ST7DALIF2 STMicroelectronics, ST7DALIF2 Datasheet - Page 56

• Manufacturer Part Number: ST7DALIF2
• Description: 8-BIT MCU WITH SINGLE VOLTAGE FLASH MEMORY, DATA EEPROM, ADC, TIMERS, SPI
• Manufacturer: STMicroelectronics

Specifications of ST7DALIF2

• 8 Kbytes Single Voltage Flash Program Memory With Read-out Protection, In-circuit Programming And In-application Programming (icp And Iap). 10k Write/erase Cycles Guaranteed, Data Retention: 20 years at 55°C.
• 256 Bytes Data Eeprom With Read-out Protection. 300k Write/erase Cycles Guaranteed, Data Retention: 20 years at 55°C.
• Clock Sources: Internal 1% RC oscillator, crystal/ceramic resonator or external clock
• Five Power Saving Modes: Halt, Active-Halt, Wait and Slow, Auto Wake Up From Halt

Power saving modes
11.6
56/171
Auto wakeup from Halt mode
Auto Wake Up From Halt (AWUFH) mode is similar to Halt mode with the addition of a
specific internal RC oscillator for wake-up (Auto Wake Up from Halt Oscillator). Compared to
Active-halt mode, AWUFH has lower power consumption (the main clock is not kept running,
but there is no accurate real-time clock available.
It is entered by executing the HALT instruction when the AWUEN bit in the AWUCSR
register has been set.
Figure 27. AWUFH mode block diagram
As soon as Halt mode is entered, and if the AWUEN bit has been set in the AWUCSR
register, the AWU RC oscillator provides a clock signal (f
a fixed divider and a programmable prescaler controlled by the AWUPR register. The output
of this prescaler provides the delay time. When the delay has elapsed the AWUF flag is set
by hardware and an interrupt wakes-up the MCU from Halt mode. At the same time the main
oscillator is immediately turned on and a 256 or 4096 cycle delay is used to stabilize it. After
this start-up delay, the CPU resumes operation by servicing the AWUFH interrupt. The AWU
flag and its associated interrupt are cleared by software reading the AWUCSR register.
To compensate for any frequency dispersion of the AWU RC oscillator, it can be calibrated
by measuring the clock frequency f
Measurement mode is enabled by setting the AWUM bit in the AWUCSR register in Run
mode. This connects f
the f
Similarities with Halt mode
The following AWUFH mode behavior is the same as normal Halt mode:
●
●
●
AWU_RC
The MCU can exit AWUFH mode by means of any interrupt with exit from Halt
capability or a reset (see
When entering AWUFH mode, the I bit in the CC register is forced to 0 to enable
interrupts. Therefore, if an interrupt is pending, the MCU wakes up immediately.
In AWUFH mode, the main oscillator is turned off causing all internal processing to be
stopped, including the operation of the on-chip peripherals. None of the peripherals are
to be measured using the main oscillator clock as a reference timebase.
f
AWU_RC
AWU RC
AWU_RC
oscillator
divider
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Section 11.4: Halt
to the input capture of the 12-bit Auto-Reload timer, allowing
AWU_RC
prescaler/1 .. 255
to Timer input capture
AWUFH
and then calculating the right prescaler value.
mode).
AWU_RC
(ei0 source)
AWUFH
interrupt
). Its frequency is divided by
ST7DALIF2