ST6285BQ1 View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

ST6285BQ1

8-BIT OTP/EPROM MCU WITH LCD DRIVER, EEPROM AND A/D CONVERTER

STMicroelectronics 

ST62T85B/E85B

POWER SAVING MODE (Cont’d)

3.5.3 Exit from WAIT and STOP Modes

tered will be completed, starting with the

The following paragraphs describe how the MCU

exits from WAIT and STOP modes, when an inter-

rupt occurs (not a Reset). It should be noted that

the restart sequence depends on the original state

of the MCU (normal, interrupt or non-maskable in-

execution of the instruction which follows the

STOP or the WAIT instruction, and the MCU is

still in the interrupt mode. At the end of this rou-

tine pending interrupts will be serviced in accord-

ance with their priority.

terrupt mode) prior to entering WAIT or STOP – In the event of a non-maskable interrupt, the

mode, as well as on the interrupt type.

non-maskable interrupt service routine is proc-

Interrupts do not affect the oscillator selection.

essed first, then the routine in which the WAIT or

STOP mode was entered will be completed by

3.5.3.1 Normal Mode

executing the instruction following the STOP or

If the MCU was in the main routine when the WAIT

or STOP instruction was executed, exit from Stop

WAIT instruction. The MCU remains in normal

interrupt mode.

or Wait mode will occur as soon as an interrupt oc- Notes:

curs; the related interrupt routine is executed and,

on completion, the instruction which follows the

STOP or WAIT instruction is then executed, pro-

) viding no other interrupts are pending.

t(s 3.5.3.2 Non Maskable Interrupt Mode

c If the STOP or WAIT instruction has been execut-

u ed during execution of the non-maskable interrupt

d routine, the MCU exits from the Stop or Wait mode

ro as soon as an interrupt occurs: the instruction

P which follows the STOP or WAIT instruction is ex-

ecuted, and the MCU remains in non-maskable in-

te terrupt mode, even if another interrupt has been

le generated.

o 3.5.3.3 Normal Interrupt Mode

bs If the MCU was in interrupt mode before the STOP

or WAIT instruction was executed, it exits from

O STOP or WAIT mode as soon as an interrupt oc-

- curs. Nevertheless, two cases must be consid-

) ered:

t(s – If the interrupt is a normal one, the interrupt rou-

Obsolete Produc tine in which the WAIT or STOP mode was en-

To achieve the lowest power consumption during

RUN or WAIT modes, the user program must take

care of:

– configuring unused I/Os as inputs without pull-up

(these should be externally tied to well defined

logic levels);

– placing all peripherals in their power down

modes before entering STOP mode;

When the hardware activated Watchdog is select-

ed, or when the software Watchdog is enabled, the

STOP instruction is disabled and a WAIT instruc-

tion will be executed in its place.

If all interrupt sources are disabled (GEN low), the

MCU can only be restarted by a Reset. Although

setting GEN low does not mask the NMI as an in-

terrupt, it will stop it generating a wake-up signal.

The WAIT and STOP instructions are not execut-

ed if an enabled interrupt request is pending.

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