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| Rev | Author | Line No. | Line |
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| 477 | cascade | 1 | /**************************************************************************** |
| 2 | * Copyright (C) 2009 by Claas Anders "CaScAdE" Rathje * |
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| 3 | * admiralcascade@gmail.com * |
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| 4 | * Project-URL: http://www.mylifesucks.de/oss/c-osd/ * |
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| 5 | * * |
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| 6 | * This program is free software; you can redistribute it and/or modify * |
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| 7 | * it under the terms of the GNU General Public License as published by * |
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| 8 | * the Free Software Foundation; either version 2 of the License. * |
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| 9 | * * |
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| 10 | * This program is distributed in the hope that it will be useful, * |
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| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of * |
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| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * |
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| 13 | * GNU General Public License for more details. * |
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| 14 | * * |
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| 15 | * You should have received a copy of the GNU General Public License * |
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| 16 | * along with this program; if not, write to the * |
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| 17 | * Free Software Foundation, Inc., * |
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| 18 | * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. * |
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| 19 | ****************************************************************************/ |
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| 20 | |||
| 21 | #include <avr/io.h> |
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| 22 | #include <avr/interrupt.h> |
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| 23 | #include "ppm.h" |
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| 24 | #include "main.h" |
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| 25 | #include "max7456_software_spi.h" // clearing |
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| 26 | |||
| 27 | volatile uint16_t old_timer1 = 0, ppm = 0; |
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| 28 | |||
| 29 | /** |
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| 30 | * init ppm, including timer1 for measurement |
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| 31 | */ |
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| 32 | void ppm_init() { |
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| 33 | PORTE |= (1 << PORTE0); // enable pullup on INT0 pin |
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| 34 | GICR |= (1<<INT2); // External Interrupt Request 2 Enable |
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| 35 | EMCUCR |= (1<<ISC2); // a rising edge on INT2 activates the interrupt |
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| 36 | TCCR1B |= (0<<CS12)|(1<<CS10)|(1<<CS11); // timer1 up with prescaler 64 |
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| 37 | } |
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| 38 | |||
| 39 | /** |
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| 40 | * Handle INT2 interrupts that occur on changing edges of ppm signal |
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| 41 | */ |
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| 42 | ISR(INT2_vect) { |
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| 43 | // since the pin might get bogus reads we wait for 123 signals |
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| 44 | static uint8_t valid_ppm_to_go = 123; |
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| 45 | if (EMCUCR & (1<<ISC2)) { // rising |
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| 46 | old_timer1 = TCNT1; |
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| 47 | EMCUCR &= ~(1<<ISC2); // next one is falling |
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| 48 | } else { |
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| 49 | if (valid_ppm_to_go) { |
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| 50 | valid_ppm_to_go--; |
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| 51 | } else { |
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| 52 | ppm = TCNT1 - old_timer1; |
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| 53 | ppm -= 256; |
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| 54 | if (ppm < 128) { // we want HUD |
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| 55 | COSD_FLAGS |= COSD_FLAG_HUD; |
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| 56 | } else { // we do not want hud |
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| 57 | if (COSD_FLAGS & COSD_FLAG_HUD) { |
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| 58 | clear(); |
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| 59 | } |
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| 60 | COSD_FLAGS &= ~COSD_FLAG_HUD; |
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| 61 | } |
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| 62 | } |
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| 63 | EMCUCR |= (1<<ISC2); // next one is rising |
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| 64 | } |
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| 65 | //write_ndigit_number_u(2, 2, ppm, 1000, 0); // debug |
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| 66 | //write_ndigit_number_u(2, 3, valid_ppm_to_go, 100, 0); // debug |
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| 67 | //write_ndigit_number_u(2, 4, COSD_FLAGS, 100, 0); // debug |
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| 68 | } |