Demo sketch esp8266->I2C>Arduino
Posted: Thu Sep 17, 2015 11:22 amHi,
I have been trying to make ESP-01 talk to an Arduino via I2C, and it is almost succesfull.
The reason why this could be a good idea is that you get 6 analog inputs and a lot of digital pin's
In this webserver there are two functions.
One toggles the Led on pin 13 and the other reads the analog value on A1.
It works almost, but for some reason if you click the pin toogle you get the analog value, but only the first time.
The next click gives the right value.
Maybe someone can see the error ?
Edit:
And this is the sketch for the slave running on a 3.3V Arduino
I have been trying to make ESP-01 talk to an Arduino via I2C, and it is almost succesfull.
The reason why this could be a good idea is that you get 6 analog inputs and a lot of digital pin's
In this webserver there are two functions.
One toggles the Led on pin 13 and the other reads the analog value on A1.
It works almost, but for some reason if you click the pin toogle you get the analog value, but only the first time.
The next click gives the right value.
Maybe someone can see the error ?
Code: Select all
//I2c code from: http://www.berryjam.eu/2014/07/advanced-arduino-i2c-communication/
// (c) 2014 Ignas Gramba
#include <ESP8266WiFi.h>
#include <ESP8266WebServer.h>
#include <Wire.h>
ESP8266WebServer webserver(80);
#define SlaveDeviceId 9
int value;
int pinValue;
void handleRoot() {
String arg0 = String(webserver.arg(0));
String arg1 = String(webserver.arg(1));
if (webserver.arg(0) == "1") {
pinValue = setPin(); // slave toggles led
}
if (webserver.arg(0) == "2") {
value = getValue(); // slave reads analog
}
String val = String(value);
String pin = String(pinValue);
String htmlDoc = "<!DOCTYPE html>";
htmlDoc += "<html>";
htmlDoc += "<head>";
htmlDoc += "<title>TWI . Demo</title>";
htmlDoc += "</head>";
htmlDoc += "<body>";
htmlDoc += "<br>Toggle led <a href='/?led=1'>click</a><br>";
htmlDoc += "<br>Raed analog value <a href='/?led=2'>click</a><br>";
htmlDoc += "<br>";
htmlDoc += "pinStatus=" + pin + " Analog value=" + val;
htmlDoc += "<br>";
htmlDoc += "</body>";
htmlDoc += "</html>";
webserver.send(200, "text/html", htmlDoc);
}
void handleNotFound() {
webserver.send(404, "text/plain", "Page not found ...");
}
void setup() {
Serial.begin(115200);
Wire.begin(0, 2); // join i2c bus sda,scl
delay(10);
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}
Serial.println("");
Serial.println("WiFi connected");
WiFi.begin("xxx", "yyyyy");
delay(100);
webserver.on("/", handleRoot);
webserver.onNotFound(handleNotFound);
webserver.begin();
Serial.println("Web server has started on: ");
Serial.print(WiFi.localIP());
}
void loop() {
webserver.handleClient();
}
int setPin() {
Wire.beginTransmission(SlaveDeviceId);
Wire.write(8); // Transfer command ("8") to set pin command
delay(100);
// GET RESPONSE
int receivedValue = 0;
Wire.requestFrom(SlaveDeviceId, 2);
receivedValue = Wire.read() << 8 | Wire.read(); // combine two bytes into integer
int error = Wire.endTransmission();
Serial.println(error);
// Serial.print(" Setpin= ");
// Serial.println(receivedValue);
return receivedValue;
}
int getValue() {
Wire.beginTransmission(SlaveDeviceId);
Wire.write(1); // Transfer command ("1") to get X sensor value;
delay(100);
// GET RESPONSE
int receivedValue1 = 0;
Wire.requestFrom(SlaveDeviceId, 2);
receivedValue1 = Wire.read() << 8 | Wire.read(); // combine two bytes into integer
int error = Wire.endTransmission();
//Serial.println(error);
// Serial.print(" Analog= ");
// Serial.println(receivedValue1);
return receivedValue1;
}
Edit:
And this is the sketch for the slave running on a 3.3V Arduino
Code: Select all
//http://www.berryjam.eu/2014/07/advanced-arduino-i2c-communication/
// (c) 2014 Ignas Gramba
//
#include <Wire.h>
#define SensorPin 1
#define ledPin 13
const byte SlaveDeviceId = 9;
byte LastMasterCommand = 0;
byte state = 0;
void setup() {
//Serial.begin(115200);
Wire.begin(SlaveDeviceId); // join i2c bus with Slave ID
Wire.onReceive(receiveCommand); // register talk event
Wire.onRequest(slavesRespond); // register callback event
pinMode(SensorPin, INPUT);
pinMode(ledPin, OUTPUT);
}
void loop() {
delay(100);
}
void receiveCommand(int howMany) {
LastMasterCommand = Wire.read(); // 1 byte (maximum 256 commands)
}
void slavesRespond() {
int returnValue = 0;
switch (LastMasterCommand) {
case 0: // No new command was received
Wire.write("NA");
break;
case 1: // Return X sensor value
returnValue = GetXSensorValue();
break;
case 8: // Return Y sensor value
returnValue = setPin();
break;
}
byte buffer[2];
buffer[0] = returnValue >> 8;
buffer[1] = returnValue & 255;
Wire.write(buffer, 2);
LastMasterCommand = 0; // null last Master's command
}
int GetXSensorValue() {
int val = analogRead(SensorPin);
//int val = analogRead(SensorPin);
return val;
}
int setPin() {
state = !state;
digitalWrite(ledPin, state);
return state;
}