Seems like the Interrupt flag for a Capture/Compare channel gets set when
- the CC-value is reached
- the timer resets before the CC value is reached.
We only want the first event and ignore the second one. Unfortunately I did
not find a way to disable the second event type, so it is filtered in software.
That is we need to
- ignore the CC-interrupts when the COUNT register register is reset
- ignore the CC-interrupts > TOP value/ARR (auto-reload register)
The STM32 line of microcontrollers comes with a bootloader in the ROM.
It provides the option to flash the device firmware in DFU mode (USB)
or via UART or SPI.
To enter the bootloader we have to jump to a specific address in memory,
but before reset the CPU to make sure the system is in a known state.
This enables us to use the usb_board_reset module on all STM32 platforms.
All members of the stm32f401* family (etc) don't have the HWRNG
peripheral.
Apply a broader wildcard so we don't have to touch this file when
adding new boards with slightly different MCUs.
The old limitation is not valid anymore, we can evaluate $(CPU_MODEL)
here directly.
The output of
make -C tests/periph_hwrng info-boards-supported | wc -w
remains the same.
