503 lines
16 KiB
C
503 lines
16 KiB
C
/*
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Charliplexing.cpp - Using timer2 with 1ms resolution
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Alex Wenger <a.wenger@gmx.de> http://arduinobuch.wordpress.com/
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Matt Mets <mahto@cibomahto.com> http://cibomahto.com/
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Timer init code from MsTimer2 - Javier Valencia <javiervalencia80@gmail.com>
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Misc functions from Benjamin Sonnatg <benjamin@sonntag.fr>
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History:
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2009-12-30 - V0.0 wrote the first version at 26C3/Berlin
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2010-01-01 - V0.1 adding misc utility functions
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(Clear, Vertical, Horizontal) comment are Doxygen complaints now
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2010-05-27 - V0.2 add double-buffer mode
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2010-08-18 - V0.9 Merge brightness and grayscale
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include <math.h>
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#include <avr/interrupt.h>
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#include <util/delay.h>
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#include "Charliplexing.h"
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volatile unsigned int LedSign_tcnt2;
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typedef struct _videoPage {
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uint8_t pixels[SHADES][48]; // TODO: is 48 right?
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} videoPage;
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/* ----------------------------------------------------------------- */
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/** Table for the LED multiplexing cycles
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* Each frame is made of 24 bytes (for the 24 display cycles)
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* There are SHADES frames per buffer in grayscale mode (one for each brigtness)
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* and twice that many to support double-buffered grayscale.
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*/
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videoPage leds[2];
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/// Determines whether the display is in single or double buffer mode
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uint8_t displayMode = SINGLE_BUFFER;
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/// Flag indicating that the display page should be flipped as soon as the
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/// current frame is displayed
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volatile bool videoFlipPage = false;
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/// Pointer to the buffer that is currently being displayed
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videoPage* displayBuffer;
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/// Pointer to the buffer that should currently be drawn to
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videoPage* workBuffer;
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/// Flag indicating that the timer buffer should be flipped as soon as the
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/// current frame is displayed
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volatile bool videoFlipTimer = false;
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// Timer counts to display each page for, plus off time
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typedef struct timerInfo {
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uint8_t counts[SHADES];
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uint8_t prescaler[SHADES];
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} timerInfo;
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// Double buffer the timing information, of course.
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timerInfo* frontTimer;
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timerInfo* backTimer;
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timerInfo* tempTimer;
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timerInfo timer[2];
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// Record a slow and fast prescaler for later use
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typedef struct prescalerInfo {
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uint8_t relativeSpeed;
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uint8_t TCCR2;
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} prescalerInfo;
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// TODO: Generate these based on processor type and clock speed
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prescalerInfo slowPrescaler = {1, 0x03};
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//prescalerInfo fastPrescaler = {32, 0x01};
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prescalerInfo fastPrescaler = {4, 0x02};
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static bool initialized = false;
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/// Uncomment to set analog pin 5 high during interrupts, so that an
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/// oscilloscope can be used to measure the processor time taken by it
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//#define MEASURE_ISR_TIME
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//#ifdef MEASURE_ISR_TIME
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//uint8_t statusPIN = 19;
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//#endif
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typedef struct LEDPosition {
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uint8_t high;
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uint8_t low;
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} LEDPosition;
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/* ----------------------------------------------------------------- */
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/** Table for LED Position in leds[] ram table
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*/
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const LEDPosition ledMap[126] = {
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{13, 5}, {13, 6}, {13, 7}, {13, 8}, {13, 9}, {13,10}, {13,11}, {13,12},
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{13, 4}, { 4,13}, {13, 3}, { 3,13}, {13, 2}, { 2,13},
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{12, 5}, {12, 6}, {12, 7}, {12, 8}, {12, 9}, {12,10}, {12,11}, {12,13},
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{12, 4}, { 4,12}, {12, 3}, { 3,12}, {12, 2}, { 2,12},
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{11, 5}, {11, 6}, {11, 7}, {11, 8}, {11, 9}, {11,10}, {11,12}, {11,13},
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{11, 4}, { 4,11}, {11, 3}, { 3,11}, {11, 2}, { 2,11},
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{10, 5}, {10, 6}, {10, 7}, {10, 8}, {10, 9}, {10,11}, {10,12}, {10,13},
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{10, 4}, { 4,10}, {10, 3}, { 3,10}, {10, 2}, { 2,10},
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{ 9, 5}, { 9, 6}, { 9, 7}, { 9, 8}, { 9,10}, { 9,11}, { 9,12}, { 9,13},
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{ 9, 4}, { 4, 9}, { 9, 3}, { 3, 9}, { 9, 2}, { 2, 9},
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{ 8, 5}, { 8, 6}, { 8, 7}, { 8, 9}, { 8,10}, { 8,11}, { 8,12}, { 8,13},
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{ 8, 4}, { 4, 8}, { 8, 3}, { 3, 8}, { 8, 2}, { 2, 8},
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{ 7, 5}, { 7, 6}, { 7, 8}, { 7, 9}, { 7,10}, { 7,11}, { 7,12}, { 7,13},
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{ 7, 4}, { 4, 7}, { 7, 3}, { 3, 7}, { 7, 2}, { 2, 7},
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{ 6, 5}, { 6, 7}, { 6, 8}, { 6, 9}, { 6,10}, { 6,11}, { 6,12}, { 6,13},
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{ 6, 4}, { 4, 6}, { 6, 3}, { 3, 6}, { 6, 2}, { 2, 6},
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{ 5, 6}, { 5, 7}, { 5, 8}, { 5, 9}, { 5,10}, { 5,11}, { 5,12}, { 5,13},
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{ 5, 4}, { 4, 5}, { 5, 3}, { 3, 5}, { 5, 2}, { 2, 5},
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};
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/* ----------------------------------------------------------------- */
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/** Constructor : Initialize the interrupt code.
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* should be called in setup();
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*/
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void LedSignInit(uint8_t mode)
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{
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//#ifdef MEASURE_ISR_TIME
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// pinMode(statusPIN, OUTPUT);
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// digitalWrite(statusPIN, LOW);
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//#endif
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float prescaler = 0.0;
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#if defined (__AVR_ATmega168__) || defined (__AVR_ATmega48__) || defined (__AVR_ATmega88__) || defined (__AVR_ATmega328P__) || (__AVR_ATmega1280__)
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TIMSK2 &= ~(1<<TOIE2);
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TCCR2A &= ~((1<<WGM21) | (1<<WGM20));
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TCCR2B &= ~(1<<WGM22);
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ASSR &= ~(1<<AS2);
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TIMSK2 &= ~(1<<OCIE2A);
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if ((F_CPU >= 1000000UL) && (F_CPU <= 16000000UL)) { // prescaler set to 64
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TCCR2B |= ((1<<CS21) | (1<<CS20));
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TCCR2B &= ~(1<<CS22);
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prescaler = 32.0;
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} else if (F_CPU < 1000000UL) { // prescaler set to 8
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TCCR2B |= (1<<CS21);
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TCCR2B &= ~((1<<CS22) | (1<<CS20));
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prescaler = 8.0;
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} else { // F_CPU > 16Mhz, prescaler set to 128
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TCCR2B |= (1<<CS22);
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TCCR2B &= ~((1<<CS21) | (1<<CS20));
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prescaler = 64.0;
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}
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#elif defined (__AVR_ATmega8__)
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TIMSK &= ~(1<<TOIE2);
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TCCR2 &= ~((1<<WGM21) | (1<<WGM20));
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TIMSK &= ~(1<<OCIE2);
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ASSR &= ~(1<<AS2);
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if ((F_CPU >= 1000000UL) && (F_CPU <= 16000000UL)) { // prescaler set to 64
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TCCR2 |= (1<<CS22);
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TCCR2 &= ~((1<<CS21) | (1<<CS20));
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prescaler = 64.0;
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} else if (F_CPU < 1000000UL) { // prescaler set to 8
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TCCR2 |= (1<<CS21);
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TCCR2 &= ~((1<<CS22) | (1<<CS20));
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prescaler = 8.0;
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} else { // F_CPU > 16Mhz, prescaler set to 128
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TCCR2 |= ((1<<CS22) && (1<<CS20));
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TCCR2 &= ~(1<<CS21);
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prescaler = 128.0;
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}
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#elif defined (__AVR_ATmega128__)
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TIMSK &= ~(1<<TOIE2);
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TCCR2 &= ~((1<<WGM21) | (1<<WGM20));
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TIMSK &= ~(1<<OCIE2);
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if ((F_CPU >= 1000000UL) && (F_CPU <= 16000000UL)) { // prescaler set to 64
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TCCR2 |= ((1<<CS21) | (1<<CS20));
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TCCR2 &= ~(1<<CS22);
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prescaler = 64.0;
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} else if (F_CPU < 1000000UL) { // prescaler set to 8
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TCCR2 |= (1<<CS21);
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TCCR2 &= ~((1<<CS22) | (1<<CS20));
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prescaler = 8.0;
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} else { // F_CPU > 16Mhz, prescaler set to 256
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TCCR2 |= (1<<CS22);
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TCCR2 &= ~((1<<CS21) | (1<<CS20));
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prescaler = 256.0;
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}
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#endif
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LedSign_tcnt2 = 256 - (int)((float)F_CPU * 0.0005 / prescaler);
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// Record whether we are in single or double buffer mode
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displayMode = mode;
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videoFlipPage = false;
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// Point the display buffer to the first physical buffer
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displayBuffer = &leds[0];
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// If we are in single buffered mode, point the work buffer
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// at the same physical buffer as the display buffer. Otherwise,
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// point it at the second physical buffer.
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if( displayMode & DOUBLE_BUFFER ) {
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workBuffer = &leds[1];
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}
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else {
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workBuffer = displayBuffer;
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}
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// Set up the timer buffering
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frontTimer = &timer[0];
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backTimer = &timer[1];
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videoFlipTimer = false;
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LedSignSetBrightness(127);
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// Clear the buffer and display it
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LedSignClear(0);
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LedSignFlip(false);
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// Then start the display
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TCNT2 = LedSign_tcnt2;
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#if defined (__AVR_ATmega168__) || defined (__AVR_ATmega48__) || defined (__AVR_ATmega88__) || defined (__AVR_ATmega328P__) || (__AVR_ATmega1280__)
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TIMSK2 |= (1<<TOIE2);
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#elif defined (__AVR_ATmega128__) || defined (__AVR_ATmega8__)
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TIMSK |= (1<<TOIE2);
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#endif
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// If we are in double-buffer mode, wait until the display flips before we
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// return
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if (displayMode & DOUBLE_BUFFER)
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{
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while (videoFlipPage) {
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_delay_ms(1);
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}
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}
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initialized = true;
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}
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/* ----------------------------------------------------------------- */
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/** Signal that the front and back buffers should be flipped
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* @param blocking if true : wait for flip before returning, if false :
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* return immediately.
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*/
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void LedSignFlip(bool blocking)
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{
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if (displayMode & DOUBLE_BUFFER)
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{
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// Just set the flip flag, the buffer will flip between redraws
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videoFlipPage = true;
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// If we are blocking, sit here until the page flips.
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while (blocking && videoFlipPage) {
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_delay_ms(1);
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}
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}
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}
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/* ----------------------------------------------------------------- */
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/** Clear the screen completely
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* @param set if 1 : make all led ON, if not set or 0 : make all led OFF
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*/
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void LedSignClear(int set) {
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int x, y;
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for(x=0;x<14;x++)
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for(y=0;y<9;y++)
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LedSignSet(x,y,set);
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}
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/* ----------------------------------------------------------------- */
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/** Clear an horizontal line completely
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* @param y is the y coordinate of the line to clear/light [0-8]
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* @param set if 1 : make all led ON, if not set or 0 : make all led OFF
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*/
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void LedSignHorizontal(int y, int set) {
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int x;
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for(x=0;x<14;x++)
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LedSignSet(x,y,set);
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}
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/* ----------------------------------------------------------------- */
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/** Clear a vertical line completely
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* @param x is the x coordinate of the line to clear/light [0-13]
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* @param set if 1 : make all led ON, if not set or 0 : make all led OFF
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*/
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void LedSignVertical(int x, int set) {
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int y;
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for(y=0;y<9;y++)
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LedSignSet(x,y,set);
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}
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/* ----------------------------------------------------------------- */
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/** Set : switch on and off the leds. All the position #for char in frameString:
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* calculations are done here, so we don't need to do in the
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* interrupt code
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*/
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void LedSignSet(uint8_t x, uint8_t y, uint8_t c)
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{
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uint8_t pin_high = ledMap[x+y*14].high;
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uint8_t pin_low = ledMap[x+y*14].low;
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// pin_low is directly the address in the led array (minus 2 because the
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// first two bytes are used for RS232 communication), but
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// as it is a two byte array we need to check pin_high also.
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// If pin_high is bigger than 8 address has to be increased by one
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uint8_t bufferNum = (pin_low-2)*2 + (pin_high / 8) + ((pin_high > 7)?24:0);
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uint8_t work = _BV(pin_high & 0x07);
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// If we aren't in grayscale mode, just map any pin brightness to max
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if (c > 0 && !(displayMode & GRAYSCALE)) {
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c = SHADES-1;
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}
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int i;
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for (i = 0; i < SHADES-1; i++) {
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if( c > i ) {
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workBuffer->pixels[i][bufferNum] |= work; // ON
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}
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else {
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workBuffer->pixels[i][bufferNum] &= ~work; // OFF
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}
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}
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}
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/* Set the overall brightness of the screen
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* @param brightness LED brightness, from 0 (off) to 127 (full on)
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*/
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void LedSignSetBrightness(uint8_t brightness)
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{
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// An exponential fit seems to approximate a (perceived) linear scale
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float brightnessPercent = ((float)brightness / 127)*((float)brightness / 127);
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uint8_t difference = 0;
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/* ---- This needs review! Please review. -- thilo */
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// set up page counts
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// TODO: make SHADES a function parameter. This would require some refactoring.
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int start = 15;
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int max = 255;
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float scale = 1.5;
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float delta = pow( max - start , 1.0 / scale) / (SHADES - 1);
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uint8_t pageCounts[SHADES];
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pageCounts[0] = max - start;
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uint8_t i;
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for (i=1; i<SHADES; i++) {
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pageCounts[i] = max - ( pow( i * delta, scale ) + start );
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}
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//Serial.end();
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if (! initialized) {
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// set front timer defaults
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int i;
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for (i = 0; i < SHADES; i++) {
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frontTimer->counts[i] = pageCounts[i];
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// TODO: Generate this dynamically
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frontTimer->prescaler[i] = slowPrescaler.TCCR2;
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}
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}
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// Wait until the previous brightness request goes through
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while( videoFlipTimer ) {
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_delay_ms(1);
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}
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// Compute on time for each of the pages
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// Use the fast timer; slow timer is only useful for < 3 shades.
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for (i = 0; i < SHADES - 1; i++) {
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uint8_t interval = 255 - pageCounts[i];
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backTimer->counts[i] = 255 - brightnessPercent
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* interval
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* fastPrescaler.relativeSpeed;
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backTimer->prescaler[i] = fastPrescaler.TCCR2;
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difference += backTimer->counts[i] - pageCounts[i];
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}
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// Compute off time
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backTimer->counts[SHADES - 1] = 255 - difference;
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backTimer->prescaler[SHADES - 1] = slowPrescaler.TCCR2;
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/* ---- End of "This needs review! Please review." -- thilo */
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// Have the ISR update the timer registers next run
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videoFlipTimer = true;
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}
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/* ----------------------------------------------------------------- */
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/** The Interrupt code goes here !
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*/
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ISR(TIMER2_OVF_vect) {
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DDRD = 0x0;
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DDRB = 0x0;
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//#ifdef MEASURE_ISR_TIME
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// digitalWrite(statusPIN, HIGH);
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//#endif
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// For each cycle, we have potential SHADES pages to display.
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// Once every page has been displayed, then we move on to the next
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// cycle.
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// 24 Cycles of Matrix
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static uint8_t cycle = 0;
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// SHADES pages to display
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static uint8_t page = 0;
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TCCR2B = frontTimer->prescaler[page];
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TCNT2 = frontTimer->counts[page];
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if ( page < SHADES - 1) {
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if (cycle < 6) {
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DDRD = _BV(cycle+2) | displayBuffer->pixels[page][cycle*2];
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PORTD = displayBuffer->pixels[page][cycle*2];
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DDRB = displayBuffer->pixels[page][cycle*2+1];
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PORTB = displayBuffer->pixels[page][cycle*2+1];
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} else if (cycle < 12) {
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DDRD = displayBuffer->pixels[page][cycle*2];
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PORTD = displayBuffer->pixels[page][cycle*2];
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DDRB = _BV(cycle-6) | displayBuffer->pixels[page][cycle*2+1];
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PORTB = displayBuffer->pixels[page][cycle*2+1];
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} else if (cycle < 18) {
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DDRD = _BV(cycle+2-12) | displayBuffer->pixels[page][cycle*2];
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PORTD = displayBuffer->pixels[page][cycle*2];
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DDRB = displayBuffer->pixels[page][cycle*2+1];
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PORTB = displayBuffer->pixels[page][cycle*2+1];
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} else {
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DDRD = displayBuffer->pixels[page][cycle*2];
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PORTD = displayBuffer->pixels[page][cycle*2];
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DDRB = _BV(cycle-6-12) | displayBuffer->pixels[page][cycle*2+1];
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PORTB = displayBuffer->pixels[page][cycle*2+1];
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}
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}
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else {
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// Turn everything off
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DDRD = 0x0;
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DDRB = 0x0;
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}
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page++;
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if (page >= SHADES) {
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page = 0;
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cycle++;
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}
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if (cycle > 24) {
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cycle = 0;
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// If the page should be flipped, do it here.
|
|
if (videoFlipPage && (displayMode & DOUBLE_BUFFER))
|
|
{
|
|
// TODO: is this an atomic operation?
|
|
videoFlipPage = false;
|
|
|
|
videoPage* temp = displayBuffer;
|
|
displayBuffer = workBuffer;
|
|
workBuffer = temp;
|
|
}
|
|
|
|
if (videoFlipTimer) {
|
|
videoFlipTimer = false;
|
|
|
|
tempTimer = frontTimer;
|
|
frontTimer = backTimer;
|
|
backTimer = tempTimer;
|
|
}
|
|
}
|
|
|
|
//#ifdef MEASURE_ISR_TIME
|
|
// digitalWrite(statusPIN, LOW);
|
|
//#endif
|
|
}
|