INTERNAL SPECIFICATIONS

4.7.2 Interrupt enable register (IE)

The function of the interrupt enable register (IE, 0A8H) is to enable or disable interrupt processes when an interrupt is requested.

To execute the intended interrupt routine, the interrupt is first enabled by setting “1” in the corresponding interrupt bit in the interrupt enable register, and the routine then is executed when the interrupt is requested.

Requested interrupts are disabled if the corresponding interrupt bit is “0”, and no interrupt routines are executed.

The contents of the interrupt enable register (IE) are shown in Table 4-19.

Table 4-19 lnterrupt enable register (IE, 0A8H)

 

Bit

 

7

6

5

4

3

2

1

0

 

 

 

 

 

 

 

 

 

 

 

 

Flag

 

EA

ET2

ES

ET1

EX1

ET0

EX0

 

 

 

 

 

 

 

 

 

 

 

EX0

:

External interrupt 0 control bit

 

 

 

 

 

 

 

Interrupt enabled when “1”, disabled when “0”.

 

 

 

ET0

:

Timer interrupt 0 control bit

 

 

 

 

 

 

 

Interrupt enabled when “1”, disabled when “0”.

 

 

 

EX1

:

External interrupt 1 control bit

 

 

 

 

 

 

 

Interrupt enabled when “1”, disabled when “0”.

 

 

 

ET1

:

Timer interrupt 1 control bit

 

 

 

 

 

 

 

Interrupt enabled when “1”, disabled when “0”.

 

 

 

ES

:

Serial port interrupt control bit

 

 

 

 

 

 

 

Interrupt enabled when “1”, disabled when “0”.

 

 

 

ET2

:

Timer interrupt 2 control bit

 

 

 

 

 

 

 

Interrupt enabled when “1”, disabled when “0”.

 

 

 

: Reserve bit for output of “1” when read.

EA : Interrupt control bit for all six interrupts (EX0, ET0, EX1, ET1, ES, and ET2) When EA is “1”, an interrupt routine is commenced if interrupt conditions are met for any one of the six interrupts.

When EA is “0”, no interrupt routine is commenced even if interrupt conditions are met for one of the six interrupts.

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Sonic Alert msm83c154s, msm80154s, msm85c154hvs user manual ET1, lnterrupt enable register IE, 0A8H