M68HC08 datasheet(101/288 Pages) FREESCALE

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System Integration Module (SIM)

MC68HC908BD48 — Rev. 2.1

Data Sheet

Freescale Semiconductor

System Integration Module (SIM)

101

The LDA opcode is pre-fetched by both the INT1 and INT2 RTI

instructions. However, in the case of the INT1 RTI pre-fetch, this is a

redundant operation.

NOTE:

To maintain compatibility with the M6805 Family, the H register is not

pushed on the stack during interrupt entry. If the interrupt service routine

modifies the H register or uses the indexed addressing mode, software

should save the H register and then restore it prior to exiting the routine.

7.6.1.2 SWI Instruction

The SWI instruction is a non-maskable instruction that causes an

interrupt regardless of the state of the interrupt mask (I bit) in the

condition code register.

NOTE:

A software interrupt pushes PC onto the stack. A software interrupt does

not push PC – 1, as a hardware interrupt does.

7.6.2 Interrupt Status Registers

The flags in the interrupt status registers identify maskable interrupt

sources. Table 7-4 summarizes the interrupt sources and the interrupt

status register flags that they set. The interrupt status registers can be

useful for debugging.

M68HC08 数据表(PDF) 101 Page - Freescale Semiconductor, Inc