System Architecture; Figure 4. Steval-Smartag2 Architecture And Communication Paths - ST STEVAL-SMARTAG2 User Manual

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System architecture

The microcontroller is the system hub. It communicates with and controls every component in the system.
ST25DV64KC
• GPO general purpose output, which can be configured to signal RF events to the host microcontroller (field
change, memory write, RF activity, fast transfer end, user set/reset/pulse). This is useful to avoid conflicts
in the communication protocols when the dynamic tag is accessed simultaneously via RF and via I²C (the
microcontroller can wait for no RF activity before accessing the EEPROM).
• low-power down (LPD), set by the microcontroller when the
lowest power mode (typical 0.84 µA, maximum 1.5 µA).
Components highlighted in yellow are populated at the factory. Components highlighted in gray are optional.
Inertial sensors have a dedicated SPI bus interface (SPI1). This SPI supports a faster communication speed (up
to 10 Mbps) with respect to the I²C. Inertial sensors can generate data at a high output data rate (up to 6.6k
samples per second) and require a fast interface. The following pins are also connected:
• HIGH_G_CS, ACC_CS, and IMU_CS chip select: needed by the SPI interface respectively to select
the high-g accelerometer H3LIS331DL, the low-power accelerometer LIS2DUXS12, or the smart IMU
LSM6DSO32X
• HIGH_G_INT1, ACC_INT1, and ACC_INT2 interrupt line from the
two interrupt lines from both
Note: HIGH_G_INT1 (PA2) and USER (PB2) are mutually exclusive and cannot be used at the same time with
the EXTI peripheral (external interrupt handler on the MCU).
ACC_INT1 (PA0) e ACC_INT2 (PB0) are mutually exclusive and cannot be used at the same time with the
EXTI peripheral (external interrupt handler on the MCU).
Note: When the microcontroller supplies power to other components in the system, follow specific sequences
to enable/disable the SPI interface and use the CS chip select. Incorrect sequences can allow power to
flow from the communication bus to the components, through the protection diodes, compromising their
operation.
Ambient and environmental sensors have a dedicated I²C bus interface (I2C1). Optionally, each environmental
sensor (except the ambient light sensor) can be rerouted to the LSM6DSO32X, which is the sensor hub. The
following pins are also connected:
UM3034 - Rev 1
NFC/EEPROM has a dedicated I²C bus interface (I2C3). The following pins are also connected:
Figure 4. STEVAL-SMARTAG2 architecture and communication paths
LIS2DUXS12
ST25DV64KC
H3LIS331DL
and LSM6DSO32X in the wired-OR configuration.
UM3034
System architecture
must be put in standby in its
high-g accelerometer, and
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