NEC PD75402A Interrupt Functions Interrupt Source Types and Vector Table, VEN T1 GOT OBT

CHAPTER 6. INTERRUPT FUNCTIONS

6.2INTERRUPT SOURCE TYPES AND VECTOR TABLE

The μPD75402A’s interrupt source types and interrupt vector table are shown in Table 6-1 and Fig. 6-2.

Table 6-1 Interrupt Request Source Types

Interrupt Request	Internal/	Interrupt	Vectored Interrupt Request Signal
Generation Source	External	Priority*1	(Vector Table Address)
INTBT	Internal	1	VRQ1(0002H)
(Basic time interval signal from basic interval timer)
INT0 (INT0 pin input specified edge detection)	External	2	VRQ2(0004H)
INTCSI (Serial data transfer termination signal)	Internal	3	VRQ3(0008H)
INT2*2 (INT2 pin input rising edge detection)	External	Testable input signal (sets) IRQ2 flag)

*1. The interrupt priority is the order of precedence when multiple interrupt requests occur simultaneously.

★2. A test source. This is affected by an interrupt enable flag in the same way as an interrupt source, but no vectored interrupt is generated.

Fig. 6-2 Interrupt Vector Table

Address
0 0 0 2 H	0	0	0	0	0	INTBT start address (high-order 3 bits)
						INTBT start address (low-order 8 bits)
0 0 0 4 H	0	0	0	0	0	INT0 start address (high-order 3 bits)
						INT0 start address (low-order 8 bits)

0 0 0 8 H	0	0	0	0	0	INTCSI start address (high-order 3 bits)
						INTCSI start address (low-order 8 bits)

The interrupt priority shown in the table shows the order in which interrupts are executed when multiple interrupt

requests are generated simultaneously or when multiple interrupt requests are pending.

The vector table contains the interrupt service routine start addresses. Vector table setting is performed by the

VENTn assembler pseudoinstruction.

Example INTBT vector table setting.

VENT1	GOTOBT
−	−
Address 0002	Symbol indicating start address
vector table	of interrupt service routine

Note The vector table address specified by VENTn (n = 1, 2 and 4) is address 2n.

Example INTBT and INT0 vector table setting.

VENT1 GOTOBT

VENT2 GOTO0

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