CHAPTER 6. INTERRUPT FUNCTIONS

CHAPTER 6. INTERRUPT FUNCTIONS

On the μPD75402A there are 3 vectored interrupt sources and one testable input, enabling a wide variety of applications to be handled.

Moreover, the μPD75402A’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).

6.1INTERRUPT CONTROL CIRCUIT CONFIGURATION

The interrupt control circuit is configured as shown in Fig. 6-1, with each hardware item mapped onto data memory space.

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NEC PD75402A, PD75P402 user manual Interrupt Functions