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/*
* This file sets the system clock to its full glory of 80Mhz
*/
#include "clock.h"
#include <stdint.h>
#include "flash.h"
#include "gpio.h"
#include "spin.h"
#define TIMEOUT 10000
int pll_off()
{
uint32_t c;
RCC.c.pllon = false;
for (c = 0; c < TIMEOUT && RCC.c.pllrdy; ++c)
; /* Wait for OFF. */
if (c == TIMEOUT) {
return E_TIMEOUT;
}
return 0;
}
int pll_on()
{
uint32_t c;
RCC.c.pllon = true;
for (c = 0; c < TIMEOUT && !RCC.c.pllrdy; ++c)
; /* Wait for RDY. */
if (c == TIMEOUT) {
return E_TIMEOUT;
}
return 0;
}
int configure_pll(
uint8_t pllp_div_factor, pll_divisor_t pllr, /* System clock divisor. */
pll_divisor_t pllq, /* Divison factor for PLL48M1CLK. */
pllp_divisor_t pllp, /* Divison factor for PLLSAI2CLK. */
uint8_t plln, /* PLL numerator. */
pllm_divisor_t pllm, /* PLL denominator. */
pll_src_t pllsrc /* PLL source */)
{
if (RCC.c.pllrdy) {
/* PLL must be off to configure it. */
return E_NOT_OFF;
}
/* Make sure inputs are valid. */
if (pllp_div_factor == 1 || pllp_div_factor > 31) {
return E_BADPLLP_DIV;
}
if (plln < 8 || plln > 86) {
return E_BADPLLN;
}
union RCC_PLLCFGR tmp;
tmp.pllpdiv = pllp_div_factor;
tmp.pllr = pllr >> 1;
tmp.pllren = pllr & 1;
tmp.pllp = pllp >> 1;
tmp.pllpen = pllp & 1;
tmp.pllq = pllq >> 1;
tmp.pllqen = pllq & 1;
tmp.plln = plln;
tmp.pllm = pllm;
tmp.pllsrc = pllsrc;
RCC.pllcfg = tmp;
return 0;
}
int set_system_clock_MHz(uint8_t mhz)
{
/* Set the source of the system colck to MSI temporarily. */
set_system_clock_src(SYSTEM_CLOCK_SRC_MSI);
if (mhz <= 8 || mhz > 80) {
return E_BAD_ARG;
}
pll_off();
configure_pll(
0,
PLL_DIVISOR_4,
PLL_DIVISOR_4,
PLLP_DIVISOR_7,
mhz,
PLLM_DIVISOR_1,
PLL_SRC_MSI);
pll_on();
/* Configure the flash to have 4 wait states. This is required at
* 80 MHz. */
FLASH.ac_r &= ~0x07;
FLASH.ac_r |= 0x04;
/* Set the source of the system colck to PLL. */
set_system_clock_src(SYSTEM_CLOCK_SRC_PLL);
return 0;
}
int set_system_clock_src(system_clock_src_t src)
{
uint8_t value = RCC.cfg.r & ~0x03;
RCC.cfg.r = value | src;
}
int enable_hsi(__IO rcc_t* rcc, bool enable)
{
uint32_t c;
rcc->c.hsion = !!enable;
for(c = 0; c < TIMEOUT && !rcc->c.hsirdy; ++ c)
;
if (c == TIMEOUT) {
return E_TIMEOUT;
}
return 0;
}
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