Datasheet

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STM32L011x3/4 Functional overview
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3.15.3 Low-power universal asynchronous receiver transmitter (LPUART)
The devices embed one Low-power UART. The LPUART supports asynchronous serial
communication with minimum power consumption. It supports half duplex single wire
communication and modem operations (CTS/RTS). It allows multiprocessor
communication.
The LPUART has a clock domain independent from the CPU clock, and can wake up the
system from Stop mode, using baudrates up to 46 Kbaud. The Wakeup events from Stop
mode are programmable and can be:
• Start bit detection
• Or any received data frame
• Or a specific programmed data frame
Only a 32.768 kHz clock (LSE) is needed to allow LPUART communication up to 9600
baud. Therefore, even in Stop mode, the LPUART can wait for an incoming frame while
having an extremely low energy consumption. Higher speed clock can be used to reach
higher baudrates.
LPUART interface can be served by the DMA controller.
3.15.4 Serial peripheral interface (SPI)
The SPI is able to communicate at up to 16 Mbits/s in slave and master modes in full-duplex
and half-duplex communication modes. The 3-bit prescaler gives 8 master mode
frequencies and the frame is configurable to 8 bits or 16 bits. The hardware CRC
generation/verification supports basic SD Card/MMC modes.
The SPI can be served by the DMA controller.
Refer to Table 11 for the supported modes and features of SPI interface.
3.16 Cyclic redundancy check (CRC) calculation unit
The CRC (cyclic redundancy check) calculation unit is used to get a CRC code using a
configurable generator polynomial value and size.
Among other applications, CRC-based techniques are used to verify data transmission or
storage integrity. In the scope of the EN/IEC 60335-1 standard, they offer a means of
verifying the Flash memory integrity. The CRC calculation unit helps compute a signature of
the software during runtime, to be compared with a reference signature generated at
linktime and stored at a given memory location.
Table 11. SPI implementation
SPI features
(1)
1. X = supported.
SPI1
Hardware CRC calculation X
I2S mode -
TI mode X
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