From 927ea196bb8f4b102deadaf2f464febb6e165407 Mon Sep 17 00:00:00 2001
From: gnssuser <gnssuser@github.com>
Date: Mon, 10 Nov 2025 14:11:10 +0100
Subject: [PATCH] CPU clock: 84Mhz reduced to 32MHz

* Clk source: HSE 8MHz crystal osc.
---
 .cproject       |  4 ++--
 Core/Src/main.c | 17 ++++++++---------
 GNSS_Nucleo.ioc | 44 ++++++++++++++++++++++----------------------
 3 files changed, 32 insertions(+), 33 deletions(-)

diff --git a/.cproject b/.cproject
index 138d6e8..b3d641a 100644
--- a/.cproject
+++ b/.cproject
@@ -24,7 +24,7 @@
 							<option id="com.st.stm32cube.ide.mcu.gnu.managedbuild.option.floatabi.108480266" name="Floating-point ABI" superClass="com.st.stm32cube.ide.mcu.gnu.managedbuild.option.floatabi" useByScannerDiscovery="true" value="com.st.stm32cube.ide.mcu.gnu.managedbuild.option.floatabi.value.hard" valueType="enumerated"/>
 							<option id="com.st.stm32cube.ide.mcu.gnu.managedbuild.option.target_board.1440555153" name="Board" superClass="com.st.stm32cube.ide.mcu.gnu.managedbuild.option.target_board" useByScannerDiscovery="false" value="NUCLEO-F401RE" valueType="string"/>
 							<option id="com.st.stm32cube.ide.mcu.gnu.managedbuild.option.defaults.735933396" name="Defaults" superClass="com.st.stm32cube.ide.mcu.gnu.managedbuild.option.defaults" useByScannerDiscovery="false" value="com.st.stm32cube.ide.common.services.build.inputs.revA.1.0.6 || Debug || true || Executable || com.st.stm32cube.ide.mcu.gnu.managedbuild.option.toolchain.value.workspace || NUCLEO-F401RE || 0 || 0 || arm-none-eabi- || ${gnu_tools_for_stm32_compiler_path} || ../Core/Inc | ../Drivers/STM32F4xx_HAL_Driver/Inc | ../Drivers/STM32F4xx_HAL_Driver/Inc/Legacy | ../Drivers/CMSIS/Device/ST/STM32F4xx/Include | ../Drivers/CMSIS/Include ||  ||  || USE_HAL_DRIVER | STM32F401xE ||  || Drivers | Core/Startup | Core ||  ||  || ${workspace_loc:/${ProjName}/STM32F401RETX_FLASH.ld} || true || NonSecure ||  || secure_nsclib.o ||  || None ||  ||  || " valueType="string"/>
-							<option id="com.st.stm32cube.ide.mcu.debug.option.cpuclock.272603146" name="Cpu clock frequence" superClass="com.st.stm32cube.ide.mcu.debug.option.cpuclock" useByScannerDiscovery="false" value="84" valueType="string"/>
+							<option id="com.st.stm32cube.ide.mcu.debug.option.cpuclock.272603146" name="Cpu clock frequence" superClass="com.st.stm32cube.ide.mcu.debug.option.cpuclock" useByScannerDiscovery="false" value="32" valueType="string"/>
 							<targetPlatform archList="all" binaryParser="org.eclipse.cdt.core.ELF" id="com.st.stm32cube.ide.mcu.gnu.managedbuild.targetplatform.1199056163" isAbstract="false" osList="all" superClass="com.st.stm32cube.ide.mcu.gnu.managedbuild.targetplatform"/>
 							<builder buildPath="${workspace_loc:/GNSS_Nucleo}/Debug" id="com.st.stm32cube.ide.mcu.gnu.managedbuild.builder.68958637" keepEnvironmentInBuildfile="false" managedBuildOn="true" name="Gnu Make Builder" parallelBuildOn="true" parallelizationNumber="optimal" superClass="com.st.stm32cube.ide.mcu.gnu.managedbuild.builder"/>
 							<tool id="com.st.stm32cube.ide.mcu.gnu.managedbuild.tool.assembler.1554129155" name="MCU/MPU GCC Assembler" superClass="com.st.stm32cube.ide.mcu.gnu.managedbuild.tool.assembler">
@@ -105,7 +105,7 @@
 							<option id="com.st.stm32cube.ide.mcu.gnu.managedbuild.option.floatabi.1740605827" name="Floating-point ABI" superClass="com.st.stm32cube.ide.mcu.gnu.managedbuild.option.floatabi" useByScannerDiscovery="true" value="com.st.stm32cube.ide.mcu.gnu.managedbuild.option.floatabi.value.hard" valueType="enumerated"/>
 							<option id="com.st.stm32cube.ide.mcu.gnu.managedbuild.option.target_board.812753682" name="Board" superClass="com.st.stm32cube.ide.mcu.gnu.managedbuild.option.target_board" useByScannerDiscovery="false" value="NUCLEO-F401RE" valueType="string"/>
 							<option id="com.st.stm32cube.ide.mcu.gnu.managedbuild.option.defaults.519568019" name="Defaults" superClass="com.st.stm32cube.ide.mcu.gnu.managedbuild.option.defaults" useByScannerDiscovery="false" value="com.st.stm32cube.ide.common.services.build.inputs.revA.1.0.6 || Release || false || Executable || com.st.stm32cube.ide.mcu.gnu.managedbuild.option.toolchain.value.workspace || NUCLEO-F401RE || 0 || 0 || arm-none-eabi- || ${gnu_tools_for_stm32_compiler_path} || ../Core/Inc | ../Drivers/STM32F4xx_HAL_Driver/Inc | ../Drivers/STM32F4xx_HAL_Driver/Inc/Legacy | ../Drivers/CMSIS/Device/ST/STM32F4xx/Include | ../Drivers/CMSIS/Include ||  ||  || USE_HAL_DRIVER | STM32F401xE ||  || Drivers | Core/Startup | Core ||  ||  || ${workspace_loc:/${ProjName}/STM32F401RETX_FLASH.ld} || true || NonSecure ||  || secure_nsclib.o ||  || None ||  ||  || " valueType="string"/>
-							<option id="com.st.stm32cube.ide.mcu.debug.option.cpuclock.992879542" name="Cpu clock frequence" superClass="com.st.stm32cube.ide.mcu.debug.option.cpuclock" useByScannerDiscovery="false" value="84" valueType="string"/>
+							<option id="com.st.stm32cube.ide.mcu.debug.option.cpuclock.992879542" name="Cpu clock frequence" superClass="com.st.stm32cube.ide.mcu.debug.option.cpuclock" useByScannerDiscovery="false" value="32" valueType="string"/>
 							<targetPlatform archList="all" binaryParser="org.eclipse.cdt.core.ELF" id="com.st.stm32cube.ide.mcu.gnu.managedbuild.targetplatform.684191003" isAbstract="false" osList="all" superClass="com.st.stm32cube.ide.mcu.gnu.managedbuild.targetplatform"/>
 							<builder buildPath="${workspace_loc:/GNSS_Nucleo}/Release" id="com.st.stm32cube.ide.mcu.gnu.managedbuild.builder.1367961223" keepEnvironmentInBuildfile="false" managedBuildOn="true" name="Gnu Make Builder" parallelBuildOn="true" parallelizationNumber="optimal" superClass="com.st.stm32cube.ide.mcu.gnu.managedbuild.builder"/>
 							<tool id="com.st.stm32cube.ide.mcu.gnu.managedbuild.tool.assembler.2089101508" name="MCU/MPU GCC Assembler" superClass="com.st.stm32cube.ide.mcu.gnu.managedbuild.tool.assembler">
diff --git a/Core/Src/main.c b/Core/Src/main.c
index 80b4d92..d604566 100644
--- a/Core/Src/main.c
+++ b/Core/Src/main.c
@@ -153,14 +153,13 @@ void SystemClock_Config(void) {
    /** Initializes the RCC Oscillators according to the specified parameters
     * in the RCC_OscInitTypeDef structure.
     */
-   RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
-   RCC_OscInitStruct.HSIState = RCC_HSI_ON;
-   RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
+   RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
+   RCC_OscInitStruct.HSEState = RCC_HSE_ON;
    RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
-   RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI;
-   RCC_OscInitStruct.PLL.PLLM = 16;
-   RCC_OscInitStruct.PLL.PLLN = 336;
-   RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV4;
+   RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
+   RCC_OscInitStruct.PLL.PLLM = 8;
+   RCC_OscInitStruct.PLL.PLLN = 256;
+   RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV8;
    RCC_OscInitStruct.PLL.PLLQ = 7;
    if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK) {
       Error_Handler();
@@ -172,10 +171,10 @@ void SystemClock_Config(void) {
          | RCC_CLOCKTYPE_PCLK1 | RCC_CLOCKTYPE_PCLK2;
    RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
    RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
-   RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;
+   RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
    RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
 
-   if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK) {
+   if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_1) != HAL_OK) {
       Error_Handler();
    }
 }
diff --git a/GNSS_Nucleo.ioc b/GNSS_Nucleo.ioc
index 1fa1ade..6616e65 100644
--- a/GNSS_Nucleo.ioc
+++ b/GNSS_Nucleo.ioc
@@ -114,10 +114,8 @@ PC13-ANTI_TAMP.GPIO_PuPd=GPIO_NOPULL
 PC13-ANTI_TAMP.Locked=true
 PC13-ANTI_TAMP.Signal=GPXTI13
 PC14-OSC32_IN.Locked=true
-PC14-OSC32_IN.Mode=LSE-External-Oscillator
 PC14-OSC32_IN.Signal=RCC_OSC32_IN
 PC15-OSC32_OUT.Locked=true
-PC15-OSC32_OUT.Mode=LSE-External-Oscillator
 PC15-OSC32_OUT.Signal=RCC_OSC32_OUT
 PC6.GPIOParameters=GPIO_Speed
 PC6.GPIO_Speed=GPIO_SPEED_FREQ_LOW
@@ -128,10 +126,10 @@ PC7.GPIO_Speed=GPIO_SPEED_FREQ_LOW
 PC7.Mode=Asynchronous
 PC7.Signal=USART6_RX
 PH0\ -\ OSC_IN.Locked=true
-PH0\ -\ OSC_IN.Mode=HSE-External-Clock-Source
+PH0\ -\ OSC_IN.Mode=HSE-External-Oscillator
 PH0\ -\ OSC_IN.Signal=RCC_OSC_IN
 PH1\ -\ OSC_OUT.Locked=true
-PH1\ -\ OSC_OUT.Mode=HSE-External-Clock-Source
+PH1\ -\ OSC_OUT.Mode=HSE-External-Oscillator
 PH1\ -\ OSC_OUT.Signal=RCC_OSC_OUT
 PinOutPanel.RotationAngle=0
 ProjectManager.AskForMigrate=true
@@ -166,34 +164,36 @@ ProjectManager.UAScriptAfterPath=
 ProjectManager.UAScriptBeforePath=
 ProjectManager.UnderRoot=true
 ProjectManager.functionlistsort=1-SystemClock_Config-RCC-false-HAL-false,2-MX_GPIO_Init-GPIO-false-HAL-true,3-MX_USART2_UART_Init-USART2-false-HAL-true,4-MX_USART6_UART_Init-USART6-false-HAL-true,5-MX_I2C1_Init-I2C1-false-HAL-true,6-MX_USART1_UART_Init-USART1-false-HAL-true
-RCC.48MHZClocksFreq_Value=48000000
-RCC.AHBFreq_Value=84000000
-RCC.APB1CLKDivider=RCC_HCLK_DIV2
-RCC.APB1Freq_Value=42000000
-RCC.APB1TimFreq_Value=84000000
-RCC.APB2Freq_Value=84000000
-RCC.APB2TimFreq_Value=84000000
-RCC.CortexFreq_Value=84000000
-RCC.FCLKCortexFreq_Value=84000000
-RCC.HCLKFreq_Value=84000000
+RCC.48MHZClocksFreq_Value=36571428.571428575
+RCC.AHBFreq_Value=32000000
+RCC.APB1Freq_Value=32000000
+RCC.APB1TimFreq_Value=32000000
+RCC.APB2Freq_Value=32000000
+RCC.APB2TimFreq_Value=32000000
+RCC.CortexFreq_Value=32000000
+RCC.FCLKCortexFreq_Value=32000000
+RCC.HCLKFreq_Value=32000000
 RCC.HSE_VALUE=8000000
 RCC.HSI_VALUE=16000000
 RCC.I2SClocksFreq_Value=96000000
-RCC.IPParameters=48MHZClocksFreq_Value,AHBFreq_Value,APB1CLKDivider,APB1Freq_Value,APB1TimFreq_Value,APB2Freq_Value,APB2TimFreq_Value,CortexFreq_Value,FCLKCortexFreq_Value,HCLKFreq_Value,HSE_VALUE,HSI_VALUE,I2SClocksFreq_Value,LSI_VALUE,MCO2PinFreq_Value,PLLCLKFreq_Value,PLLN,PLLP,PLLQ,PLLQCLKFreq_Value,RTCFreq_Value,RTCHSEDivFreq_Value,SYSCLKFreq_VALUE,SYSCLKSource,VCOI2SOutputFreq_Value,VCOInputFreq_Value,VCOOutputFreq_Value,VcooutputI2S
+RCC.IPParameters=48MHZClocksFreq_Value,AHBFreq_Value,APB1Freq_Value,APB1TimFreq_Value,APB2Freq_Value,APB2TimFreq_Value,CortexFreq_Value,FCLKCortexFreq_Value,HCLKFreq_Value,HSE_VALUE,HSI_VALUE,I2SClocksFreq_Value,LSE_VALUE,LSI_VALUE,MCO2PinFreq_Value,PLLCLKFreq_Value,PLLM,PLLN,PLLP,PLLQ,PLLQCLKFreq_Value,PLLSourceVirtual,RTCFreq_Value,RTCHSEDivFreq_Value,SYSCLKFreq_VALUE,SYSCLKSource,VCOI2SOutputFreq_Value,VCOInputFreq_Value,VCOOutputFreq_Value,VcooutputI2S
+RCC.LSE_VALUE=32768
 RCC.LSI_VALUE=32000
-RCC.MCO2PinFreq_Value=84000000
-RCC.PLLCLKFreq_Value=84000000
-RCC.PLLN=336
-RCC.PLLP=RCC_PLLP_DIV4
+RCC.MCO2PinFreq_Value=32000000
+RCC.PLLCLKFreq_Value=32000000
+RCC.PLLM=8
+RCC.PLLN=256
+RCC.PLLP=RCC_PLLP_DIV8
 RCC.PLLQ=7
-RCC.PLLQCLKFreq_Value=48000000
+RCC.PLLQCLKFreq_Value=36571428.571428575
+RCC.PLLSourceVirtual=RCC_PLLSOURCE_HSE
 RCC.RTCFreq_Value=32000
 RCC.RTCHSEDivFreq_Value=4000000
-RCC.SYSCLKFreq_VALUE=84000000
+RCC.SYSCLKFreq_VALUE=32000000
 RCC.SYSCLKSource=RCC_SYSCLKSOURCE_PLLCLK
 RCC.VCOI2SOutputFreq_Value=192000000
 RCC.VCOInputFreq_Value=1000000
-RCC.VCOOutputFreq_Value=336000000
+RCC.VCOOutputFreq_Value=256000000
 RCC.VcooutputI2S=96000000
 SH.GPXTI13.0=GPIO_EXTI13
 SH.GPXTI13.ConfNb=1