HD6417615 Hitachi Semiconductor, HD6417615 Datasheet - Page 206

• Manufacturer Part Number: HD6417615
• Description: Hardware Manual
• Manufacturer: Hitachi Semiconductor

5.4
5.4.1
The sequence of operations in interrupt generation is described below and illustrated in figure 5.5.
1. The interrupt request sources send interrupt request signals to the interrupt controller.
2. The interrupt controller selects the highest-priority interrupt among the interrupt requests sent,
3. The interrupt controller compares the priority level of the selected interrupt request with the
4. The CPU detects the interrupt request sent from the interrupt controller when it decodes the
5. Status register (SR) and program counter (PC) are saved onto the stack.
6. The priority level of the accepted interrupt is copied to the interrupt mask level bits (I3 to I0) in
7. When external vector mode is specified for the IRL/IRQ interrupt, the vector number is read
8. The CPU reads the start address of the exception service routine from the exception vector
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according to the priority levels set in interrupt priority level setting registers A to E (IPRA–
IPRE). Lower-priority interrupts are held pending. If two or more of these interrupts have the
same priority level or if multiple interrupts occur within a single module, the interrupt with the
highest default priority or the highest priority within its IPR setting unit (as indicated in table
5.4) is selected.
interrupt mask bits (I3–I0) in the CPU’s status register (SR). If the request priority level is
equal to or less than the level set in I3–I0, the request is held pending. If the request priority
level is higher than the level in bits I3–I0, the interrupt controller accepts the interrupt and
sends an interrupt request signal to the CPU.
next instruction to be executed. Instead of executing the decoded instruction, the CPU starts
interrupt exception handling.
the status register (SR).
from the external vector number input pins (D7–D0).
table entry for the accepted interrupt, jumps to that address, and starts executing the program
there. This jump is not a delayed branch.
Interrupt Operation
Interrupt Sequence