ST7FLU05MCE View Datasheet(PDF) - STMicroelectronics

Part Name

Description

MFG CO.

ST7FLU05MCE

8-bit low cost, low pin-count MCU for automotive, with single voltage Flash memory, ADC, timers

STMicroelectronics 

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Power saving modes

ST7LUS5, ST7LU05, ST7LU09

Halt mode recommendations

● Make sure that an external event is available to wake up the microcontroller from Halt

mode.

● When using an external interrupt to wake up the microcontroller, re-initialize the

corresponding I/O as “input pull-up with interrupt” before executing the HALT

instruction. The main reason for this is that the I/O may be wrongly configured due to

external interference or by an unforeseen logical condition.

● For the same reason, re-initialize the level sensitiveness of each external interrupt as a

precautionary measure.

● The opcode for the HALT instruction is 0x8E. To avoid an unexpected HALT instruction

due to a program counter failure, it is advised to clear all occurrences of the data value

0x8E from memory. For example, avoid defining a constant in ROM with the value

) 0x8E.

t(s ● As the HALT instruction clears the I bit in the CC register to allow interrupts, the user

c may choose to clear all pending interrupt bits before executing the HALT instruction.

u This avoids entering other peripheral interrupt routines after executing the external

d interrupt routine corresponding to the wake-up event (reset or external interrupt).

te Pro ct(s) 8.5

Auto wake-up from halt mode

le du Auto Wake-up from Halt (AWUFH) mode is similar to halt mode with the addition of a

so ro specific internal RC oscillator for wake-up (auto wake-up from halt oscillator) which replaces

b P the main clock which was active before entering halt mode. Compared to Active Halt mode,

- O te AWUFH has lower power consumption (the main clock is not kept running), but there is no

accurate real-time clock available.

t(s) ole It is entered by executing the HALT instruction when the AWUEN bit in the AWUCSR

s register has been set.

uc Ob Figure 24. AWUFH mode block diagram

Prod t(s) - AWU RC

oscillator

lete uc fAWU_RC

to 8-bit timer input capture

Obso te Prod /64

Obsole divider

AWUFH

AWUFH

interrupt

prescaler/1 .. 255 (ei0 source)

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