatever (read chip datasheets for limits)
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// This seems like a good scan speed, as there don't seem to be any periodic
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// de-synchronization events, and is fast enough for scanning keys
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// Anything much more (100k baud), tends to cause a lot of de-synchronization
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// 16 MHz / (2 * Prescaler * (1 + OCR1A)) = 10k baud
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// Prescaler is 1
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cli();
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TCCR1B = 0x09;
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OCR1AH = 0x03;
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OCR1AL = 0x1F;
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TIMSK1 = (1 << OCIE1A);
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CLOCK_DDR |= (1 << CLOCK_PIN); // Set the clock pin as an output
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DATA_PORT |= (1 << DATA_PIN); // Pull-up resistor for input the data line
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sei();
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// Initially buffer doesn't need to be cleared (it's empty...)
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BufferReadyToClear = 0;
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// Reset the keyboard before scanning, we might be in a wierd state
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scan_resetKeyboard();
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}
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// Main Detection Loop
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// Since this function is non-interruptable, we can do checks here on what stage of the
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// output clock we are at (0 or 1)
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// We are looking for a start of packet
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// If detected, all subsequent bits are then logged into a variable
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// Once the end of the packet has been detected (always the same length), decode the pressed keys
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inline uint8_t scan_loop()
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{
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// Only use as a valid signal
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// Check if there was a position change
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if ( positionCounter != statePositionCounter )
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{
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// At least 80% of the samples must be valid
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if ( stateSamples * 100 / stateSamplesTotal >= 80 )
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{
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// Reset the scan counter, all the keys have been iterated over
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// Ideally this should reset at 128, however
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// due to noise in the cabling, this often moves around
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// The minimum this can possibly set to is 124 as there
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// are keys to service at 123 (0x78)
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// Usually, unless there is lots of interference,
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// this should limit most of the noise.
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if ( positionCounter >= 124 )
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{
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positionCounter = 0;
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}
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// Key Press Detected
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// - Skip 0x00 to 0x0B (11) for better jitter immunity (as there are no keys mapped to those scancodes)
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else if ( positionCounter > 0x0B )
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{
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char tmp[15];
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hexToStr( positionCounter, tmp );
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dPrintStrsNL( "Key: ", tmp );
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// Make sure there aren't any duplicate keys
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uint8_t c;
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for ( c = 0; c < KeyIndex_BufferUsed; c++ )
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if ( KeyIndex_Buffer[c] == positionCounter )
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break;
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// No duplicate keys, add it to the buffer
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if ( c == KeyIndex_BufferUsed )
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bufferAdd( positionCounter );
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}
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}
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// Remove the key from the buffer
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else if ( positionCounter < 124 && positionCounter > 0x0B )
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{
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// Check for the released key, and shift the other keys lower on the buffer
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uint8_t c;
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for ( c = 0; c < KeyIndex_BufferUsed; c++ )
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{
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// Key to release found
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if ( KeyIndex_Buffer[c] == positionCounter )
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{
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// Shift keys from c position
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for ( uint8_t k = c; k < KeyIndex_BufferUsed - 1; k++ )
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KeyIndex_Buffer[k] = KeyIndex_Buffer[k + 1];
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// Decrement Buffer
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KeyIndex_BufferUsed--;
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break;
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}
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}
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}
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// Clear the state counters
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stateSamples = 0;
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stateSamplesTotal = 0;
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statePositionCounter = positionCounter;
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}
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// Pull in a data sample for this read instance
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if ( DATA_OUT & (1 <<DATA_PIN) )
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stateSamples++;
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stateSamplesTotal++;
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// Check if the clock de-synchronized
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// And reset
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if ( positionCounter > 128 )
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{
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char tmp[15];
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hexToStr( positionCounter, tmp );
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erro_dPrint( "De-synchronization detected at: ", tmp );
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errorLED( 1 );
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positionCounter = 0;
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KeyIndex_BufferUsed = 0;
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// Clear the state counters
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stateSamples = 0;
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stateSamplesTotal = 0;
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// A keyboard reset requires interrupts to be enabled
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sei();
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scan_resetKeyboard();
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cli();
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}
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// Regardless of what happens, always return 0
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return 0;
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}
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// Send data
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uint8_t scan_sendData( uint8_t dataPayload )
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{
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return 0;
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}
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// Signal KeyIndex_Buffer that it has been properly read
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void scan_finishedWithBuffer( uint8_t sentKeys )
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{
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}
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// Signal that the keys have been properly sent over USB
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void scan_finishedWithUSBBuffer( uint8_t sentKeys )
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{
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}
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// Reset/Hold keyboard
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// NOTE: Does nothing with the HP150
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void scan_lockKeyboard( void )
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{
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}
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// NOTE: Does nothing with the HP150
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void scan_unlockKeyboard( void )
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{
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}
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// Reset Keyboard
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void scan_resetKeyboard( void )
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{
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info_print("Attempting to synchronize the keyboard, do not press any keys...");
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errorLED( 1 );
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// Do a proper keyboard reset (flushes the ripple counters)
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RESET_PORT |= (1 << RESET_PIN);
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_delay_us(10);
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RESET_PORT &= ~(1 << RESET_PIN);
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// Delay main keyboard scanning, until the bit counter is synchronized
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uint8_t synchronized = 0;
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while ( !synchronized )
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{
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// Only use as a valid signal
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// Check if there was a position change
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if ( positionCounter != statePositionCounter )
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{
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// At least 80% of the samples must be valid
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if ( stateSamples * 100 / stateSamplesTotal >= 80 )
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{
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// Read the current data value
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if ( DATA_OUT & (1 << DATA_PIN) )
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{
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// Check if synchronized
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// There are 128 positions to scan for with the HP150 keyboard protocol
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if ( positionCounter == 128 )
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synchronized = 1;
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positionCounter = 0;
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}
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}
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// Clear the state counters
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stateSamples = 0;
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stateSamplesTotal = 0;
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statePositionCounter = positionCounter;
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}
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}
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info_print("Keyboard Synchronized!");
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}
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