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/*
* Copyright © 2016 Keith Packard <keithp@keithp.com>
*
* 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 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 <ao.h>
#include <ao_fast_timer.h>
static void (*ao_fast_timer_callback[AO_FAST_TIMER_MAX])(void);
static uint8_t ao_fast_timer_count;
static uint8_t ao_fast_timer_users;
static void
ao_fast_timer_enable(void)
{
lpc_ct16b0.tcr = ((1 << LPC_CT16B_TCR_CEN) |
(1 << LPC_CT16B_TCR_CRST));
}
static void
ao_fast_timer_disable(void)
{
lpc_ct16b0.tcr = ((0 << LPC_CT16B_TCR_CEN) |
(0 << LPC_CT16B_TCR_CRST));
}
void
ao_fast_timer_on(void (*callback)(void))
{
ao_fast_timer_callback[ao_fast_timer_count] = callback;
if (!ao_fast_timer_count++)
ao_fast_timer_enable();
}
void
ao_fast_timer_off(void (*callback)(void))
{
uint8_t n;
for (n = 0; n < ao_fast_timer_count; n++)
if (ao_fast_timer_callback[n] == callback) {
for (; n < ao_fast_timer_count-1; n++) {
ao_fast_timer_callback[n] = ao_fast_timer_callback[n+1];
}
if (!--ao_fast_timer_count)
ao_fast_timer_disable();
break;
}
}
void lpc_ct16b0_isr(void)
{
uint32_t v = lpc_ct16b0.ir;
int i;
lpc_ct16b0.ir = v;
if (v & (1 << LPC_CT16B_IR_MR0INT)) {
for (i = 0; i < ao_fast_timer_count; i++)
(*ao_fast_timer_callback[i])();
}
}
#ifndef FAST_TIMER_FREQ
#define FAST_TIMER_FREQ 10000
#endif
#define TIMER_FAST (AO_LPC_SYSCLK / FAST_TIMER_FREQ)
void
ao_fast_timer_init(void)
{
if (!ao_fast_timer_users) {
lpc_nvic_set_enable(LPC_ISR_CT16B0_POS);
lpc_nvic_set_priority(LPC_ISR_CT16B0_POS, AO_LPC_NVIC_CLOCK_PRIORITY);
/* Turn on 16-bit timer CT16B0 */
lpc_scb.sysahbclkctrl |= 1 << LPC_SCB_SYSAHBCLKCTRL_CT16B0;
/* Disable timer */
lpc_ct16b0.tcr = 0;
/* scale factor 1 */
lpc_ct16b0.pr = 0;
lpc_ct16b0.pc = 0;
lpc_ct16b0.mcr = ((1 << LPC_CT16B_MCR_MR0I) |
(1 << LPC_CT16B_MCR_MR0R));
lpc_ct16b0.mr[0] = TIMER_FAST;
ao_fast_timer_disable();
}
if (ao_fast_timer_users == AO_FAST_TIMER_MAX)
ao_panic(AO_PANIC_FAST_TIMER);
ao_fast_timer_users++;
}
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