STM32L-DISCOVERY STMicroelectronics, STM32L-DISCOVERY Datasheet - Page 24

• Manufacturer Part Number: STM32L-DISCOVERY
• Description: BOARD, EVAL, STM32L-DISCOVERY
• Manufacturer: STMicroelectronics
• Series: STM32r
• Type: MCUr

Specifications of STM32L-DISCOVERY

• Kit Contents: Board, Debugger, Programmer And Compiler
• Features: 128KB Flash Plus Multiple Timers, Analogue Peripherals
• Silicon Manufacturer: ST Micro
• Core Architecture: ARM
• Core Sub-architecture: Cortex - M3
• Silicon Core Number: STM32
• Silicon Family Name: STM32F1xx
• Rohs Compliant: Yes
• Contents: Board
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: STM32L
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Description
2.2.18
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Figure 7.
Real-time clock (RTC), backup SRAM and backup registers
The backup domain of the STM32F205xx and STM32F207xx includes:
●
●
●
The real-time clock (RTC) is an independent BCD timer/counter. Dedicated registers contain
the second, minute, hour (in 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
performed automatically. The RTC provides a programmable alarm and programmable
periodic interrupts with wakeup from Stop and Standby modes.
It is clocked by a 32.768 kHz external crystal, resonator or oscillator, the internal low-power
RC oscillator or the high-speed external clock divided by 128. The internal low-speed RC
has a typical frequency of 32 kHz. The RTC can be calibrated using an external 512 Hz
output to compensate for any natural quartz deviation.
Two alarm registers are used to generate an alarm at a specific time and calendar fields can
be independently masked for alarm comparison. To generate a periodic interrupt, a 16-bit
programmable binary auto-reload downcounter with programmable resolution is available
and allows automatic wakeup and periodic alarms from every 120 µs to every 36 hours.
A 20-bit prescaler is used for the time base clock. It is by default configured to generate a
time base of 1 second from a clock at 32.768 kHz.
The backup SRAM size is 4 Kbytes and can be enabled by software. When the backup RAM
is enabled the power consumption in Standby or V
Section 2.2.19: Low-power
The backup registers are 32-bit registers used to store 80 bytes of user application data
when V
or when the device wakes up from the Standby mode (see
modes).
The RTC, backup RAM and backup registers are supplied through a switch that takes power
from either the V
The real-time clock (RTC)
4 Kbytes of backup SRAM
20 backup registers
DD
power is not present. Backup registers are not reset by a system, a power reset,
Startup in regulator OFF: fast V
- power-down reset risen before V
DD
supply when present or the V
modes).
Doc ID 15818 Rev 6
DD
CAP_1
BAT
slope
BAT
pin.
mode is slightly higher (see
/V
CAP_2
Section 2.2.19: Low-power
STM32F205xx, STM32F207xx
stabilization