H8SLASH300H datasheet(77/552 Pages) RENESAS

Nome de Peças	H8/300H

Descrição Electrónicos	Renesas 16-Bit Single-Chip Microcomputer

PDF	552 Pages

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Fabricante Electrônico	RENESAS [Renesas Technology Corp]

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Section 3 Exception Handling

Rev. 3.00 May 15, 2007 Page 45 of 516

REJ09B0152-0300

Vector fetch

Internal

address bus

Internal read

signal

Internal write

signal

Internal data

bus (16 bits)

RES

Internal

processing

Initial program

instruction prefetch

(1) Reset exception handling vector address (H'0000)

(2) Program start address

(3) Initial program instruction

(2)

(3)

(2)

(1)

Reset cleared

Figure 3.1 Reset Exception Handling Sequence

3.2.2

Interrupt Immediately after Reset

Immediately after a reset, if an interrupt is accepted before the stack pointer (SP) is initialized, PC

and CCR will not be pushed onto the stack correctly, resulting in program runaway. To prevent

this, immediately after reset exception handling all interrupts are masked. For this reason, the

initial program instruction is always executed immediately after a reset. This instruction should

initialize the stack pointer (e.g. MOV.L #xx: 32, SP).

H8/300H Folha de dados(PDF) 77 Page - Renesas Technology Corp