AN3070 Datasheet, PDF (1/12 Pages) STMicroelectronics – Managing the Driver Enable signal for RS-485 and IO-Link

AN3070
Application note
Managing the Driver Enable signal for RS-485 and IO-Link
communications with the STM32™’s USART
Introduction
RS-485 and IO-Link are half-duplex communication protocols that offer easy ways of
implementing the physical layer in industrial networks.
The STM32F10x, which comes with up to 5 UART interfaces and features fast DMA transfer
and low interrupt latency, meets the RS-485 and IO-Link timing specifications.
This application note aims at providing timing measurements of the DE signal (Driver
Enable) switching by using two different methods for managing this signal in RS-485 and
IO-Link master transmission.
The application note is organized into three parts:
● it first explains why the timing of the DE signal is critical
● it then describes the two methods used to manage the DE signal
● and, finally, it gives different measurements of the DE signal switching time
January 2010
Doc ID 16312 Rev 1
1/12
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