mirror of
https://github.com/trezor/trezor-firmware.git
synced 2024-12-26 16:18:22 +00:00
60 lines
1.5 KiB
C
60 lines
1.5 KiB
C
/*
|
|
* This file is part of the Trezor project, https://trezor.io/
|
|
*
|
|
* Copyright (C) 2016 Saleem Rashid <trezor@saleemrashid.com>
|
|
*
|
|
* This library is free software: you can redistribute it and/or modify
|
|
* it under the terms of the GNU Lesser General Public License as published by
|
|
* the Free Software Foundation, either version 3 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This library 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 Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public License
|
|
* along with this library. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#include "timer.h"
|
|
|
|
#include <libopencm3/cm3/systick.h>
|
|
#include <libopencm3/cm3/vector.h>
|
|
#include <libopencm3/stm32/rcc.h>
|
|
|
|
/* 1 tick = 1 ms */
|
|
extern volatile uint32_t system_millis;
|
|
|
|
/*
|
|
* Initialise the Cortex-M3 SysTick timer
|
|
*/
|
|
void timer_init(void) {
|
|
system_millis = 0;
|
|
|
|
/*
|
|
* MCU clock (120 MHz) as source
|
|
*
|
|
* (120 MHz / 8) = 15 clock pulses
|
|
*
|
|
*/
|
|
systick_set_clocksource(STK_CSR_CLKSOURCE_AHB_DIV8);
|
|
STK_CVR = 0;
|
|
|
|
/*
|
|
* 1 tick = 1 ms @ 120 MHz
|
|
*
|
|
* (15 clock pulses * 1000 ms) = 15000 clock pulses
|
|
*
|
|
* Send an interrupt every (N - 1) clock pulses
|
|
*/
|
|
systick_set_reload(14999);
|
|
|
|
/* SysTick as interrupt */
|
|
systick_interrupt_enable();
|
|
|
|
systick_counter_enable();
|
|
}
|
|
|
|
void sys_tick_handler(void) { system_millis++; }
|