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Added 12MHz external clock rcc setup routine.

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This commit is contained in:
Piotr Esden-Tempski 2011-03-09 14:06:58 -08:00
parent ef766da468
commit 7073637430
2 changed files with 55 additions and 1 deletions
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2
examples/stm32/lisa-m/fancyblink/fancyblink.c
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@ -24,7 +24,7 @@
/* Set STM32 to 72 MHz. */
void clock_setup(void)
{
rcc_clock_setup_in_hse_16mhz_out_72mhz();
rcc_clock_setup_in_hse_12mhz_out_72mhz();
/* Enable GPIOC clock. */
rcc_peripheral_enable_clock(&RCC_APB2ENR, RCC_APB2ENR_IOPBEN);

54
lib/stm32/rcc.c
View File

@ -531,6 +531,60 @@ void rcc_clock_setup_in_hse_8mhz_out_72mhz(void)
rcc_set_sysclk_source(RCC_CFGR_SW_SYSCLKSEL_PLLCLK);
}
void rcc_clock_setup_in_hse_12mhz_out_72mhz(void)
{
/* Enable internal high-speed oscillator. */
rcc_osc_on(HSI);
rcc_wait_for_osc_ready(HSI);
/* Select HSI as SYSCLK source. */
rcc_set_sysclk_source(RCC_CFGR_SW_SYSCLKSEL_HSICLK);
/* Enable external high-speed oscillator 16MHz. */
rcc_osc_on(HSE);
rcc_wait_for_osc_ready(HSE);
rcc_set_sysclk_source(RCC_CFGR_SW_SYSCLKSEL_HSECLK);
/*
* Set prescalers for AHB, ADC, ABP1, ABP2.
* Do this before touching the PLL (TODO: why?).
*/
rcc_set_hpre(RCC_CFGR_HPRE_SYSCLK_NODIV); /* Max. 72MHz */
rcc_set_adcpre(RCC_CFGR_ADCPRE_PCLK2_DIV6); /* Max. 14MHz */
rcc_set_ppre1(RCC_CFGR_PPRE1_HCLK_DIV2); /* Max. 36MHz */
rcc_set_ppre2(RCC_CFGR_PPRE2_HCLK_NODIV); /* Max. 72MHz */
/*
* Sysclk runs with 72MHz -> 2 waitstates.
* 0WS from 0-24MHz
* 1WS from 24-48MHz
* 2WS from 48-72MHz
*/
flash_set_ws(FLASH_LATENCY_2WS);
/*
* Set the PLL multiplication factor to 9.
* 12MHz (external) * 6 (multiplier) / 1 (PLLXTPRE_HSE_CLK) = 72MHz
*/
rcc_set_pll_multiplication_factor(RCC_CFGR_PLLMUL_PLL_CLK_MUL6);
/* Select HSI as PLL source. */
rcc_set_pll_source(RCC_CFGR_PLLSRC_HSE_CLK);
/*
* Divide external frequency by 2 before entering PLL
* (only valid/needed for HSE).
*/
rcc_set_pllxtpre(RCC_CFGR_PLLXTPRE_HSE_CLK);
/* Enable PLL oscillator and wait for it to stabilize. */
rcc_osc_on(PLL);
rcc_wait_for_osc_ready(PLL);
/* Select PLL as SYSCLK source. */
rcc_set_sysclk_source(RCC_CFGR_SW_SYSCLKSEL_PLLCLK);
}
void rcc_clock_setup_in_hse_16mhz_out_72mhz(void)
{
/* Enable internal high-speed oscillator. */