yun shield compatibilty question- DFRobot Forum

2014-03-19 00:53:45 Piero,

You are right, the pins are connected directly to the bridge :(

You can try to bend a little the Rx Tx pins on the shield so they are not plugged in, and using some male to male wires, plug them from Rx Tx to some other pins. Jose

2014-03-18 00:27:58 Hi Grey,
I found on the Arduino's support that the pins TX and RX practically can not be used because they are already used by the Bridge through the class Serial1 for communication between 32u4 and AR9331. So one solution would be to use the SoftwareSerial library ([url=http://arduino.cc/en/Reference/SoftwareSerial]http://arduino.cc/en/Reference/SoftwareSerial[/url]) and connect the pins of the serial communication on other pins (preferably from 8 to up, since since these support change interrupts) ....
later I will test this solution ....
I hope everything is ok
Piero76

2014-03-15 02:42:03 It is very strange.
Could you connect RS485 GND port together?
Grey.CC

2014-03-15 01:04:07 Hi Grey,

I used separately Serial class and Serial1 class.

In fact, I connected in parallel to rs485 this device :

[img]http://i00.i.aliimg.com/wsphoto/v0/834970564/Free-Shipping-font-b-USB-b-font-to-font-b-RS485-b-font-485-Converter-Adapter.jpg[/img]

An USB to rs485 converter

And so I can read the packets via sniffing Serial COM softwares like Hercules or Putty or others..........
But, while i can read on the Yun's COM the "A" letter, if I select the Adapter's COM ( which theoretically should intercept all packets that pass through the rs485) I read only FF packets (noises ??).

This method works fine with Arduino Uno.
Piero76

2014-03-14 18:41:20 Hey,
For your sample code.
There is no communication between Serial and Serial1
I guess you need some code like this
[code]
if(Serial1.available()>0)
{
char inbyte=Serial1.read();
Serial.print(inbyte);
}[/code]

Your PC is using Serial to communicate with YUN, it can'r receive any data from Serial1.
So you need to print what Serial1 received to Serial.
Grey.CC

2014-03-14 01:58:03 I used first tue example code from the shield's wiki doc to test it (appropriately modified) , first on the arduino uno (the original code) and then on the yun (the modified code), and while the first works well ( I can see trough my rs485-usb interface for pc the letter A), with the yun I just can see only FF packets ( that I think they are only noises)

Anyway this is the modified sample code that I used

[quote]

#include <Bridge.h>
#include <Console.h>
#include <FileIO.h>
#include <HttpClient.h>
#include <Mailbox.h>
#include <Process.h>
#include <YunClient.h>
#include <YunServer.h>

int EN = 2; //RS485 has a enable/disable pin to transmit or receive data. Arduino Digital Pin 2 = Rx/Tx 'Enable'; High to Transmit, Low to Receive

void setup()
{
pinMode(EN, OUTPUT);
Serial1.begin(9600);
Serial.begin(9600);
}

void loop()
{
// send data
digitalWrite(EN, HIGH);//Enable data transmit
Serial1.print('A');
Serial.print('A');
delay(1000);
}[/quote]
I use the Serial class for the serial monitor (otherwise I wouldn't see anything on the monitoring program) and the Serial1 class to use the rs485 interface on the shield.

is that correct ?

Maybe I should cut any pin to avoid conflicts ? Piero76

2014-03-14 01:24:38 Exactly,
The MCU chip is 32u4, it use dfrobot&TX1 to replace the RX0&TX0, like Leonardo.
You need change some "Serial" to "Serial1"
Serial1 will receive the RS485 signal.
Do you have an oscilloscope or a logic analyzer?
Could you attach your code?

Grey.CC

2014-03-14 00:28:43 Hello Grey,
Thanks for your reply,
Yes, I move the three jumpers to select the rs485.
After reading a lot of the documentation regard the Yun, I understand that this arduino, like the arduino Leonardo is different respect to the oldest arduino. BUT i have read that there can be problems ONLY if I use the SPI library.... bat I don't use it.....
in theory I should use only the RX, TX, and digital 2 pin..... and use the Serial1 class in the firmware....
There could be any conflicts regards the other interfaces and the arduino yun, even if i don't use them ????

Thank you for your answer
Piero76

2014-03-13 21:39:34 Hello Piero,

Did you plug the jumper caps on the RS485 side?
There are there "RS485/TTL selection jampers" on the board, please plug them to the RS485 side.
Could you attach your hardware connection and your sketch here? Grey.CC

2014-03-13 06:08:24 Hi all

for myactual project i need to use your I/O expansion shield v5 (using rs485) with my arduino yun.

i've already tested the sketch with a UNO and it works fine. when i use it on Yun i've some problem
i see the data coming via serial monitor but not from the rs485 interface. Have you tested the shield with the YUN/leonardo?
there's something to modify to make it works?

thank you Piero76