Added file with clock settings for STM32-F7 CPUs with a core clock of 216MHz,
an external high speed clock of 8 MHz and external low speed clock (32.768kHz)
enabled.
A common configuration file is introduced for stm32f4 with core clock
at 168MHz with HSE at 8MHz, 2 configuration files are introduced to²:
distinguish between clock configuration with and without LSE.
This commit add the connect_assert_srst which requires the SRST to be asserted before trying to connect.
Certain firmwares will cause it to get to a state where flashing fails and the reset button must be pushed at the correct time to recover.
