STM32F042F4 datasheet(27/117 Pages) STMICROELECTRONICS

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STM32F042x4 STM32F042x6

Functional overview

with 29-bit identifiers. It has three transmit mailboxes, two receive FIFOs with 3 stages and

14 scalable filter banks.

3.19

Universal serial bus (USB)

The STM32F042x4/x6 embeds a full-speed USB device peripheral compliant with the USB

specification version 2.0. The internal USB PHY supports USB FS signaling, embedded DP

pull-up and also battery charging detection according to Battery Charging Specification

Revision 1.2. The USB interface implements a full-speed (12 Mbit/s) function interface with

added support for USB 2.0 Link Power Management. It has software-configurable endpoint

setting with packet memory up-to 1 KB (the last 256 byte are used for CAN peripheral if

enabled) and suspend/resume support. It requires a precise 48 MHz clock which can be

generated from the internal main PLL (the clock source must use an HSE crystal oscillator)

or by the internal 48 MHz oscillator in automatic trimming mode. The synchronization for this

oscillator can be taken from the USB data stream itself (SOF signalization) which allows

crystal-less operation.

3.20

Clock recovery system (CRS)

The STM32F042x4/x6 embeds a special block which allows automatic trimming of the

internal 48 MHz oscillator to guarantee its optimal accuracy over the whole device

operational range. This automatic trimming is based on the external synchronization signal,

which could be either derived from USB SOF signalization, from LSE oscillator, from an

external signal on CRS_SYNC pin or generated by user software. For faster lock-in during

startup it is also possible to combine automatic trimming with manual trimming action.

3.21

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.

STM32F042F4 датащи(PDF) 27 Page - STMicroelectronics