Texas Instruments MSP430x4xx User Manual

Page 74

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Instruction Set

3-40

RISC 16−Bit CPU

* EINT

Enable (general) interrupts

Syntax

EINT

Operation

1

GIE

or
(0008h .OR. SR −> SR / .src .OR. dst −> dst)

Emulation

BIS

#8,SR

Description

All interrupts are enabled.
The constant #08h and the status register SR are logically ORed. The result
is placed into the SR.

Status Bits

Status bits are not affected.

Mode Bits

GIE is set. OSCOFF and CPUOFF are not affected.

Example

The general interrupt enable (GIE) bit in the status register is set.

; Interrupt routine of ports P1.2 to P1.7
; P1IN is the address of the register where all port bits are read. P1IFG is the address of
; the register where all interrupt events are latched.
;

PUSH.B

&P1IN

BIC.B

@SP,&P1IFG

; Reset only accepted flags

EINT

; Preset port 1 interrupt flags stored on stack
; other interrupts are allowed

BIT

#Mask,@SP

JEQ

MaskOK

; Flags are present identically to mask: jump

......

MaskOK

BIC

#Mask,@SP

......
INCD

SP

; Housekeeping: inverse to PUSH instruction
; at the start of interrupt subroutine. Corrects
; the stack pointer.

RETI

Note:

Enable Interrupt

The instruction following the enable interrupt instruction (EINT) is always
executed, even if an interrupt service request is pending when the interrupts
are enable.

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