STM32L151XE datasheet(30/134 Pages) STMICROELECTRONICS

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Functional overview

STM32L151xE STM32L152xE

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DocID025433 Rev 8

3.17.3

Serial peripheral interface (SPI)

Up to three SPIs are 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 SPIs can be served by the DMA controller.

3.17.4

Inter-integrated sound (I2S)

Two standard I2S interfaces (multiplexed with SPI2 and SPI3) are available. They can

operate in master or slave mode, and can be configured to operate with a 16-/32-bit

resolution as input or output channels. Audio sampling frequencies from 8 kHz up to 192

kHz are supported. When either or both of the I2S interfaces is/are configured in master

mode, the master clock can be output to the external DAC/CODEC at 256 times the

sampling frequency.

The I2Ss can be served by the DMA controller.

3.17.5

Universal serial bus (USB)

The STM32L151xE and STM32L152xE devices embed a USB device peripheral compatible

with the USB full-speed 12 Mbit/s. The USB interface implements a full-speed (12 Mbit/s)

function interface. It has software-configurable endpoint setting and supports

suspend/resume. The dedicated 48 MHz clock is generated from the internal main PLL (the

clock source must use a HSE crystal oscillator).

3.18

CRC (cyclic redundancy check) calculation unit

The CRC (cyclic redundancy check) calculation unit is used to get a CRC code from a 32-bit

data word and a fixed generator polynomial.

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 link-

time and stored at a given memory location.

STM32L151XE Datasheet(PDF) 30 Page - STMicroelectronics