2025-11-30 3:13 AM
Hi,
On STM32G071CBU6, when PB15 is used as CC2 with DBCC2 shorted to CC2, does the ROM bootloader ever drive PB15 as SPI2_MOSI, or does the CC/dead-battery own the CC2 pin and that path always takes priority?
This detail is critical for our design because the device is bus-powered and relies on the dead-battery path to manage initial power-up. If the bootloader were to override PB15 and drive it as SPI2_MOSI while the flash is blank, it could cause a power drop when the ROM bootloader starts.
I checked the datasheet, reference manual, programming manual, and bootloader manual, and none of them explicitly state how the ROM bootloader handles SPI2_MOSI when that pad is also CC2 with DBCC shorted.
Could you please clarify?
Thanks