Merge pull request #28 from enzoevers/24-improve-performance-for-gpio…

…-toggling

[Ready] Configure PLL for STM32

Code/HardwareSetup/stm32/Stm32f303xc/src/SetupHardwareStm32f303xc.cpp

@@ -41,9 +41,37 @@ static auto SetupClock() -> void {
     // HLCK - SYSCLK not divided
     RCC->CFGR &= ~RCC_CFGR_HPRE_3;
 
-    // Select HSI for SYSCLOCK
-    RCC->CFGR &= ~RCC_CFGR_SW_0;
-    RCC->CFGR &= ~RCC_CFGR_SW_1;
+    //----------
+    // PLL
+    //----------
+
+    // Stop PLL
+    RCC->CR &= ~RCC_CR_PLLON;
+    while (RCC->CR & RCC_CR_PLLRDY) {
+    }
+
+    // Use HSI/2 as the PLL source clock
+    RCC->CFGR |= RCC_CFGR_PLLSRC_HSI_DIV2;
+
+    // Max allowed frequency is 72MHz.
+    // With a PLL input frequency of 4MHz (HSI/2 = 8MHz / 2 = 4MHz)
+    // the max multiplication is 72 / 4 = 18
+
+    // PLL multiplication
+    // SYSCLOCK = 4MHz * 10 = 40MHz
+    RCC->CFGR |= RCC_CFGR_PLLMUL10;
+
+    // Enable PLL
+    RCC->CR |= RCC_CR_PLLON;
+    while (!(RCC->CR & RCC_CR_PLLRDY)) {
+    }
+
+    //----------
+    // Main clock
+    //----------
+
+    // Select PLL for SYSCLOCK
+    RCC->CFGR |= RCC_CFGR_SW_PLL;
 
     // Enable HSI clock
     RCC->CR |= RCC_CR_HSION;

Code/main.cpp

@@ -42,7 +42,7 @@ int main() {
         latch.SetupConfiguration({&GPIOD->ODR, GPIO_ODR_14});
         ledOE.SetupConfiguration({&GPIOD->ODR, GPIO_ODR_15});
     }
-    uint32_t tim3Hertz = 8000000;
+    uint32_t tim3Hertz = 40000000;
     auto mainDelay = DelayStm32();
     mainDelay.SetupConfiguration({&TIM3->SR, &TIM3->ARR, &TIM3->CR1, &TIM3->PSC, tim3Hertz, TIM_SR_UIF, TIM_CR1_CEN});
 #endif
@@ -70,7 +70,6 @@ int main() {
 
     auto mainDelay = DelayDesktop();
 #endif
-
     HanoverOL037A_GPIOInterface hanoverOL037A_GPIOInterface{&clk, &clkEn, &clkSelEn, &data, &latch, &ledOE};
 
     auto hanoverOL037A = HanoverOL037A();

Scripts/Stm32/Stm32f303xc/StLinkFlash.sh

@@ -15,4 +15,4 @@ ValidateFileExists ${BINARY_PATH}
 
 WRITE_ADDRESS=0x8000000
 
-st-flash write ${BINARY_PATH} ${WRITE_ADDRESS}
+st-flash --reset write ${BINARY_PATH} ${WRITE_ADDRESS}