| /*************************************************************************** |
| * __________ __ ___. |
| * Open \______ \ ____ ____ | | _\_ |__ _______ ___ |
| * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / |
| * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < |
| * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ |
| * \/ \/ \/ \/ \/ |
| * $Id$ |
| * |
| * Copyright (C) 2007 by Michael Sevakis |
| * |
| * 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, or (at your option) any later version. |
| * |
| * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY |
| * KIND, either express or implied. |
| * |
| ****************************************************************************/ |
| #include "config.h" |
| #include "system.h" |
| #include "kernel.h" |
| #include "timer.h" |
| #include "thread.h" |
| |
| extern void (*tick_funcs[MAX_NUM_TICK_TASKS])(void); |
| |
| void tick_start(unsigned int interval_in_ms) |
| { |
| /* |
| * Based on default PCLK of 49.1568MHz - scaling chosen to give |
| * remainder-free result for tick interval of 10ms (100Hz) |
| * Timer input clock frequency = |
| * fPCLK / {prescaler value+1} / {divider value} |
| * TIMER_FREQ = 49156800 / 2 |
| * 13300 = TIMER_FREQ / 231 / 8 |
| * 49156800 = 19*(11)*(7)*7*5*5*(3)*2*2*2*2*2*2 |
| * 231 = 11*7*3 |
| */ |
| |
| /* stop timer 4 */ |
| TCON &= ~(1 << 20); |
| /* Set the count for timer 4 */ |
| TCNTB4 = (TIMER_FREQ / 231 / 8) * interval_in_ms / 1000; |
| /* Set the the prescaler value for timers 2,3, and 4 */ |
| TCFG0 = (TCFG0 & ~0xff00) | ((231-1) << 8); |
| /* MUX4 = 1/16 */ |
| TCFG1 = (TCFG1 & ~0xff0000) | 0x030000; |
| /* set manual bit */ |
| TCON |= 1 << 21; |
| /* reset manual bit */ |
| TCON &= ~(1 << 21); |
| /* interval mode */ |
| TCON |= 1 << 22; |
| /* start timer 4 */ |
| TCON |= (1 << 20); |
| |
| /* timer 4 unmask interrupts */ |
| INTMSK &= ~TIMER4_MASK; |
| } |
| |
| void TIMER4(void) |
| { |
| int i; |
| |
| /* Run through the list of tick tasks */ |
| for(i = 0; i < MAX_NUM_TICK_TASKS; i++) |
| { |
| if(tick_funcs[i]) |
| { |
| tick_funcs[i](); |
| } |
| } |
| |
| current_tick++; |
| |
| SRCPND = TIMER4_MASK; |
| INTPND = TIMER4_MASK; |
| } |