STM32L021D4 datasheet(32/114 Pages) STMICROELECTRONICS

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Functional overview

STM32L021x4

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DocID027982 Rev 5

3.16.4

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 10 for the supported modes and features of SPI interface.

3.17

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.

3.18

Serial wire debug port (SW-DP)

An Arm SW-DP interface is provided to allow a serial wire debugging tool to be connected to

the MCU.

Table 10. SPI implementation

SPI features(1)

1. X = supported.

SPI1

Hardware CRC calculation

I2S mode

TI mode

STM32L021D4 Datenblatt(PDF) 32 Page - STMicroelectronics