STM32L152C6 datasheet(22/121 Pages) STMICROELECTRONICS

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Functional overview

STM32L151x6/8/B, STM32L152x6/8/B

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Doc ID 17659 Rev 8

3.5

Low power real-time clock and backup registers

The real-time clock (RTC) is an independent BCD timer/counter. Dedicated registers contain

the second, minute, hour (12/24 hour), week day, date, month, year, in BCD (binary-coded

decimal) format. Correction for 28, 29 (leap year), 30, and 31 day of the month are made

automatically. The RTC provides a programmable alarm and programmable periodic

interrupts with wakeup from Stop and Standby modes.

●

The programmable wakeup time ranges from 120 µs to 36 hours

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Stop mode consumption with LSI and Auto-wakeup: 1.2 µA (at 1.8 V) and 1.4 µA (at

3.0 V)

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Stop mode consumption with LSE, calendar and Auto-wakeup: 1.3 µA (at 1.8V), 1.6 µA

(at 3.0 V)

The RTC can be calibrated with an external 512 Hz output, and a digital compensation

circuit helps reduce drift due to crystal deviation.

There are twenty 32-bit backup registers provided to store 80 bytes of user application data.

They are cleared in case of tamper detection.

3.6

GPIOs (general-purpose inputs/outputs)

Each of the GPIO pins can be configured by software as output (push-pull or open-drain), as

input (with or without pull-up or pull-down) or as peripheral alternate function. Most of the

GPIO pins are shared with digital or analog alternate functions, and can be individually

remapped using dedicated AFIO registers. All GPIOs are high current capable. The

alternate function configuration of I/Os can be locked if needed following a specific

sequence in order to avoid spurious writing to the I/O registers. The I/O controller is

connected to the AHB with a toggling speed of up to 16 MHz.

External interrupt/event controller (EXTI)

The external interrupt/event controller consists of 23 edge detector lines used to generate

interrupt/event requests. Each line can be individually configured to select the trigger event

(rising edge, falling edge, both) and can be masked independently. A pending register

maintains the status of the interrupt requests. The EXTI can detect an external line with a

pulse width shorter than the Internal APB2 clock period. Up to 83 GPIOs can be connected

to the 16 external interrupt lines. The 7 other lines are connected to RTC, PVD, USB or

Comparator events.

STM32L152C6 Datasheet(PDF) 22 Page - STMicroelectronics