PendSV Allows Simple and Efficient Context Switch on Cortex-M
Centralizing context switch logic in PendSV simplifies concurrency reasoning and enhances system performance by reducing register preservation overhead of all other exceptions.
SVC Can Be Invoked Asynchronously When Dynamically Changing Exception Priority on Cortex-M
SVC will be pended if a higher priority exception arrives during the stacking. If the priority of SVC is raised above the previously higher priority exception inside its handler, …
Read-Modify-Write On Self-Changing Registers Causes Trouble
Read-modify-write on the `cr1` register of I²C may generate two consecutive start condition and hang the peripheral.
Fix Rust Library stm32f4xx-hal Causing I²C to Hang When Using DMA
The Rust HAL Library `stm32f4xx-hal` failed to set the `LAST` bit in I²C `CR2` before initiating a DMA read. We tracked down the problem with a logic analyzer and identified the …
Resolving STM32F4xx I²C Stuck Busy After MCU Software Reset
The I²C bus may be stuck busy after a software reset if the slave peripheral is holding the SDA line upon reset. Manually generating some clock pulses on the SCL line and sending a …
Resolving STM32F4xx I²C Stuck Waiting for Address Sent
STM32F4xx I²C can be stuck after start condition when the stop bit is set while the I²C bus is already idle.
