adafruit-mirror/arduino-esp32
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

Added example to demonstrate using HardwareSerial with RS485 interfaces (#8941)

Browse source 
* Added Serial as RS485 interface demo

* Added more detail to initial comment

* Switched to UART_MODE definitions from uart_types.h in order to accomodate some versions of Arduino core

* Update libraries/ESP32/examples/Serial/RS485_Echo_Demo/RS485_Echo_Demo.ino

Co-authored-by: Lucas Saavedra Vaz <lucassvaz@yahoo.com.br>

* Update libraries/ESP32/examples/Serial/RS485_Echo_Demo/RS485_Echo_Demo.ino

Co-authored-by: Lucas Saavedra Vaz <lucassvaz@yahoo.com.br>

* Update libraries/ESP32/examples/Serial/RS485_Echo_Demo/RS485_Echo_Demo.ino

Co-authored-by: Lucas Saavedra Vaz <lucassvaz@yahoo.com.br>

* Removed HardwareSerial.h include. Switched RTS pin to GPIO 4 for broader compatability.

* using 115200 for UART0 - console

---------

Co-authored-by: Lucas Saavedra Vaz <lucassvaz@yahoo.com.br>
Co-authored-by: Rodrigo Garcia <rodrigo.garcia@espressif.com>
This commit is contained in:
Neale Petrillo 2023-12-20 09:35:31 -05:00 committed by GitHub
parent 5d97e02ad7
commit 812a59aadd
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
1 changed files with 48 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

48
libraries/ESP32/examples/Serial/RS485_Echo_Demo/RS485_Echo_Demo.ino Normal file
View file

@ -0,0 +1,48 @@
/*
This Sketch demonstrates how to use the Hardware Serial peripheral to communicate over an RS485 bus.
Data received on the primary serial port is relayed to the bus acting as an RS485 interface and vice versa.
UART to RS485 translation hardware (e.g., MAX485, MAX33046E, ADM483) is assumed to be configured in half-duplex
mode with collision detection as described in
https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/peripherals/uart.html#circuit-a-collision-detection-circuit
To use the script open the Arduino serial monitor (or alternative serial monitor on the Arduino port). Then,
using an RS485 tranciver, connect another serial monitor to the RS485 port. Entering data on one terminal
should be displayed on the other terminal.
*/
#include "hal/uart_types.h"
#define RS485_RX_PIN 16
#define RS485_TX_PIN 5
#define RS485_RTS_PIN 4
#define RS485 Serial1
void setup() {
Serial.begin(115200);
while(!Serial) { delay(10); }
RS485.begin(9600, SERIAL_8N1, RS485_RX_PIN, RS485_TX_PIN);
while(!RS485) { delay(10); }
if(!RS485.setPins(-1, -1, -1, RS485_RTS_PIN)){
Serial.print("Failed to set RS485 pins");
}
// Certain versions of Arduino core don't define MODE_RS485_HALF_DUPLEX and so fail to compile.
// By using UART_MODE_RS485_HALF_DUPLEX defined in hal/uart_types.h we work around this problem.
// If using a newer IDF and Arduino core you can ommit including hal/uart_types.h and use MODE_RS485_HALF_DUPLEX
// defined in esp32-hal-uart.h (included during other build steps) instead.
if(!RS485.setMode(UART_MODE_RS485_HALF_DUPLEX)) {
Serial.print("Failed to set RS485 mode");
}
}
void loop() {
if (RS485.available()) {
Serial.write(RS485.read());
}
if (Serial.available()) {
RS485.write(Serial.read());
}
}