| 1. For UART drivers in blocking mode, the readCancel() and writeCancel() | |
| post the UART object's readSem and writeSem. In FreeRTOS, there doesn't | |
| seem to be a way to know if we're in ISR context or not. In ISR context, | |
| SemOSAL_postFromISR() must be used instead of SemOSAL_post(). | |
| So we'll assume writeCancel() and readCancel() are not being called from | |
| ISR context and use SemOSAL_post(). |