DocID025832 Rev 2
STM32F042xx
Functional overview
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from the CPU clock, allowing the I2C1 to wake up the MCU from Stop mode on address
match.
The I2C interface can be served by the DMA controller.
3.15
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. USART1 supports also SmartCard communication (ISO
7816), IrDA SIR ENDEC, LIN Master/Slave capability and auto baud rate feature, and has a
clock domain independent from the CPU clock, allowing USART1 to wake up the MCU from
Stop mode.
The USART interfaces can be served by the DMA controller.
for the differences between USART1 and USART2.
Table 9. STM32F042x I
2
C implementation
I2C features
(1)
1. X = supported.
I2C1
7-bit addressing mode
X
10-bit addressing mode
X
Standard mode (up to 100 kbit/s)
X
Fast mode (up to 400 kbit/s)
X
Fast Mode Plus with 20mA output drive I/Os (up to 1 Mbit/s)
X
Independent clock
X
SMBus
X
Wakeup from STOP
X
Table 10. STM32F042x USART implementation
USART modes/features
(1)
USART1
USART2
Hardware flow control for modem
X
X
Continuous communication using DMA
X
X
Multiprocessor communication
X
X
Synchronous mode
X
X
Smartcard mode
X
(2)
Single-wire half-duplex communication
X
X
IrDA SIR ENDEC block
X