Datasheet

DocID025083 Rev 7 25/121
STM32F303x6/x8 Functional overview
44
inaccuracy.
• Two anti-tamper detection pins with programmable filter. The MCU can be woken up
from Stop and Standby modes on tamper event detection.
• Timestamp feature, which can be used to save the calendar content. This function can
be triggered by an event on the timestamp pin, or by a tamper event. The MCU can be
woken up from Stop and Standby modes on timestamp event detection.
• 17-bit Auto-reload counter for periodic interrupt with wakeup from STOP/STANDBY
capability.
The RTC clock sources can be:
• A 32.768 kHz external crystal
• A resonator or oscillator
• The internal low-power RC oscillator (typical frequency of 40 kHz)
• The high-speed external clock divided by 32.
3.16 Communication interfaces
3.16.1 Inter-integrated circuit interface (I
2
C)
The devices feature an I
2
C bus interface that can operate in multimaster and slave mode. It
can support standard (up to 100
kHz), fast (up to 400 kHz) and fast mode + (up to 1 MHz)
modes.
It supports 7-bit and 10-bit addressing modes, multiple 7-bit slave addresses (2 addresses,
1 with configurable mask). It also includes programmable analog and digital noise filters.
In addition, it provides hardware support for SMBUS 2.0 and PMBUS 1.1: ARP capability,
Host notify protocol, hardware CRC (PEC) generation/verification, timeouts verifications and
ALERT protocol management. It also has a clock domain independent from the CPU clock,
allowing the I2C1 to wake up the MCU from Stop mode on address match.
The I
2
C interface can be served by the DMA controller.
The features available in I2C1 are showed below in Table 7.
Table 6. Comparison of I
2
C analog and digital filters
- Analog filter Digital filter
Pulse width of
suppressed spikes
≥ 50 ns
Programmable length from 1 to 15
I
2
C peripheral clocks
Benefits Available in Stop mode
1. Extra filtering capability vs.
standard requirements.
2. Stable length
Drawbacks
Variations depending on
temperature, voltage, process
Wakeup from Stop on address
match is not available when digital
filter is enabled.
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