Using Freescale K70 cpu with MDK 5 Rev. 5.14. Have enabled UART0 interrupt with CMSIS: "NVIC_EnableIRQ (UART0_RX_TX_IRQn);" Made an ISR "void UART0_RX_TX_IRQHandler (void){...}" Get Receive Interrupts from UART0 into this ISR, so far, so good. But: In µVision's Event Viewer window this ISR is flagged as "INT_CAN0_ORed_Message_buffer (61)"!?!. "UART0_RX_TX_IRQn" has value 45 in CMSIS header MK70F12.h "CAN0_ORed_Message_buffer_IRQn" has value 29 in CMSIS header MK70F12.h. Value 61 is assigned to "CMP2_IRQn" in CMSIS header MK70F12.h. 29 is 45 - 16 and 61 is 45 + 16. This led me to (my thought) a very unclear documentation of "IRQn" values and the 16 offset. Seems programmer of µVision Event Viewer window fell in same hole (seems he does "-16" for ISRn). Best regards Juergen.