ST7265XEVALMS STMicroelectronics, ST7265XEVALMS Datasheet - Page 45

• Manufacturer Part Number: ST7265XEVALMS
• Manufacturer: STMicroelectronics

Specifications of ST7265XEVALMS

• Lead Free Status / Rohs Status: Supplier Unconfirmed

POWER SAVING MODES (Cont’d)
8.3 HALT MODE
The HALT mode is the MCU lowest power con-
sumption mode. The HALT mode is entered by ex-
ecuting the HALT instruction. The internal oscilla-
tor is then turned off, causing all internal process-
ing to be stopped, including the operation of the
on-chip peripherals.
When entering HALT mode, the
Condition Code Register are cleared. Thus, any of
the external interrupts (ITi or USB end suspend
mode), are allowed and if an interrupt occurs, the
CPU clock becomes active.
The MCU can exit HALT mode on reception of ei-
ther an external interrupt on ITi, a plug/unplug in-
terrupt, an end suspend mode interrupt coming
from USB peripheral, an SPI interrupt or a reset.
The oscillator is then turned on and a stabilization
time is provided before releasing CPU operation.
The stabilization time is 512 CPU clock cycles.
After the start up delay, the CPU continues opera-
tion by servicing the interrupt which wakes it up or
by fetching the reset vector if a reset wakes it up.
Related Documentation
AN980: ST7 Keypad Decoding Techniques, Im-
plementing Wake-Up on Keystroke
AN1014: How to Minimize the ST7 Power Con-
sumption
AN1605: Using an active RC to wakeup the
ST7LITE0 from power saving mode
I[1:0] bits
in the
Figure 30. HALT Mode Flow Chart
Note: Before servicing an interrupt, the CC
register is pushed on the stack. The
set during the interrupt routine and cleared
when the CC register is popped.
N
INTERRUPT*
EXTERNAL
Y
OSCILLATOR
PERIPH. CLOCK
CPU CLOCK
I1:0] BITS
OR SERVICE INTERRUPT
OSCILLATOR
PERIPH. CLOCK
CPU CLOCK
I1:0] BITS
FETCH RESET VECTOR
(Refer to
N
HALT INSTRUCTION
Figure
DELAY
Figure 19
RESET
20)
Y
I1:0] bits
OFF
OFF
OFF
CLEARED
and
ON
ST7265x
ON
ON
SET
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