We are using LPC11E67JBD100 processor that has a combined interrupt slot for USART 2 & USART 3. When USART 2 is disabled and USART 3 is enabled, USART 3 works fine and vice versa. However since both have same the interrupt sources, they are not working simultaneously. I have tried keeping them at different baud rates. The breakpoint (in debugging mode) does not stop in the USART2_3 interrupt handler. Please suggest suitable line of action.