Workaround for an STM32F405 bug causing a delay between an RCC peripheral clock enable and the effective peripheral enabling, as described in ST's silicon errata sheet

platform/drivers/ADC/ADC1_MDxx380.c

@@ -25,6 +25,7 @@ void adc1_init()
 {
     RCC->APB2ENR |= RCC_APB2ENR_ADC1EN;
     RCC->AHB1ENR |= RCC_AHB1ENR_DMA2EN;
+    __DSB();
 
     /*
      * Configure GPIOs to analog input mode:
@@ -100,8 +101,9 @@ void adc1_init()
 void adc1_terminate()
 {
     DMA2_Stream0->CR &= ~DMA_SxCR_EN;
-    ADC1->CR2 &= ADC_CR2_ADON;
+    ADC1->CR2 &= ~ADC_CR2_ADON;
     RCC->APB2ENR &= ~RCC_APB2ENR_ADC1EN;
+    __DSB();
 }
 
 float adc1_getMeasurement(uint8_t ch)

platform/drivers/display/HX83XX_MDxx380.c

@@ -132,6 +132,8 @@ void display_init()
      * framebuffer content to the screen without using CPU.
      */
     RCC->AHB1ENR |= RCC_AHB1ENR_DMA2EN;
+    __DSB();
+
     NVIC_ClearPendingIRQ(DMA2_Stream7_IRQn);
     NVIC_SetPriority(DMA2_Stream7_IRQn, 14);
     NVIC_EnableIRQ(DMA2_Stream7_IRQn);
@@ -141,6 +143,7 @@ void display_init()
      * lines.
      */
     RCC->AHB3ENR |= RCC_AHB3ENR_FSMCEN;
+    __DSB();
 
     /* Configure FSMC as LCD driver.
      * BCR1 config:
@@ -331,6 +334,8 @@ void display_terminate()
 {
     /* Shut off FSMC and deallocate framebuffer */
     RCC->AHB3ENR &= ~RCC_AHB3ENR_FSMCEN;
+    __DSB();
+
     if(frameBuffer != NULL)
     {
         free(frameBuffer);

platform/drivers/tones/toneGenerator_MDxx380.c

@@ -106,6 +106,7 @@ void toneGen_init()
      * - Nominal update rate is 16.384kHz -> error = +22.25Hz
      */
     RCC->APB1ENR |= RCC_APB1ENR_TIM3EN;
+    __DSB();
 
     TIM3->ARR   = 0xFF;
     TIM3->PSC   = 9;
@@ -125,6 +126,8 @@ void toneGen_init()
 void toneGen_shutdown()
 {
     RCC->APB1ENR &= ~RCC_APB1ENR_TIM3EN;
+    __DSB();
+
     gpio_setMode(CTCSS_OUT, INPUT);
     gpio_setMode(BEEP_OUT,  INPUT);
 }

platform/mcu/STM32F4xx/boot/startup.c

@@ -59,6 +59,7 @@ void Reset_Handler()
                  |  RCC_AHB1ENR_GPIOCEN
                  |  RCC_AHB1ENR_GPIODEN
                  |  RCC_AHB1ENR_GPIOEEN;
+    __DSB();
 
     // Configure all GPIO pins to fast speed mode (50MHz)
     GPIOA->OSPEEDR = 0xAAAAAAAA;

platform/mcu/STM32F4xx/drivers/rtc.c

@@ -25,6 +25,8 @@ void rtc_init()
 {
     /* Enable write protection for RTC registers */
     RCC->APB1ENR |= RCC_APB1ENR_PWREN;
+    __DSB();
+
     PWR->CR |= PWR_CR_DBP;
     RTC->WPR = 0xCA;
     RTC->WPR = 0x53;

platform/mcu/STM32F4xx/drivers/usb/usb_bsp.c

@@ -58,6 +58,7 @@ void USB_OTG_BSP_Init(USB_OTG_CORE_HANDLE *pdev)
 
     RCC->APB2ENR |= RCC_APB2ENR_SYSCFGEN;
     RCC->AHB2ENR |= RCC_AHB2ENR_OTGFSEN;
+    __DSB();
 }
 
 /**

platform/targets/MD-380/platform.c

@@ -52,6 +52,8 @@ void platform_init()
      * Backlight pin is connected to TIM8 CR1.
      */
     RCC->APB2ENR |= RCC_APB2ENR_TIM8EN;
+    __DSB();
+
     TIM8->ARR = 255;
     TIM8->PSC = 327;
     TIM8->CNT = 0;
@@ -78,6 +80,7 @@ void platform_terminate()
 
     /* Shut down timer */
     RCC->APB2ENR &= ~RCC_APB2ENR_TIM8EN;
+    __DSB();
 
     /* Shut down ADC */
     adc1_terminate();

platform/targets/MD-390/platform.c

@@ -52,6 +52,8 @@ void platform_init()
      * Backlight pin is connected to TIM8 CR1.
      */
     RCC->APB2ENR |= RCC_APB2ENR_TIM8EN;
+    __DSB();
+
     TIM8->ARR = 255;
     TIM8->PSC = 327;
     TIM8->CNT = 0;
@@ -78,6 +80,7 @@ void platform_terminate()
 
     /* Shut down timer */
     RCC->APB2ENR &= ~RCC_APB2ENR_TIM8EN;
+    __DSB();
 
     /* Shut down ADC */
     adc1_terminate();

platform/targets/MD-UV380/platform.c

@@ -72,6 +72,8 @@ void platform_init()
      * With ARR = 256, Fpwm is 256Hz;
      */
     RCC->APB2ENR |= RCC_APB2ENR_TIM11EN;
+    __DSB();
+
     TIM11->ARR = 255;
     TIM11->PSC = 1282;
     TIM11->CNT = 0;
@@ -100,6 +102,7 @@ void platform_terminate()
 
     #ifdef ENABLE_BKLIGHT_DIMMING
     RCC->APB2ENR &= ~RCC_APB2ENR_TIM11EN;
+    __DSB();
     #endif
 
     /* Shut down LEDs */