NEC PD75402A - Manual (Page 137)

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CHAPTER 6. INTERRUPT FUNCTIONS
CHAPTER 6. INTERRUPT FUNCTIONS
On the
µ
PD75402A there are 3 vectored interrupt sources and one testable input, enabling a wide variety of
applications to be handled.
Moreover, the
µ
PD75402A’s interrupt control circuit has the following special features, making possible
extremely fast interrupt servicing.
(a) Acknowledgment enabling/disabling is possible by means of the interrupt master enable flag (IME) and
the interrupt enable flag (IE
×××
).
(b) Any desired interrupt service start address can be set using the vector table (for rapid starting of the actual
interrupt service program).
(c) Interrupt request flag (IRQ
×××
) can be tested and cleared (allowing checking of interrupt generation by
software).
(d) Standby mode (HALT) can be released by an interrupt request (release source is selectable from other than
INT0 by means of interrupt enable flag).
6.1 INTERRUPT CONTROL CIRCUIT CONFIGURATION
The interrupt control circuit is configured as shown in Fig. 6-1, with each hardware item mapped onto data
memory space.