Adding Eagletree Airspeed sensor in FRSKY code

[Bruneaux]

I'm trying to add an airspeed indicator sensor. I've got the code down to the FRSKY.CPP and SPORTFRSKY.CPP code and I have figured out the (proper?) way to read the packets. But I am having problems finding where the packets are pushed out. I would have expected a round-robin method to send out packets for each packet that is expect to be polled.

There is a "frskyPushValue' but it is only called within "void frskySendNextAlarm(void)".

Can someone help guide me toward the proper place/code?

Thanks

Bruneaux

Note: I've been told that FrSky uses basic I2C protocol, thus a polling method is expected. Let me know if it streams (thus there is no way in do this).

[Kilrah]

The telemetry link is only one way (except for D16, but uplink isn't implemented at this point).
FrskyPushValue is used to send configuration data to a DxT module.
Not sure if I understand what you're looking for.

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[Bruneaux]

I've updated my post.

Thanks for responding, Kilrah.

Note: I've been told that FrSky uses basic I2C protocol, thus a polling method is expected. Let me know if it streams (thus there is no way in do this).

In the I2C protocol the sensors are polled. Sending a start and a value indicating the sensors ID to read. The sensor then sends it's value(s).

Is sounds like you are saying that the data is streaming, not polled.

Is that correct? In that case there would be not way to make this sensor (EagleTree Airspeed sensor V3) work because I can't send the code to the sensor.

Brunueax

[Bruneaux]

Hmm, I thought the Smart Port was bi-directional.

[MikeB]

FrSky SPort is polled, but it is NOT I2C. It uses a bi-directional signal that carries asynchronous serial data at 57600 baud. If the EagleTree sensor is I2C, then you will need something (Arduino?) to interface between the two. The openXsensor project does just this, interfacing to FrSky protocol on one side and I2C to a pressure sensor on the other.
I'm just looking into why the SPort part is not working properly!

Mike.

[Bruneaux]

It is possible that the receiver polls the sensors and adds that data to the stream. If that is the case then the code that I need is within the receiver. That would make this very difficult to implement.

Note: the information that used to be on FrSky's site (detailing the I2C protocol for the sensors) has been pulled. I think it was a PDF; does anyone still have that file? I believe it was "HubProtocol.pdf".

Thanks

Bruneaux

[Bruneaux]

Mike,

To be clear, I have not tried using the S-PORT yet. Who indicated that it was not working?

Hope I have not confused you.

Bruneaux

[Bruneaux]

Mike,

I believe that FrSky used I2C prior to the SPORT. But that might be hidden through the hub or the receivers code. When the Hub is attached to SPORT Vario it is bridged so the older style sensors can still be used (since there no other NEW sensors out yet!! ).

This does work: (old sensors) ==> Hub (data port) ==> SPORT Vario ==> SPORT X8R.

So the hub might be doing the I2C work and converting it to a stream of data for the S-Port.

Bruneaux

[MikeB]

The HubProtocol.pdf detailed the asynchronous serial data (9600 baud) sent by the hub to the serial input on the D series receivers. THe hub may well have used I2C to "talk" to certain sensors.

The SPort protocol is quite different. The signal line is bi-directional, the receiver sends a poll request and an ID out, then listens for any response. Again the data is asynchronous serial but at 57600 baud.

Mike.

[ReSt]

[quote="Bruneaux"] I think it was a PDF; does anyone still have that file? I believe it was "HubProtocol.pdf".
/quote]

Is it this, that you are looking for?

Reinhard

Protocol V02 FrSky Hub.pdf

(47.7 KiB) Downloaded 450 times

[Bruneaux]

Mike,
Thanks. To be clear, though, any device can talk through SPORT, can't they? So when you say

"the receiver sends a poll request and an ID out, then listens for any response.?

it could be any device, including the transmitter. Correct?

I'm just going by the little bit that I got from FrSky. And that would make things very interesting.

Bruneaux

[Bruneaux]

Reinhard,

Thanks. That could be the one!

It does speak of (input/output). But it doesn't make sense if it just streams.


I saw it on the sight and I did download it, but my version was corrupt and then the page disappeared.

Bruneaux

[Bruneaux]

Mike,

Thanks for the info:

The openXsensor project does just this, interfacing to FrSky protocol on one side and I2C to a pressure sensor on the other.

I've Googled for "openXsensor" and I have not found it. If you know where it is could you link it?

That would work if I can find it.

Bruneaux

[Kilrah]

Search for openxvario, and look at the openxsensor branch of the code.

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