STR720 datasheet(75/401 Pages) STMICROELECTRONICS

75 / 401 page

STR720 - WAKE-UP INTERRUPT UNIT (WIU)

75/401

sequence might start before entering STOP mode (consider the ARM7 three-stage pipeline).

In order to avoid to execute any valid instruction after a correct STOP bit setting sequence and

before entering the STOP mode, it is mandatory to execute a dummy set of few instructions

after the STOP bit setting sequence. In particular at least six dummy instructions (e.g.

MOV R1, R1) shall be added after the third valid writing operation in STOP bit. Again, if exiting

from STOP mode an interrupt routine shall be serviced, another set of dummy instructions

shall be added, to take into account of the latency period: this is evaluated in at least other

three dummy instructions. This to consider that when STOP mode entered, the pipeline

content is frozen as well, and when the system restarts the first executed instruction was

fetched and decoded before entering the STOP mode itself.

Bit 1 = INT_EN: Interrupt Channel Enable.

This bit is set and cleared by software.

0: Global mask for the 16 interrupt lines

1: The 16 external wake-up lines enabled as interrupt sources

WARNING: In order to avoid spurious interrupt requests on the Wake-up unit associated

channel in the interrupt controller, due to change of interrupt source, it is suggested to reset

the mask bit inside the interrupt controller before programming INT_EN bit as needed.

bit 0 = WKUP-INT: Wake-up Interrupt.

This bit is set and cleared by software.

0: The 16 external wake-up lines can be used to generate interrupt requests

1: The 16 external wake-up lines to work as wakeup sources for exiting from STOP mode

STR720 数据表(PDF) 75 Page - STMicroelectronics