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 |
} |