Hardware Interrupt Processing Time - Fujitsu F2MC-16LX Hardware Manual

CHAPTER 3 INTERRUPT
3.4.5

Hardware Interrupt Processing Time

Before the interrupt handling routine can be executed after a hardware interrupt request
is generated, the time to complete of the currently active instruction and the interrupt
handling time are required.
Hardware Interrupt Processing Time
Before the interrupt handling routine can be executed after an interrupt request is generated and the
interrupt is accepted, the waiting time for the interrupt request sample and the interrupt handling time
(required for preparation for interrupt handling) are required. Figure 3.4-6 shows the interrupt handling
time.
Operation of CPU
Interrupt wait time
Interrupt request generation
*
Interrupt request sampling wait time
The wait time for an interrupt request sample refers to the time from generation of an interrupt request to
the completion of the currently active instruction. Whether or not an interrupt request is present is
determined by interrupt request sampling in the final cycle of each instruction. Because the CPU cannot
recognize the interrupt request for the above reason, the wait time is produced.
The wait time for an interrupt request sample reaches the maximum if an interrupt request is generated
immediately after the start of the PCPW, PW0,..., RW7 instructions with the longest cycle of execution (45
machine cycle).
70
Figure 3.4-6 Interrupt Processing Time
Normal instruction execute
Interrupt request
sampling wait time
: The last cycle, Sampling interrupt request here
: 1 machine cycle is appropriate 1 clock cycle of machine clock (φ).
Interrupt handling
Inaterrupt handling time
(φ machine cycle)*
Interrupt
processing routine