Hi ioio users, Ytai ,...need your science again ; )
I've not found some precise info about this kind of topic...So I create new
one.
I'm trying to understand the way of doing TWI between ioio and arduino uno.
I use an arduino as a slave for driving 2 sensors.
>From these two sensors, I've get 2 vars
float *voltage_value*
unsigned long *lowpulseoccupancy*;
And I simply need to get those values back on my android program.
So, in the ioio android program :
In the setup(), I need to declare the twi master
twi = ioio_.openTwiMaster(1, TwiMaster.Rate.RATE_100KHz, false);
The "1" means that I'm using the SDA1 (pin1) and SCL1(pin2).
The rate means the bit rate of exchange... I think for arduino it doesn't
matter.
The false, for use the standard voltage 3.3V
Then in the loop I need to use it with first declare a request and response
as byte[]
I don't know if I cannot use the request parameter and replace it by
null...cause I don't need to send something but just retrieve data. Right ?
request = new byte[] { 0x01 }; ??? I don't know the mean of
creating a byte array in request...
response = new byte[8];
if (twi.writeRead(arduino_id, false, request, request.length,
response, response.length)) {
for (int i = 0; i < 8; i++) {
System.out.println(response[i]);
}
}
I've connected the ioio SDA1 and SCL1 to arduino pins near aref pin.
Normally these arduino pins are the dedicated ones for arduino layout R3.
And I do not forget to add pull up resistors to 3.3Vcc
Into the arduino program : (with importing the Wire library )
void setup(){
Serial.begin(9600);
Wire.begin(123); // arduino_id = 123 and means
that its a slave in the twi protocol.
Wire.onRequest(requestEvent); // register event fct
Wire.onReceive(receiveEvent);
}
void receiveEvent(int i)
{
Serial.println("RECEIVE !!!");
Wire.write( the float or long I need ) //voltage_value
and lowpulseoccupancy
}
or
void requestEvent()
{
Serial.println("REQUEST !!!");
Wire.write( the float or long I need ) //voltage_value
and lowpulseoccupancy
}
I've added the two function event to see what's happening in serial
monitor...
Cause, normally, I suppose that at each new request from the ioio twi and
using the right arduino slave address,
the arduino will launch one of these event function...But for now...nothing
is printed. Grrr..
I suppose the onRequest will be handled cause I don't pass any parameter
with twimaster. But I'm not sure.
Also I don't know if the arduino_id address is in a correct format...
I've seen some web forums mentioning either Wire.begin( in hexadecimal )
or Wire.begin (integer format )
So...for a beginner ...Twi is not really easy...
If you could enlightened my mind of how to use twi correctly with ioio and
arduino...
Or give me a tutorial somewhere...cause I didn't find precise examples of
this...
Thanks for help again.
Lo.
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