AN4457 Datasheet, PDF (1/24 Pages) STMicroelectronics – Implementing an emulated universal asynchronous receiver transmitter on STM32F4 microcontroller series

AN4457
Application note
Implementing an emulated universal asynchronous receiver
transmitter on STM32F4 microcontroller series
Introduction
This application note describes how to implement an emulated universal asynchronous
receiver transmitter (UART) on STM32F4 series.
Such an emulator is needed in applications that require more UARTs than the ones provided
by STM32F4 microcontrollers.
The emulated UART is full-duplex, supports up to 9 data bits and baud rates up to
115200 bps. It also offers a high flexibility since any I/O pin can be used as TX or RX line. In
addition, this UART emulation uses the DMA to minimize CPU usage.
This application note provides a basic example of communications between a hardware and
a software UART as well as a summary of CPU load and firmware footprint.
The STSW-STM32156 firmware package is delivered with this document and contains the
source code of the UART emulator with all firmware modules required to run the example.
Type
Microcontrollers
Embedded software
Table 1. Applicable products
Part numbers
STM32F4 series
STSW-STM32156
March 2015
DocID026046 Rev 1
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