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/* *****************************************************************************
* The MIT License
*
* Copyright (c) 2010 Perry Hung.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
* ****************************************************************************/
/**
* @file rcc.c
*
* @brief Implements pretty much only the basic clock setup on the maple,
* exposes a handful of clock enable/disable and peripheral reset commands.
*/
#include "libmaple.h"
#include "flash.h"
#include "rcc.h"
static void set_ahb_prescaler(uint32 divider) {
uint32 cfgr = __read(RCC_CFGR);
cfgr &= ~HPRE;
switch (divider) {
case SYSCLK_DIV_1:
cfgr |= SYSCLK_DIV_1;
break;
default:
ASSERT(0);
}
__write(RCC_CFGR, cfgr);
}
static void set_apb1_prescaler(uint32 divider) {
uint32 cfgr = __read(RCC_CFGR);
cfgr &= ~PPRE1;
switch (divider) {
case HCLK_DIV_2:
cfgr |= HCLK_DIV_2;
break;
default:
ASSERT(0);
}
__write(RCC_CFGR, cfgr);
}
static void set_apb2_prescaler(uint32 divider) {
uint32 cfgr = __read(RCC_CFGR);
cfgr &= ~PPRE2;
switch (divider) {
case HCLK_DIV_1:
cfgr |= HCLK_DIV_1;
break;
default:
ASSERT(0);
}
__write(RCC_CFGR, cfgr);
}
/* FIXME: magic numbers */
static void pll_init(void) {
uint32 cfgr;
cfgr = __read(RCC_CFGR);
cfgr &= (~PLLMUL | PLL_INPUT_CLK_HSE);
/* pll multiplier 9, input clock hse */
__write(RCC_CFGR, cfgr | PLL_MUL_9 | PLL_INPUT_CLK_HSE);
/* enable pll */
__set_bits(RCC_CR, PLLON);
while(!__get_bits(RCC_CR, PLLRDY)) {
asm volatile("nop");
}
/* select pll for system clock source */
cfgr = __read(RCC_CFGR);
cfgr &= ~RCC_CFGR_SWS;
__write(RCC_CFGR, cfgr | RCC_CFGR_SWS_PLL);
while (__get_bits(RCC_CFGR, 0x00000008) != 0x8) {
asm volatile("nop");
}
}
static void hse_init(void) {
__set_bits(RCC_CR, HSEON);
while (!HSERDY) {
asm volatile("nop");
}
}
void rcc_init(void) {
hse_init();
/* Leave this here for now... */
/* Enable Prefetch Buffer */
flash_enable_prefetch();
/* Flash 2 wait state */
flash_set_latency();
set_ahb_prescaler(SYSCLK_DIV_1);
set_apb1_prescaler(HCLK_DIV_2);
set_apb2_prescaler(HCLK_DIV_1);
pll_init();
}
void rcc_set_adc_prescaler(uint32 divider) {
uint32 cfgr = __read(RCC_CFGR);
cfgr &= ~ADCPRE;
__write(RCC_CFGR, cfgr | PCLK2_DIV_2);
}
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