Menu
ReferenceLanguage | Libraries | Comparison | Changes
The newer version of 1Sheeld (1Sheeld+) built to support both iOS and Android devices,but not just that! There’s another secret feature supported to solve the problem of using extra shield/board over 1Sheeld+, and this shield/board have the same way of communication used by 1Sheeld+ (The hardware UART serial pins pin0&pin1) with your Arduino. You stumbled upon the difference between hardware serial / UART and serial emulated in software. Hardware serial. The following pins support hardware serial / UART. It implies little processor overhead as the hardware takes care of the tough work. To use the software serial port, first the header file for the software serial library must be included. #include Next create the software serial port, selecting the Arduino pins to use for receive (RX) and transmit (TX). Here pin 8 has been set as the receive pin and pin 7 as the transmit pin. SoftwareSerial gtSerial(8, 7).
Arduino Software Serial Pins For Free
SoftwareSerial Library
The Arduino hardware has built-in support for serial communication on pins 0 and 1 (which also goes to the computer via the USB connection). The native serial support happens via a piece of hardware (built into the chip) called a UART. This hardware allows the Atmega chip to receive serial communication even while working on other tasks, as long as there room in the 64 byte serial buffer. The SoftwareSerial library has been developed to allow serial communication on other digital pins of the Arduino, using software to replicate the functionality (hence the name 'SoftwareSerial'). It is possible to have multiple software serial ports with speeds up to 115200 bps. A parameter enables inverted signaling for devices which require that protocol. The version of SoftwareSerial included in 1.0 and later is based on the NewSoftSerial library by Mikal Hart. LimitationsThe library has the following known limitations:
If your project requires simultaneous data flows, see Paul Stoffregen's AltSoftSerial library. AltSoftSerial overcomes a number of other issues with the core SoftwareSerial, but has it's own limitations. Refer to the AltSoftSerial site for more information. Examples
| Functions
|
Corrections, suggestions, and new documentation should be posted to the Forum.
The text of the Arduino reference is licensed under aCreative Commons Attribution-ShareAlike 3.0 License. Code samples in the reference are released into the public domain.
Active12 months ago
I am communicating with ESP8266 using SoftwareSerial of Arduino UNO. I can successfully send AT commands and get response when communicating through the terminal. But if i programmatically send particular AT commands there is no response. For eg: I type AT in serial monitor I get OKBut if i send the following through SoftwareSerial pins
there is no response.
Can anyone tell what will be the solution as to how to send AT commands explicitly.
The sketch is
I am using Sparkfun Level Shifter to get 3.3V from 5V. The wiring is straightforward. ESP8266 Vcc and CH_PD to 3.3V; GND to GND; Tx to Arduino 2(Rx) directly; Rx to Sparkfun 3.3V RXO LV side and Arduino 3(Tx) to RXI HV side) so that when Arduino transmits it gets stepped down to 3.3V and ESP8266 receives it. The wiring should be correct as it is working perfectly when AT commands are sent manually.
I tried everything of sending mySerial.write('AT/r/n'), mySerial.print('AT') mySerial.print('rn'), etc but nothing seems to work.
Is it that there is some problem with SoftwareSerial. But then how is it working if i send AT commands manually through terminal ?
Igor Stoppa1,99911 gold badge77 silver badges2020 bronze badges
Dave127Dave127
Free Software Serial No
5 Answers
I have been playing with an ESP8266 over the last couple of days with similar results. My conclusion was that it is very timing dependent.
If you build in (fairly large) delays into your code then you will find it works better. The delays are effectively what you are doing as you type in each new command.
I found, for example, that the
AT+CWJAP
(join access point) command takes quite a while, like 10 seconds or so. Preferably don't use 'actual' delays because they are blocking (unless you don't care about that). You could have a list of commands you want to send, and a system that pulls the next one out of the list when a certain time has elapsed.
If you use something like 5 to 10 second delays between commands you should get better results. At the very least, after sending one command, look for a confirmation string from the device (eg.
Nick Gammon♦Nick GammonOK
, ERROR
etc.).29.3k88 gold badges4949 silver badges104104 bronze badges
Same problem here with this code.
Three step for me to make it work :
- Use method write() and not println()
- Send newline n when talking to esp8266
- don't wait newline to print the response
I hope it helps
MabdylonMabdylon
It appears to me that when the ESP8266 sends a few characters to the Arduino, the initial version of the code always erases those characters (
data=';
) without ever printing anything to your serial monitor.So there is no way to tell whether the ESP8266 is sending anything or not.To make it easier to debug, try printing every character from the ESP8266 to the serial monitor, whether or not it makes a complete message.
What do you see on the serial monitor with the following code?
David CaryDavid Cary
![Arduino Software Serial Pins Arduino Software Serial Pins](/uploads/1/2/6/4/126468754/417571989.jpg)
Did you make sure that your lines end with nr?
Remember you need both newline characters to send over the line from the terminal.
Hyra PowerHyra Power
Arduino Mega 2560 Software Serial Pins
The ESP8266 needs 115200 baud.
The example didn't run clean in my case until I increased the baud rate for the Arduino<->Computer (USB) communication to 115200 baud as well. With 115200 on mySerial and 9600 on USB, an AT request of mine did not return an OK in most cases.
user49924user49924