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/*
* This file is part of the libopencm3 project.
*
* Copyright (C) 2013 Gareth McMullin <gareth@blacksphere.co.nz>
*
* 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 <libopencm3/sam/pmc.h>
#include <libopencm3/sam/eefc.h>
/** Default peripheral clock frequency after reset. */
uint32_t pmc_mck_frequency = 4000000;
void pmc_xtal_enable(bool en, uint8_t startup_time)
{
if (en) {
CKGR_MOR = (CKGR_MOR & ~CKGR_MOR_MOSCXTST_MASK) |
CKGR_MOR_KEY | CKGR_MOR_MOSCXTEN |
(startup_time << 8);
while (!(PMC_SR & PMC_SR_MOSCXTS));
} else {
CKGR_MOR = CKGR_MOR_KEY | (CKGR_MOR & ~CKGR_MOR_MOSCXTEN);
}
}
void pmc_plla_config(uint8_t mul, uint8_t div)
{
CKGR_PLLAR = CKGR_PLLAR_ONE | ((mul - 1) << 16) |
CKGR_PLLAR_PLLACOUNT_MASK | div;
while (!(PMC_SR & PMC_SR_LOCKA));
}
void pmc_peripheral_clock_enable(uint8_t pid)
{
if (pid < 32) {
PMC_PCER0 = 1 << pid;
} else {
PMC_PCER1 = 1 << (pid & 31);
}
}
void pmc_peripheral_clock_disable(uint8_t pid)
{
if (pid < 32) {
PMC_PCDR0 = 1 << pid;
} else {
PMC_PCDR1 = 1 << (pid & 31);
}
}
void pmc_mck_set_source(enum mck_src src)
{
PMC_MCKR = (PMC_MCKR & ~PMC_MCKR_CSS_MASK) | src;
while (!(PMC_SR & PMC_SR_MCKRDY));
}
void pmc_clock_setup_in_xtal_12mhz_out_84mhz(void)
{
eefc_set_latency(4);
/* 12MHz external xtal, maximum possible startup time */
pmc_xtal_enable(true, 0xff);
/* Select as main oscillator */
CKGR_MOR |= CKGR_MOR_KEY | CKGR_MOR_MOSCSEL;
/* Multiply by 7 for 84MHz */
pmc_plla_config(7, 1);
pmc_mck_set_source(MCK_SRC_PLLA);
pmc_mck_frequency = 84000000;
}
void pmc_clock_setup_in_rc_4mhz_out_84mhz(void)
{
eefc_set_latency(4);
/* Select as main oscillator */
CKGR_MOR = CKGR_MOR_KEY |
(CKGR_MOR & ~(CKGR_MOR_MOSCSEL | CKGR_MOR_MOSCRCF_MASK));
/* Multiply by 21 for 84MHz */
pmc_plla_config(21, 1);
pmc_mck_set_source(MCK_SRC_PLLA);
pmc_mck_frequency = 84000000;
}
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