Datasheet

Table Of Contents
DS13105 Rev 4 43/135
STM32WLE5J8/JB/JC Functional overview
46
The RTC is functional in VBAT mode.
Twenty 32-bit backup registers are retained in all low-power modes and also in VBAT mode.
These registers can be used to store sensitive data as their content is protected by a tamper
detection circuit.
Three tamper pins and four internal tampers are available for anti-tamper detection. The
external tamper pins can be configured for edge or level detection with or without filtering.
3.25 Inter-integrated circuit interface (I2C)
The device embeds three I2Cs, with features implementation listed in the he table below.
The I
2
C bus interface handles communications between the microcontroller and the serial
I
2
C bus. It controls all I
2
C bus-specific sequencing, protocol, arbitration and timing.
The I2C peripheral supports:
I
2
C bus specification and user manual rev. 5 compatibility:
slave and master modes, multimaster capability
Standard-mode (Sm), with a bitrate up to 100 Kbit/s
Fast-mode (Fm), with a bitrate up to 400 Kbit/s
Fast-mode plus (Fm+), with a bitrate up to 1 Mbit/s and 20 mA output drive I/Os
7-bit and 10-bit addressing mode, multiple 7-bit slave addresses
programmable setup and hold times
clock stretching (optional)
SMBus (system management bus) specification rev 2.0 compatibility:
hardware PEC (packet error checking) generation and verification with ACK
control
address resolution protocol (ARP) support
SMBus alert
PMBus (power system management protocol) specification rev 1.1 compatibility
independent clock: a choice of independent clock sources allowing the I
2
C
communication speed to be independent from the PCLK reprogramming (see Figure 7)
wakeup from Stop mode on address match
programmable analog and digital noise filters
1-byte buffer with DMA capability
Table 15. I2C implementation
I2C features
(1)
I2C1
(2)
I2C2
(2)
I2C3
7-bit addressing mode X X X
10-bit addressing mode X X X
Standard-mode (up to 100 Kbit/s) X X X
Fast-mode (up to 400 Kbit/s) X X X
Fast-mode Plus with 20mA output drive I/Os (up to 1 Mbit/s) X X X
Independent clock X X X