--- /dev/null
+/*
+ * Copyright © 2023 Keith Packard <keithp@keithp.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#include "ao.h"
+
+void
+ao_clock_init(void)
+{
+ uint32_t cfgr;
+
+ /* Switch to HSI while messing about */
+ stm_rcc.cr |= (1 << STM_RCC_CR_HSION);
+ while (!(stm_rcc.cr & (1 << STM_RCC_CR_HSIRDY)))
+ ao_arch_nop();
+
+ stm_rcc.cfgr = (stm_rcc.cfgr & ~(uint32_t) (STM_RCC_CFGR_SW_MASK << STM_RCC_CFGR_SW)) |
+ (STM_RCC_CFGR_SW_HSI << STM_RCC_CFGR_SW);
+
+ /* wait for system to switch to HSI */
+ while ((stm_rcc.cfgr & (STM_RCC_CFGR_SWS_MASK << STM_RCC_CFGR_SWS)) !=
+ (STM_RCC_CFGR_SWS_HSI << STM_RCC_CFGR_SWS))
+ ao_arch_nop();
+
+ /* Disable all interrupts */
+ stm_rcc.cir = 0;
+
+#if AO_HSE
+#if AO_HSE_BYPASS
+ stm_rcc.cr |= (1 << STM_RCC_CR_HSEBYP);
+#else
+ stm_rcc.cr &= ~(uint32_t) (1 << STM_RCC_CR_HSEBYP);
+#endif
+ /* Enable HSE clock */
+ stm_rcc.cr |= (1 << STM_RCC_CR_HSEON);
+ while (!(stm_rcc.cr & (1 << STM_RCC_CR_HSERDY)))
+ asm("nop");
+
+#define STM_RCC_CFGR_SWS_TARGET_CLOCK (STM_RCC_CFGR_SWS_HSE << STM_RCC_CFGR_SWS)
+#define STM_RCC_CFGR_SW_TARGET_CLOCK (STM_RCC_CFGR_SW_HSE)
+#define STM_PLLSRC AO_HSE
+#define STM_RCC_CFGR_PLLSRC_TARGET_CLOCK (STM_RCC_CFGR_PLLSRC_HSE << STM_RCC_CFGR_PLLSRC)
+#else
+#define STM_HSI 16000000
+#define STM_RCC_CFGR_SWS_TARGET_CLOCK (STM_RCC_CFGR_SWS_HSI << STM_RCC_CFGR_SWS)
+#define STM_RCC_CFGR_SW_TARGET_CLOCK (STM_RCC_CFGR_SW_HSI)
+#define STM_PLLSRC (STM_HSI/2)
+#define STM_RCC_CFGR_PLLSRC_TARGET_CLOCK (STM_RCC_CFGR_PLLSRC_HSI_2 << STM_RCC_CFGR_PLLSRC)
+#endif
+
+#if !AO_HSE || HAS_ADC || HAS_ADC_SINGLE
+ /* Enable HSI RC clock 16MHz */
+ stm_rcc.cr |= (1 << STM_RCC_CR_HSION);
+ while (!(stm_rcc.cr & (1 << STM_RCC_CR_HSIRDY)))
+ asm("nop");
+#endif
+
+#if 0
+ /* Set flash latency to tolerate 32MHz SYSCLK -> 1 wait state */
+
+ /* Enable 64-bit access and prefetch */
+ stm_flash.acr |= (1 << STM_FLASH_ACR_ACC64);
+ stm_flash.acr |= (1 << STM_FLASH_ACR_PRFEN);
+
+ /* Enable 1 wait state so the CPU can run at 32MHz */
+ stm_flash.acr |= (1 << STM_FLASH_ACR_LATENCY);
+#endif
+
+ /* Enable power interface clock */
+ stm_rcc.apb1enr |= (1 << STM_RCC_APB1ENR_PWREN);
+
+#if 0
+ /* Set voltage range to 1.8V */
+
+ /* poll VOSF bit in PWR_CSR. Wait until it is reset to 0 */
+ while ((stm_pwr.csr & (1 << STM_PWR_CSR_VOSF)) != 0)
+ asm("nop");
+
+ /* Configure voltage scaling range */
+ cr = stm_pwr.cr;
+ cr &= ~(STM_PWR_CR_VOS_MASK << STM_PWR_CR_VOS);
+ cr |= (STM_PWR_CR_VOS_1_8 << STM_PWR_CR_VOS);
+ stm_pwr.cr = cr;
+
+ /* poll VOSF bit in PWR_CSR. Wait until it is reset to 0 */
+ while ((stm_pwr.csr & (1 << STM_PWR_CSR_VOSF)) != 0)
+ asm("nop");
+#endif
+
+ /* HCLK */
+ cfgr = stm_rcc.cfgr;
+ cfgr &= ~(STM_RCC_CFGR_HPRE_MASK << STM_RCC_CFGR_HPRE);
+ cfgr |= (AO_RCC_CFGR_HPRE_DIV << STM_RCC_CFGR_HPRE);
+ stm_rcc.cfgr = cfgr;
+ while ((stm_rcc.cfgr & (STM_RCC_CFGR_HPRE_MASK << STM_RCC_CFGR_HPRE)) !=
+ (AO_RCC_CFGR_HPRE_DIV << STM_RCC_CFGR_HPRE))
+ asm ("nop");
+
+ /* APB1 Prescaler = AO_APB1_PRESCALER */
+ cfgr = stm_rcc.cfgr;
+ cfgr &= ~(STM_RCC_CFGR_PPRE1_MASK << STM_RCC_CFGR_PPRE1);
+ cfgr |= (AO_RCC_CFGR_PPRE1_DIV << STM_RCC_CFGR_PPRE1);
+ stm_rcc.cfgr = cfgr;
+
+ /* APB2 Prescaler = AO_APB2_PRESCALER */
+ cfgr = stm_rcc.cfgr;
+ cfgr &= ~(STM_RCC_CFGR_PPRE2_MASK << STM_RCC_CFGR_PPRE2);
+ cfgr |= (AO_RCC_CFGR_PPRE2_DIV << STM_RCC_CFGR_PPRE2);
+ stm_rcc.cfgr = cfgr;
+
+ /* Disable the PLL */
+ stm_rcc.cr &= ~(1UL << STM_RCC_CR_PLLON);
+ while (stm_rcc.cr & (1UL << STM_RCC_CR_PLLRDY))
+ asm("nop");
+
+ /* PLLVCO */
+ cfgr = stm_rcc.cfgr;
+ cfgr &= ~(STM_RCC_CFGR_PLLMUL_MASK << STM_RCC_CFGR_PLLMUL);
+
+ cfgr |= (AO_RCC_CFGR_PLLMUL << STM_RCC_CFGR_PLLMUL);
+
+ /* PLL source */
+ cfgr &= ~(1UL << STM_RCC_CFGR_PLLSRC);
+ cfgr |= STM_RCC_CFGR_PLLSRC_TARGET_CLOCK;
+
+ stm_rcc.cfgr = cfgr;
+
+ /* Enable the PLL and wait for it */
+ stm_rcc.cr |= (1 << STM_RCC_CR_PLLON);
+ while (!(stm_rcc.cr & (1 << STM_RCC_CR_PLLRDY)))
+ asm("nop");
+
+ /* Switch to the PLL for the system clock */
+
+ cfgr = stm_rcc.cfgr;
+ cfgr &= ~(STM_RCC_CFGR_SW_MASK << STM_RCC_CFGR_SW);
+ cfgr |= (STM_RCC_CFGR_SW_PLL << STM_RCC_CFGR_SW);
+ stm_rcc.cfgr = cfgr;
+ for (;;) {
+ uint32_t c, part, mask, val;
+
+ c = stm_rcc.cfgr;
+ mask = (STM_RCC_CFGR_SWS_MASK << STM_RCC_CFGR_SWS);
+ val = (STM_RCC_CFGR_SWS_PLL << STM_RCC_CFGR_SWS);
+ part = c & mask;
+ if (part == val)
+ break;
+ }
+
+#if 0
+ stm_rcc.apb2rstr = 0xffff;
+ stm_rcc.apb1rstr = 0xffff;
+ stm_rcc.ahbrstr = 0x3f;
+ stm_rcc.ahbenr = (1 << STM_RCC_AHBENR_FLITFEN);
+ stm_rcc.apb2enr = 0;
+ stm_rcc.apb1enr = 0;
+ stm_rcc.ahbrstr = 0;
+ stm_rcc.apb1rstr = 0;
+ stm_rcc.apb2rstr = 0;
+#endif
+
+ /* Clear reset flags */
+ stm_rcc.csr |= (1 << STM_RCC_CSR_RMVF);
+
+
+#if DEBUG_THE_CLOCK
+ /* Output SYSCLK on PA8 for measurments */
+
+ stm_rcc.ahbenr |= (1 << STM_RCC_AHBENR_GPIOAEN);
+
+ stm_afr_set(&stm_gpioa, 8, STM_AFR_AF0);
+ stm_moder_set(&stm_gpioa, 8, STM_MODER_ALTERNATE);
+ stm_ospeedr_set(&stm_gpioa, 8, STM_OSPEEDR_40MHz);
+
+ stm_rcc.cfgr |= (STM_RCC_CFGR_MCOPRE_DIV_1 << STM_RCC_CFGR_MCOPRE);
+ stm_rcc.cfgr |= (STM_RCC_CFGR_MCOSEL_HSE << STM_RCC_CFGR_MCOSEL);
+#endif
+}
projects / fw / altos / blobdiff