TIM6 & DAC question on STM32F469I-DISCO board

[testcode99]

Using STM32 CubeMX ver 6.9.2, if you start a new project using STM32F469I-DISCO board and choose Yes to set all peripherals to their default settings, TIM6 comes up disabled/gray. Why is that? Instead of pinout view, choosing system view, only shows TIM1 in use.

Second question on DAC. If DAC output 1 or 2 is enabled, NVIC settings shows TIM6 global interrupt, DAC1 and DAC2 underrun interrupt is automatically enabled & no way to disable it. When testing, even before HAL_init() completes, TIM6_DAC_IRQHandler starts going off. Why is that & how to stop it?

[Sarra.S]

Hello @testcode99, 

Thank you for your feedback, 

Regarding the first question, TIM6 is grayed/not available because it's already used for the system time base- that's why, TIM6 global interrupt is enabled, and TIM1 is the only timer used by default in the board's firmware. 

Concerning the DAC interrupt, it is also grayed because there are some conflicts between DAC outputs and other pins configured in default mode. 

You can always clear all pinouts and you won't face this case anymore. 

 

 

[testcode99]

Thank you, @Sarra.S, for the info.

In my case, easiest solution on STM32F469I-DISCO / 32F469IDISCOVERY board was to move system wake-up timebase to TIM7, instead of default TIM6. That prevents TIM6 interrupt from being always enabled & interfering with DAC activity. It would be nice if STM32Cube MX system view showed the TIM pulled to be used for system wake-up -- it doesnt do so currently. Just "SYS" is shown.

[RDund.1]

Hi, another annoying thing in CubeIDE is if the FreeRTOS is in use, and user is enabling DAC, interupt for TIM6 changes priority from 0 (default in new project) to 5 due to settings in FreeRTOS section, causing the system not to start. FreeRTOS only allows priorities 1-15, default 5, so without moving system timebase to another timer, one is stuck with bricked project as priority is now can not be reset to 0 in .ioc using CubeIDE - remember to make Backups, guys.

Thank you, testcode99, for solution.Interrupts before enabling DACPup up after enabling DACInterrupts after enabling DAC