Datasheet

Section 4 Exception Handling
Page 104 of 1408 R01UH0309EJ0500 Rev. 5.00
Sep 24, 2012
H8S/2456, H8S/2456R, H8S/2454 Group
4.5 Interrupt Exception Handling
Interrupts are controlled by the interrupt controller. The interrupt controller has two interrupt
control modes and can assign interrupts other than NMI to eight priority/mask levels to enable
multiplexed interrupt control. The source to start interrupt exception handling and the vector
address differ depending on the product. For details, refer to section 5, Interrupt Controller.
The interrupt exception handling is as follows:
1. The values in the program counter (PC), condition code register (CCR), and extended register
(EXR) are saved in the stack.
2. The interrupt mask bit is updated and the T bit is cleared to 0.
3. A vector address corresponding to the interrupt source is generated, the start address is loaded
from the vector table to the PC, and program execution starts from that address.