STM32F051K8U6 Datasheet, PDF (24/104 Pages) STMicroelectronics – Low- and medium-density advanced ARM™-based 32-bit MCU with 16 to 64 Kbytes Flash, timers, ADC, DAC and comm. interfaces

Functional overview
STM32F051x
3.17
Universal synchronous/asynchronous receiver transmitters
(USART)
The device embeds up to two universal synchronous/asynchronous receiver transmitters
(USART1 and USART2), which communicate at speeds of up to 6 Mbit/s.
They provide hardware management of the CTS, RTS and RS485 DE signals,
multiprocessor communication mode, master synchronous communication and single-wire
half-duplex communication mode. The USART1 supports also SmartCard communication
(ISO 7816), IrDA SIR ENDEC, LIN Master/Slave capability, auto baud rate feature and has a
clock domain independent from the CPU clock, allowing the USART1 to wake up the MCU
from Stop mode.
The USART interfaces can be served by the DMA controller.
Refer to Table 10 for the differences between USART1 and USART2.
Table 10. STM32F051x USART implementation
USART modes/features⁽¹⁾
Hardware flow control for modem
Continuous communication using DMA
Multiprocessor communication
Synchronous mode
Smartcard mode
Single-wire half-duplex communication
IrDA SIR ENDEC block
LIN mode
Dual clock domain and wakeup from Stop mode
Receiver timeout interrupt
Modbus communication
Auto baud rate detection
Driver Enable
1. X = supported.
USART1
X
X
X
X
X
X
X
X
X
X
X
X
X
USART2
X
X
X
X
X
X
3.18
Serial peripheral interface (SPI)/Inter-integrated sound
interfaces (I²S)
Up to two SPIs are able to communicate up to 18 Mbits/s in slave and master modes in full-
duplex and simplex communication modes. The 3-bit prescaler gives 8 master mode
frequencies and the frame size is configurable from 4 bits to 16 bits.
One standard I²S interface (multiplexed with SPI1) supporting four different audio standards
can operate as master or slave at simplex communication mode. It can be configured to
transfer 16 and 24 or 32 bits with16-bit or 32-bit data resolution and synchronized by a
specific signal. Audio sampling frequency from 8 kHz up to 192 kHz can be set by 8-bit
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Doc ID 022265 Rev 3