stm32: Allow external crystal speed to be customized in Kconfig
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
This commit is contained in:
@@ -4,7 +4,7 @@
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//
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// This file may be distributed under the terms of the GNU GPLv3 license.
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#include "autoconf.h" // CONFIG_CLOCK_REF_8M
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#include "autoconf.h" // CONFIG_CLOCK_REF_FREQ
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#include "board/armcm_boot.h" // VectorTable
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#include "board/irq.h" // irq_disable
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#include "board/usb_cdc.h" // usb_request_bootloader
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@@ -129,19 +129,19 @@ clock_setup(void)
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{
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// Configure and enable PLL
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uint32_t cfgr;
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if (CONFIG_CLOCK_REF_8M) {
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// Configure 72Mhz PLL from external 8Mhz crystal (HSE)
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if (!CONFIG_STM32_CLOCK_REF_INTERNAL) {
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// Configure 72Mhz PLL from external crystal (HSE)
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uint32_t div = CONFIG_CLOCK_FREQ / CONFIG_CLOCK_REF_FREQ;
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RCC->CR |= RCC_CR_HSEON;
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cfgr = ((1 << RCC_CFGR_PLLSRC_Pos) | ((9 - 2) << RCC_CFGR_PLLMULL_Pos)
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| RCC_CFGR_PPRE1_DIV2 | RCC_CFGR_PPRE2_DIV2
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| RCC_CFGR_ADCPRE_DIV4);
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cfgr = (1 << RCC_CFGR_PLLSRC_Pos) | ((div - 2) << RCC_CFGR_PLLMULL_Pos);
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} else {
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// Configure 72Mhz PLL from internal 8Mhz oscillator (HSI)
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cfgr = ((0 << RCC_CFGR_PLLSRC_Pos) | ((18 - 2) << RCC_CFGR_PLLMULL_Pos)
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| RCC_CFGR_PPRE1_DIV2 | RCC_CFGR_PPRE2_DIV2
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| RCC_CFGR_ADCPRE_DIV4);
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uint32_t div2 = (CONFIG_CLOCK_FREQ / 8000000) * 2;
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cfgr = ((0 << RCC_CFGR_PLLSRC_Pos)
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| ((div2 - 2) << RCC_CFGR_PLLMULL_Pos));
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}
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RCC->CFGR = cfgr;
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RCC->CFGR = (cfgr | RCC_CFGR_PPRE1_DIV2 | RCC_CFGR_PPRE2_DIV2
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| RCC_CFGR_ADCPRE_DIV4);
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RCC->CR |= RCC_CR_PLLON;
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// Set flash latency
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