FUJITSU FR family 32-bit microcontroller instruction manuel CM71-00101-5E User Manual

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CHAPTER 4 RESET AND "EIT" PROCESSING

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Time to Start of Interrupt Processing

The time required to start interrupt processing can be expressed as a maximum of "n + 6" cycles from the

start of the instruction currently executing when the interrupt was received, where "n" represents the

number of execution cycles in the instruction.

If the instruction includes memory access, or insufficient instructions are present, the corresponding

number of wait cycles must be added.

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"PC" Values Saved for Interrupts

When an interrupt is accepted by the processor, those instructions in the pipeline that cannot be interrupted

in time will be executed. The remainder of the instructions will be canceled, and will not be processed after

the interrupt. The "EIT" processing sequence saves "PC" values to the system stack representing the

addresses of canceled instructions.

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How to Use User Interrupts

The following programming steps must be set up to enable the use of user interrupts.

Figure 4.3-1 illustrates the use of user interrupts.

Figure 4.3-1 How to Use User Interrupts

(1) Enter values in the interrupt vector table (defined as data).

(2) Set up the "SSP" values.

(3) Set up the table base register (TBR) values.

(4) Within the interrupt controller, enter the appropriate level for the "ICR" corresponding to interrupts

from the peripheral from which the interrupt will originate.

(5) Initialize the peripheral function that requests the occurrence of the interrupt, and enable its interrupt

function.

(6) Set up the appropriate value in the "ILM" field in the "PS".

(7) Set the "I" flag to "1".

FR family CPU

SSP USP

ILM

INT
OK

AND

Comparator

Interrupt
controller

Peripheral
device

ICR#n

Interrupt
enable bit

Internal bus

(5)

(4)

(2)

(6)

(7)