R01UH0822EJ0100 Rev.1.00
Page 73 of 1041
Jul 31, 2019
RX13T Group
2. CPU
2.8.4
Numbers of Cycles for Response to Interrupts
lists numbers of cycles taken by processing for response to interrupts.
Times calculated from the values in
will be applicable when access to memory from the CPU is processed
with no waiting. The ROM and RAM in products of this MCU allow such access. Numbers of cycles for response to
interrupts can be minimized by placing program code (and vectors) in ROM and the stack in RAM. Furthermore, place
the addresses where the exception handling routine start on 8-byte boundaries.
For information on the number of cycles from notification to acceptance of the interrupt request, indicated by N in the
table above, see
Table 2.13, Instructions that are Converted into a Single Micro-Operation
Instructions that are Converted into Multiple Micro-Operations
The timing of interrupt acceptance depends on the state of the pipelines. For more information on this, refer to
13.3.1, Acceptance Timing and Saved PC Value
Table 2.15
Numbers of Cycles for Response to Interrupts
Type of Interrupt Request/Details of Processing
Fast Interrupt
Other Interrupts
ICU
Judgment of priority order
2 cycles
CPU
Number of cycles from notification to acceptance of
the interrupt request
N cycles
(varies with the instruction being executed at the time the interrupt was
received)
CPU Pre-processing by hardware
Saving the current PC and PSW values in RAM
(or in control registers in the case of the fast interrupt)
Reading of the vector
Branching to the start of the exception handling
routine
4 cycles
6 cycles