Hi Folks
Problem: Arduino Nano IOT 33 does not forward commands (from IDE Serial window) to the Atlas Scientific Probe via I2C
I have done some debugging:
- checked I2C connection between UNO & IOT33 - working well
- ran the Atlas Scientific code on UNO (with the probe attached)- working very well
- checked all the wiring & hardware - no issues (run on 3.3Volts obviously)
so, why does this not work with the IOT33?
- I downloaded an example SerialEvent sketch on IDE - not working.
therefore I am assuming that the serial communication between the Arduino IDE and IOT 33 is not working - preventing the commands to get to the probe.
Do I have to do something with SERCOM5? I don't understand it.
could you please help me with this.
pls find the sketches below:
Atlas Scientific Sample code:
//This code was written to be easy to understand.
//Modify this code as you see fit.
//This code will output data to the Arduino serial monitor.
//Type commands into the Arduino serial monitor to control the EZO D.O. Circuit.
//This code was written in the Arduino 1.8.9 IDE
//This code was last tested 7/2019
#include <Wire.h> //enable I2C.
#define address 97 //default I2C ID number for EZO DO Circuit.
char computerdata[20]; //we make a 20 byte character array to hold incoming data from a pc/mac/other.
byte received_from_computer = 0; //we need to know how many characters have been received.
byte serial_event = 0; //a flag to signal when data has been received from the pc/mac/other.
byte code = 0; //used to hold the I2C response code.
char do_data[20]; //we make a 20 byte character array to hold incoming data from the D.O. circuit.
byte in_char = 0; //used as a 1 byte buffer to store inbound bytes from the D.O. Circuit.
byte i = 0; //counter used for DO_data array.
int time_ = 575; //used to change the delay needed depending on the command sent to the EZO Class DO Circuit.
char *DO; //char pointer used in string parsing.
char *sat; //char pointer used in string parsing.
float DO_float; //float var used to hold the float value of the D.O.
float sat_float; //float var used to hold the float value of the percent saturation.
void setup() //hardware initialization.
{
Serial.begin(9600); //enable serial port.
Wire.begin(); //enable I2C port.
}
void serialEvent() { //this interrupt will trigger when the data coming from the serial monitor(pc/mac/other) is received.
received_from_computer = Serial.readBytesUntil(13, computerdata, 20); //we read the data sent from the serial monitor(pc/mac/other) until we see a <CR>. We also count how many characters have been received.
computerdata[received_from_computer] = 0; //stop the buffer from transmitting leftovers or garbage.
serial_event = true; //set the serial event flag.
}
void loop() { //the main loop.
if (serial_event == true) { //if a command was sent to the EZO device.
for (i = 0; i <= received_from_computer; i++) { //set all char to lower case, this is just so this exact sample code can recognize the "sleep" command.
computerdata[i] = tolower(computerdata[i]); //"Sleep" ≠ "sleep"
}
i=0; //reset i, we will need it later
if (computerdata[0] == 'c' || computerdata[0] == 'r')time_ = 575; //if a command has been sent to calibrate or take a reading we wait 575ms so that the circuit has time to take the reading.
else time_ = 250; //if any other command has been sent we wait only 250ms.
Wire.beginTransmission(address); //call the circuit by its ID number.
Wire.write(computerdata); //transmit the command that was sent through the serial port.
Wire.endTransmission(); //end the I2C data transmission.
if (strcmp(computerdata, "sleep") != 0) { //if the command that has been sent is NOT the sleep command, wait the correct amount of time and request data.
//if it is the sleep command, we do nothing. Issuing a sleep command and then requesting data will wake the D.O. circuit.
delay(time_); //wait the correct amount of time for the circuit to complete its instruction.
Wire.requestFrom(address, 20, 1); //call the circuit and request 20 bytes (this is more than we need)
code = Wire.read(); //the first byte is the response code, we read this separately.
switch (code) { //switch case based on what the response code is.
case 1: //decimal 1.
Serial.println("Success"); //means the command was successful.
break; //exits the switch case.
case 2: //decimal 2.
Serial.println("Failed"); //means the command has failed.
break; //exits the switch case.
case 254: //decimal 254.
Serial.println("Pending"); //means the command has not yet been finished calculating.
break; //exits the switch case.
case 255: //decimal 255.
Serial.println("No Data"); //means there is no further data to send.
break; //exits the switch case.
}
while (Wire.available()) { //are there bytes to receive.
in_char = Wire.read(); //receive a byte.
do_data[i] = in_char; //load this byte into our array.
i += 1; //incur the counter for the array element.
if (in_char == 0) { //if we see that we have been sent a null command.
i = 0; //reset the counter i to 0.
break; //exit the while loop.
}
}
Serial.println(do_data); //print the data.
Serial.println(); //this just makes the output easier to read by adding an extra blank line
}
serial_event = false; //reset the serial event flag.
//if (computerdata[0] == 'r') string_pars(); //uncomment this function if you would like to break up the comma separated string into its individual parts.
}
}
void string_pars() { //this function will break up the CSV string into its 2 individual parts. DO|SAT|
//this is done using the C command “strtok”.
DO = strtok(do_data, ","); //let's pars the string at each comma.
sat = strtok(NULL, ","); //let's pars the string at each comma.
Serial.print("DO:"); //we now print each value we parsed separately.
Serial.println(DO); //this is the D.O. value.
Serial.print("SAT:"); //we now print each value we parsed separately.
Serial.println(sat); //this is the percent saturation.
Serial.println(); //this just makes the output easier to read by adding an extra blank line
//uncomment this section if you want to take the values and convert them into floating point number.
/*
DO_float=atof(DO);
sat_float=atof(sat);
*/
}
I have spent some time this morning finding other examples but I still don't understand, how to replace serialEvent. What is the alternative solution for SAMD boards?