mirror of
https://github.com/RIOT-OS/RIOT.git
synced 2024-12-29 04:50:03 +01:00
67 lines
1.7 KiB
C
67 lines
1.7 KiB
C
/*
|
|
* Copyright (C) 2014 Freie Universität Berlin
|
|
*
|
|
* This file is subject to the terms and conditions of the GNU Lesser
|
|
* General Public License v2.1. See the file LICENSE in the top level
|
|
* directory for more details.
|
|
*/
|
|
|
|
/**
|
|
* @ingroup cpu_samd21
|
|
* @{
|
|
*
|
|
* @file
|
|
* @brief Implementation of the CPU initialization
|
|
*
|
|
* @author Thomas Eichinger <thomas.eichinger@fu-berlin.de>
|
|
* @}
|
|
*/
|
|
|
|
#include "cpu.h"
|
|
|
|
void clk_init(void);
|
|
|
|
/**
|
|
* @brief Initialize the CPU, set IRQ priorities
|
|
*/
|
|
void cpu_init(void)
|
|
{
|
|
/* pm clk enable */
|
|
PM->APBAMASK.reg = PM_APBAMASK_PM;
|
|
/* port clk enable */
|
|
PM->APBBMASK.reg |= PM_APBBMASK_PORT;
|
|
/* disable the watchdog timer */
|
|
WDT->CTRL.bit.ENABLE = 0;
|
|
|
|
/* set pendSV interrupt to lowest possible priority */
|
|
NVIC_SetPriority(PendSV_IRQn, 0xff);
|
|
|
|
/* Initialise clock sources and generic clocks */
|
|
clk_init();
|
|
}
|
|
|
|
/**
|
|
* @brief Initialise clock sources and generic clocks
|
|
*/
|
|
void clk_init(void)
|
|
{
|
|
PM->APBAMASK.reg |= PM_APBAMASK_SYSCTRL;
|
|
PM->APBAMASK.reg |= PM_APBAMASK_GCLK;
|
|
|
|
SYSCTRL->OSC8M.bit.PRESC = 0;
|
|
SYSCTRL->OSC8M.bit.ONDEMAND = 1;
|
|
SYSCTRL->OSC8M.bit.RUNSTDBY = 0;
|
|
SYSCTRL->OSC8M.bit.ENABLE = 1;
|
|
|
|
/* Software reset the module to ensure it is re-initialized correctly */
|
|
GCLK->CTRL.reg = GCLK_CTRL_SWRST;
|
|
while (GCLK->CTRL.reg & GCLK_CTRL_SWRST);
|
|
|
|
while (GCLK->STATUS.reg & GCLK_STATUS_SYNCBUSY);
|
|
/* Select the correct generator */
|
|
*((uint8_t*)&GCLK->GENDIV.reg) = 0;
|
|
while (GCLK->STATUS.reg & GCLK_STATUS_SYNCBUSY);
|
|
GCLK->GENCTRL.reg = (GCLK_GENCTRL_GENEN | GCLK_GENCTRL_SRC_OSC8M | GCLK_CLKCTRL_GEN_GCLK0);
|
|
while (GCLK->STATUS.reg & GCLK_STATUS_SYNCBUSY);
|
|
}
|