MPD784036 datasheet(41/90 Pages) NEC

41 / 90 page

µPD784031

9. INTERRUPT FUNCTION

Table 9-1 lists the interrupt request handling modes. These modes are selected by software.

Table 9-1. Interrupt Request Handling Modes

9.1

Interrupt Source

An interrupt can be issued from any one of the interrupt sources listed in Table 9-2: execution of BRK and BRKCS

instructions, an operand error, or any of the 23 other interrupt sources.

Four levels of interrupt handling priority can be set. Priority levels can be set to nest control during interrupt handling

or to concurrently generate interrupt requests. Nested macro services, however, are performed without suspension.

When interrupt requests having the same priority level are generated, they are handled according to the default

priority (fixed). (See Table 9-2.)

Handling mode

Handled by

Handling

PC and PSW contents

Vectored interrupt

Software

Branches to a handling routine for execution

The PC and PSW contents are pushed

(arbitrary handling).

to and popped from the stack.

Context switching

Automatically selects a register bank, and

The PC and PSW contents are saved to

branches to a handling routine for execution

and read from a fixed area in the

(arbitrary handling).

Macro service

Firmware

Performs operations such as memory-to-I/O-

Maintained

device data transfer (fixed handling).

MPD784036 Datasheet(PDF) 41 Page - NEC