| | 1 | /* |
| | 2 | * unzap firmware |
| | 3 | * |
| | 4 | * (c) by Alexander Neumann <alexander@lochraster.org> |
| | 5 | * |
| | 6 | * This program is free software; you can redistribute it and/or modify |
| | 7 | * it under the terms of the GNU General Public License version 2 as |
| | 8 | * published by the Free Software Foundation. |
| | 9 | * |
| | 10 | * This program is distributed in the hope that it will be useful, |
| | 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| | 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| | 13 | * GNU General Public License for more details. |
| | 14 | * |
| | 15 | * You should have received a copy of the GNU General Public License |
| | 16 | * along with this program; if not, write to the Free Software |
| | 17 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| | 18 | * |
| | 19 | * For more information on the GPL, please go to: |
| | 20 | * http://www.gnu.org/copyleft/gpl.html |
| | 21 | */ |
| | 22 | |
| | 23 | #include <stdint.h> |
| | 24 | #include <avr/interrupt.h> |
| | 25 | #include "../common/io.h" |
| | 26 | #include "timer.h" |
| | 27 | |
| | 28 | static volatile uint8_t internal_counter; |
| | 29 | |
| | 30 | void timer_init(void) |
| | 31 | { |
| | 32 | #if defined(__AVR_ATmega8__) |
| | 33 | /* initialize timer2, CTC at 10ms, prescaler 1024 */ |
| | 34 | OCR2 = F_CPU/1024/100; |
| | 35 | TCCR2 = _BV(WGM21) | _BV(CS22) | _BV(CS21) | _BV(CS20); |
| | 36 | TIMSK |= _BV(OCIE2); |
| | 37 | #elif defined(__AVR_ATmega48__) || defined(__AVR_ATmega88__) || defined(__AVR_ATmega168__) |
| | 38 | /* initialize timer2, CTC at 10ms, prescaler 1024 */ |
| | 39 | OCR2A = F_CPU/1024/100; |
| | 40 | TCCR2A = _BV(WGM21); |
| | 41 | TCCR2B = _BV(CS22) | _BV(CS21) | _BV(CS20); |
| | 42 | TIMSK2 = _BV(OCIE2A); |
| | 43 | #else |
| | 44 | #error "unknown controller, unable to initialize timer2" |
| | 45 | #endif |
| | 46 | } |
| | 47 | |
| | 48 | void timer_set(timer_t *t, uint8_t timeout) |
| | 49 | { |
| | 50 | t->current = internal_counter; |
| | 51 | t->timeout = timeout; |
| | 52 | } |
| | 53 | |
| | 54 | bool timer_expired(timer_t *t) |
| | 55 | { |
| | 56 | if (t->timeout == 0) |
| | 57 | return true; |
| | 58 | |
| | 59 | /* attention: this is not correct, if internal_counter is incremented by more than one |
| | 60 | * between two calls of timer_expired()! */ |
| | 61 | if (t->current != internal_counter) { |
| | 62 | t->timeout--; |
| | 63 | t->current = internal_counter; |
| | 64 | } |
| | 65 | |
| | 66 | return false; |
| | 67 | } |
| | 68 | |
| | 69 | /* timer interrupt function */ |
| | 70 | #if defined(__AVR_ATmega8__) |
| | 71 | ISR(TIMER2_COMP_vect, ISR_NOBLOCK) { |
| | 72 | internal_counter++; |
| | 73 | } |
| | 74 | #elif defined(__AVR_ATmega48__) || defined(__AVR_ATmega88__) || defined(__AVR_ATmega168__) |
| | 75 | ISR(TIMER2_COMPA_vect, ISR_NOBLOCK) { |
| | 76 | internal_counter++; |
| | 77 | } |
| | 78 | #endif |
projects / fnordlicht-mini / blame_incremental