| 0,0 → 1,68 |
|---|
| /**************************************************************************** |
| * Copyright (C) 2009 by Claas Anders "CaScAdE" Rathje * |
| * admiralcascade@gmail.com * |
| * Project-URL: http://www.mylifesucks.de/oss/c-osd/ * |
| * * |
| * This program is free software; you can redistribute it and/or modify * |
| * it under the terms of the GNU General Public License as published by * |
| * the Free Software Foundation; either version 2 of the License. * |
| * * |
| * This program is distributed in the hope that it will be useful, * |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of * |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * |
| * GNU General Public License for more details. * |
| * * |
| * You should have received a copy of the GNU General Public License * |
| * along with this program; if not, write to the * |
| * Free Software Foundation, Inc., * |
| * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. * |
| ****************************************************************************/ |
| |
| #include <avr/io.h> |
| #include <avr/interrupt.h> |
| #include "ppm.h" |
| #include "main.h" |
| #include "max7456_software_spi.h" // clearing |
| |
| volatile uint16_t old_timer1 = 0, ppm = 0; |
| |
| /** |
| * init ppm, including timer1 for measurement |
| */ |
| void ppm_init() { |
| PORTE |= (1 << PORTE0); // enable pullup on INT0 pin |
| GICR |= (1<<INT2); // External Interrupt Request 2 Enable |
| EMCUCR |= (1<<ISC2); // a rising edge on INT2 activates the interrupt |
| TCCR1B |= (0<<CS12)|(1<<CS10)|(1<<CS11); // timer1 up with prescaler 64 |
| } |
| |
| /** |
| * Handle INT2 interrupts that occur on changing edges of ppm signal |
| */ |
| ISR(INT2_vect) { |
| // since the pin might get bogus reads we wait for 123 signals |
| static uint8_t valid_ppm_to_go = 123; |
| if (EMCUCR & (1<<ISC2)) { // rising |
| old_timer1 = TCNT1; |
| EMCUCR &= ~(1<<ISC2); // next one is falling |
| } else { |
| if (valid_ppm_to_go) { |
| valid_ppm_to_go--; |
| } else { |
| ppm = TCNT1 - old_timer1; |
| ppm -= 256; |
| if (ppm < 128) { // we want HUD |
| COSD_FLAGS |= COSD_FLAG_HUD; |
| } else { // we do not want hud |
| if (COSD_FLAGS & COSD_FLAG_HUD) { |
| clear(); |
| } |
| COSD_FLAGS &= ~COSD_FLAG_HUD; |
| } |
| } |
| EMCUCR |= (1<<ISC2); // next one is rising |
| } |
| //write_ndigit_number_u(2, 2, ppm, 1000, 0); // debug |
| //write_ndigit_number_u(2, 3, valid_ppm_to_go, 100, 0); // debug |
| //write_ndigit_number_u(2, 4, COSD_FLAGS, 100, 0); // debug |
| } |