/* Copyright (C) 2012 by Jacob Alexander * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ // ----- Includes ----- // AVR Includes #include #include #include // Project Includes #include #include // Local Includes #include "scan_loop.h" // ----- Defines ----- // Pinout Defines #define DATA_PORT PORTC #define DATA_DDR DDRC #define DATA_PIN 7 #define DATA_OUT PINC #define CLOCK_PORT PORTC #define CLOCK_DDR DDRC #define CLOCK_PIN 6 #define RESET_PORT PORTF #define RESET_DDR DDRF #define RESET_PIN 7 // ----- Macros ----- // Make sure we haven't overflowed the buffer #define bufferAdd(byte) \ if ( KeyIndex_BufferUsed < KEYBOARD_BUFFER ) \ KeyIndex_Buffer[KeyIndex_BufferUsed++] = byte // ----- Variables ----- // Buffer used to inform the macro processing module which keys have been detected as pressed volatile uint8_t KeyIndex_Buffer[KEYBOARD_BUFFER]; volatile uint8_t KeyIndex_BufferUsed; volatile uint8_t KeyIndex_Add_InputSignal; // Used to pass the (click/input value) to the keyboard for the clicker volatile uint8_t currentWaveState = 0; volatile uint8_t currentWaveDone = 0; volatile uint8_t positionCounter = 0; // Buffer Signals volatile uint8_t BufferReadyToClear; // ----- Function Declarations ----- void processKeyValue( uint8_t keyValue ); void removeKeyValue( uint8_t keyValue ); // ----- Interrupt Functions ----- // Generates a constant external clock ISR( TIMER1_COMPA_vect ) { if ( currentWaveState ) { CLOCK_PORT &= ~(1 << CLOCK_PIN); currentWaveState--; // Keeps track of the clock value (for direct clock output) currentWaveDone--; // Keeps track of whether the current falling edge has been processed positionCounter++; // Counts the number of falling edges, reset is done by the controlling section (reset, or main scan) } else { CLOCK_PORT |= (1 << CLOCK_PIN); currentWaveState++; } } // ----- Functions ----- // Setup inline void scan_setup() { // Setup Timer Pulse (16 bit) // TODO Clock can be adjusted to whatever (read chip datasheets for limits) // This seems like a good scan speed, as there don't seem to be any periodic // de-synchronization events, and is fast enough for scanning keys // Anything much more (100k baud), tends to cause a lot of de-synchronization // 16 MHz / (2 * Prescaler * (1 + OCR1A)) = 10k baud // Prescaler is 1 cli(); TCCR1B = 0x09; OCR1AH = 0x03; OCR1AL = 0x1F; TIMSK1 = (1 << OCIE1A); CLOCK_DDR = (1 << CLOCK_PIN); sei(); // Initially buffer doesn't need to be cleared (it's empty...) BufferReadyToClear = 0; // Reset the keyboard before scanning, we might be in a wierd state scan_resetKeyboard(); } // Main Detection Loop // Since this function is non-interruptable, we can do checks here on what stage of the // output clock we are at (0 or 1) // We are looking for a start of packet // If detected, all subsequent bits are then logged into a variable // Once the end of the packet has been detected (always the same length), decode the pressed keys inline uint8_t scan_loop() { // Read on each falling edge/after the falling edge of the clock if ( !currentWaveDone ) { // Sample the current value 50 times // If there is a signal for 40/50 of the values, then it is active // This works as a very simple debouncing mechanism // XXX Could be done more intelligently: // Take into account the frequency of the clock + overhead, and space out the reads // Or do something like "dual edge" statistics, where you query the stats from both rising and falling edges // then make a decision (probably won't do much better against the last source of noise, but would do well for debouncing) uint8_t total = 0; uint8_t c = 0; for ( ; c < 50; c++ ) if ( DATA_OUT & (1 << DATA_PIN) ) total++; // Only use as a valid signal if ( total >= 40 ) { // Reset the scan counter, all the keys have been iterated over // Ideally this should reset at 128, however // due to noise in the cabling, this often moves around // The minimum this can possibly set to is 124 as there // are keys to service at 123 (0x78) // Usually, unless there is lots of interference, // this should limit most of the noise. if ( positionCounter >= 124 ) { positionCounter = 0; // Clear key buffer KeyIndex_BufferUsed = 0; } // Key Press Detected else { char tmp[15]; hexToStr( positionCounter, tmp ); dPrintStrsNL( "Key: ", tmp ); bufferAdd( positionCounter ); } } // Wait until the next falling clock edge for the next DATA scan currentWaveDone++; } // Check if the clock de-synchronized // And reset if ( positionCounter > 128 ) { char tmp[15]; hexToStr( positionCounter, tmp ); erro_dPrint( "De-synchronization detected at: ", tmp ); errorLED( 1 ); positionCounter = 0; KeyIndex_BufferUsed = 0; // A keyboard reset requires interrupts to be enabled sei(); scan_resetKeyboard(); cli(); } // Regardless of what happens, always return 0 return 0; } // Send data uint8_t scan_sendData( uint8_t dataPayload ) { return 0; } // Signal KeyIndex_Buffer that it has been properly read void scan_finishedWithBuffer( void ) { } // Signal that the keys have been properly sent over USB void scan_finishedWithUSBBuffer( void ) { } // Reset/Hold keyboard // NOTE: Does nothing with the HP150 void scan_lockKeyboard( void ) { } // NOTE: Does nothing with the HP150 void scan_unlockKeyboard( void ) { } // Reset Keyboard void scan_resetKeyboard( void ) { info_print("Attempting to synchronize the keyboard, do not press any keys..."); errorLED( 1 ); // Do a proper keyboard reset (flushes the ripple counters) RESET_PORT |= (1 << RESET_PIN); _delay_us(10); RESET_PORT &= ~(1 << RESET_PIN); // Delay main keyboard scanning, until the bit counter is synchronized uint8_t synchronized = 0; while ( !synchronized ) { // Read on each falling edge/after the falling edge of the clock if ( !currentWaveDone ) { // Read the current data value if ( DATA_OUT & (1 << DATA_PIN) ) { // Check if synchronized // There are 128 positions to scan for with the HP150 keyboard protocol if ( positionCounter == 128 ) synchronized = 1; positionCounter = 0; } // Wait until the next falling clock edge for the next DATA scan currentWaveDone++; } } info_print("Keyboard Synchronized!"); }