General Information

I tried to build a fluent API for communication with GSM modems in a generic and efficient way.
There are plenty of GSM modem clients out there but very few of them are truthly asynchronous and others just using delay() in their code which can cause problems in other parts of process.

Anyway technically this code run on any boards which can run Arduino framework but I did tested it only on esp8266.

Quickstart

Let's say we want to test if our modem is up and running and if AT Echo is enabled, We turn it off.
In this example I used SoftwareSerial on D3 & D4 pins but you are free to use HardwareSerial or even a Tcp stream!

#include <Arduino.h>
#include <SoftwareSerial.h>
#include <ATConnection.hpp>

SoftwareSerial swSerial(D3, D4);
ATConnection at(&swSerial);

void setup() {
    Serial.begin(9600);
    swSerial.begin(9600);
    delay(1000);

    // Setup event listener
    at.on(ATNotificationEvent::type, [](const Event *env) {
        auto notification = (const ATNotificationEvent *)env;
        Serial.printf("AT Notfication: \"%s\"\n", notification->content.c_str());
    });

    Serial.println("checking the connection:");
    at.execute("AT")
        ->onSuccess([](const String &result) {
            bool echo = result.startsWith("AT");
            Serial.print("Modem successfully respond and AT Echo is ");
            Serial.println(echo ? "on, i'm going to turn it off!" : "off.");
            if (echo) {
                at.execute("ATE0")->freeOnFinish();
            }
        })
        ->onFail([](const std::exception &e) {
            Serial.printf("Modem respond with error");
        })
        ->freeOnFinish();
}

void loop() {
    at.communicate();
}

You can build and upload this code to your board quickly with Ready-To-Use Example

Important to Remember

Currently the library using heap memory to construct promises so you must take care of free the memory of promise.
Dont forget that deleting a promise before it's finished can cause undefined behavior.
There is a void Promise<T>::freeOnFinish() method can certainly help you with this matter.

Methods & Helpers

ATConnection::ATConnection(Stream *stream):
The connection constructor needs a stream, It's usully is a Software or Hardware serial but technically it even can be a TCP stream!

Promise\<void> *ATConnection::setValue(char *variable, char *value, uint8_t timeuot = 2):
It's basically an alias for ATConnection::execute("AT+${variable}=${value}", timeuot).

Promise\<String> *ATConnection::getValue(char *variable, uint8_t timeuot = 2):
It's basically an alias for ATConnection::execute("AT+${variable}?", timeuot).

Promise\<String> *ATConnection::test(char *variable, uint8_t timeuot = 2):
It's basically an alias for ATConnection::execute("AT+${variable}=?", timeuot).

Promise\<String> *ATConnection::execute(char *command, uint8_t timeuot = 2):
Sends command to the modem and waits for it's response.
If the response ends with "OK" promise will resolve with any data after sending the command and receive the OK.
If the response ends with "ERROR" promise will reject any data after sending the command and receive the ERROR.

Promise\<String> *ATConnection::execute(char *command, char *secondPart, uint8_t timeuot = 20):
It's like prevouis form but if there is a need to send second part of payload, it will send it.
Executing commands like AT+CMGS needs this form.

void ATConnection::communicate():
Read from / Write to stream. You should put it in loop() method.

Time Limit

Every method of this library that run a AT command has a default timeout for that command of 2 seconds.

Except for two-part-execute (command, secondPart, timeuot) method which has a 20 seconds time. This method usually used for sending sms and other time-consuming tasks.

If you want to disable the timeout set it to 0.

TODO

Unit tests.

License

The library is licensed under MIT

yeganemehr / arduino-at

readme