From 62849f043c9e1d9bf06f964d0be516301dfe82a4 Mon Sep 17 00:00:00 2001 From: Karl Palsson Date: Tue, 12 Jun 2012 15:23:16 +0000 Subject: Add helper function for max clock on HSI for f100 Based on existing HSI code. Tested with f100c8, on custom board with no external crystals or resonators. --- lib/stm32/f1/rcc.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) (limited to 'lib/stm32/f1') diff --git a/lib/stm32/f1/rcc.c b/lib/stm32/f1/rcc.c index 8945e80..d127074 100644 --- a/lib/stm32/f1/rcc.c +++ b/lib/stm32/f1/rcc.c @@ -436,6 +436,53 @@ void rcc_clock_setup_in_hsi_out_48mhz(void) rcc_ppre2_frequency = 48000000; } +void rcc_clock_setup_in_hsi_out_24mhz(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); + + /* + * Set prescalers for AHB, ADC, ABP1, ABP2. + * Do this before touching the PLL (TODO: why?). + */ + rcc_set_hpre(RCC_CFGR_HPRE_SYSCLK_NODIV); /* Set. 24MHz Max. 24MHz */ + rcc_set_adcpre(RCC_CFGR_ADCPRE_PCLK2_DIV2); /* Set. 12MHz Max. 12MHz */ + rcc_set_ppre1(RCC_CFGR_PPRE1_HCLK_NODIV); /* Set. 24MHz Max. 24MHz */ + rcc_set_ppre2(RCC_CFGR_PPRE2_HCLK_NODIV); /* Set. 24MHz Max. 24MHz */ + + /* + * Sysclk is (will be) running with 24MHz -> 2 waitstates. + * 0WS from 0-24MHz + * 1WS from 24-48MHz + * 2WS from 48-72MHz + */ + flash_set_ws(FLASH_LATENCY_0WS); + + /* + * Set the PLL multiplication factor to 6. + * 8MHz (internal) * 6 (multiplier) / 2 (PLLSRC_HSI_CLK_DIV2) = 24MHz + */ + rcc_set_pll_multiplication_factor(RCC_CFGR_PLLMUL_PLL_CLK_MUL6); + + /* Select HSI/2 as PLL source. */ + rcc_set_pll_source(RCC_CFGR_PLLSRC_HSI_CLK_DIV2); + + /* 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); + + /* Set the peripheral clock frequencies used */ + rcc_ppre1_frequency = 24000000; + rcc_ppre2_frequency = 24000000; +} + + void rcc_clock_setup_in_hse_8mhz_out_24mhz(void) { /* Enable internal high-speed oscillator. */ -- cgit v1.2.3