The reference manual (RM0432) for the STM32L4R5 shows that UART4 & UART5 support two 8-byte FIFOs. I can't figure out how to configure the IRQ level thresholds. CubeMX shows levels for LPUART1 and USART1/2/3, but not UART4/5."Table 264. USART/LPUART ...