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/*
* Aug 2016 Karl Palsson <karlp@tweak.net.au>
*/
#include <libopencm3/stm32/flash.h>
#include <libopencm3/stm32/gpio.h>
#include <libopencm3/stm32/pwr.h>
#include <libopencm3/stm32/rcc.h>
/* Disco board is b6 */
#define LEDPORT GPIOB
#define LEDPIN GPIO6
/**
* blink led count times, with vile hack * 1000 asm nops
*/
static void hack_blink(int count, int hack)
{
for (int i = 0; i < count; i++) {
gpio_toggle(LEDPORT, LEDPIN);
for (int k = 0; k < hack * 1000; k++) {
__asm__("nop");
}
}
}
int main(void)
{
int i;
int j = 0;
/* Allow leds on any port */
RCC_AHBENR |= 0xff;
gpio_mode_setup(LEDPORT, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, LEDPIN);
/* blink twice with slow msi reset clock */
hack_blink(4, 60);
/* step forward to HSI/2, 8Mhz */
struct rcc_clock_scale v2_8low = {
.hpre = RCC_CFGR_HPRE_SYSCLK_DIV2,
.ppre1 = RCC_CFGR_PPRE1_HCLK_NODIV,
.ppre2 = RCC_CFGR_PPRE2_HCLK_NODIV,
.voltage_scale = PWR_SCALE2,
.flash_config = FLASH_ACR_LATENCY_0WS,
.ahb_frequency = 8000000,
.apb1_frequency = 8000000,
.apb2_frequency = 8000000,
};
rcc_clock_setup_hsi(&v2_8low);
/* blink twice again, different rate */
hack_blink(4, 60);
/* step forward to HSI->PLL@32Mhz, range 1 */
rcc_clock_setup_pll(&rcc_clock_config[RCC_CLOCK_VRANGE1_HSI_PLL_32MHZ]);
/* blink twice again */
hack_blink(4, 400);
/* back down again */
rcc_clock_setup_hsi(&v2_8low);
hack_blink(4, 60);
/* just keep blinking */
while (1) {
hack_blink(1, 400);
}
return 0;
}
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