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Re: Inter-Display link protocol documented

Posted: Thu Feb 11, 2016 9:07 pm
by MolsonB
4a) Is there a place where we can submit a ticket for future requests to add another fuel tank?

4b) So the 'Send Analog Inputs' only sends certain functions (ILS, Dimmer, Hold/Seq) but not when we select an Analog input as an Aux (EIS compatible). How do I send Remote Analog Aux 0-16? Is that the Can Bus remote you are talking about?

I'm trying to think of the best way for the HXr to handle the A/D conversion for the fuel level probes (analog inputs 0-3), and then be able to share them across the interlink. If it's not possible, I'll have to handle my own A/D conversion and send the fuel levels via EIS aux. I was playing around, there is no EIS2 interlink ?

Re: Inter-Display link protocol documented

Posted: Fri Feb 12, 2016 3:28 am
by GRT_Jeff
4a) I'll add it to my list.

4b) When you configure the Remote Channel for an analog, that analog is included in the Send Analog Inputs data.

The two-engine mode on the HXr is currently only implemented for direct wiring. EIS2 is packet 27 but it will not activate the extra graphics.

Re: Inter-Display link protocol documented

Posted: Sat Feb 13, 2016 10:08 pm
by MolsonB
Excellent. I'm receiving the raw analog inputs from the HXr. I'll just have to copy the fuel tables to my program to convert the raw value into fuel levels. Then send the total fuel BACK to the HXr via EIS to give the 'fuel total'. I couldn't see an option in the HXr that automatically adds the left,center,right fuel values to give the 'fuel total'. Besides setting it manually via buttons "more" -> "engine" - > "set fuel". Maybe on the manually screen, there's another button that you can push that will already add the fuel levels for you? Or have a missed something.

I'm almost there with HXr having enough serial inputs now. I just have to offload 1 more serial port to my program. The GPS is like the EIS, slow and 1way, so I might do that. I don't have any AHRS hooked up, so I can't analyze the GPS interlink stream. Seems like the Mini doesn't share it's GPS via interlink either. Could you give me the lowdown on the GPS packets? If you guys come out with an IFR GPS, please make it USB. lol.

1. Com1
2. AHRS1
3. Com2
4. AHRS2
5. Autopilot
6. Interlink
7. PAC Audio
8. VPX

1. Interlink
2. Autopilot
3. Transponder

1. MegaSquirt (EIS data)
2. GPS
3. Bluetooth to my Android app

Thank you Jeff for all your help.

Re: Inter-Display link protocol documented

Posted: Tue Feb 16, 2016 3:37 am
by GRT_Jeff
Normally, the "Fuel Total" comes from the fuel flow function: you set the fuel total and the fuel flow is subtracted. It will work your way because the EIS fuel total will override the EFIS fuel total. The only display feature that sums the individual fuel levels is the Fuel Remaining bar graph. The main part of the bar graph is the Fuel Total from fuel flow, but it also includes a diamond that is the sum of the fuel levels.

The Mini will share its GPS when it's selected by NAV MODE.

Packet type 9.
Byte 0: 0 (GPS position packet)
Byte 1: Last two digits of year (year mod 100), zero if unknown
Byte 2-5: packed LSB first: month (4 bits) | day (5 bits) | hour (5 bits) | min (6 bits) | sec (6 bits) | status (1 bit)
The date and time fields are all zeroes if unknown.
The status bit is 1 when the GPS has indicated its data is valid.
The EFIS may try to use this data as a time source if the day is non-zero and status is 1.
Byte 6-9: latitude (32-bit float)
Byte 10-13: longitude (32-bit float)
Byte 14-15: Ground track in tenths of a degree, MSB first
Byte 16-17: Magnetic variation in hundredths of a degree, MSB first, positive west
Byte 18-19: Ground speed in tenths of a knot, MSB first
Byte 20: bit field
Bit 0 = GPS2 input is configured on this unit
Bit 1 = This data is from GPS2

Re: Inter-Display link protocol documented

Posted: Wed Feb 24, 2016 3:45 am
by MolsonB
Can the interlink send all the necessary info the HXr would need for GPS? It doesn't need the rest of messages? Geographic Latitude and Longitude (GPGLL), DOP and active satellites (GPGSA), Satellites in View (GPGSV)?

I have to free up one more 'serial port' to get everything to fit on a single HXr. I was thinking GPS would be the easiest, but I don't feel warm and fuzzy being the middle man for GPS. Would a Com2 (Trig TY91) be simple packets to RX/TX instead? or PAC15EX? If you guys build a 'serial port extender' box via Ethernet cable, I'll be the first to test it.

Now that I'm back in the states working on the plane for a month, I have access to my adaptive AHRS and can receive the raw GPS data to paraphase into interlink packets. But no Mini/HXr to test on.

Re: Inter-Display link protocol documented

Posted: Thu Feb 25, 2016 1:26 am
by GRT_Jeff
The link data is enough to display GPS position. We get GPS altitude from GPGGA, but that information is not currently sent over the link. The GLL/GSA/GSV data is only used to display the GPS Status page, so we don't send it over the link. There are other messages to transfer external flight plan data if it's a panel or handheld GPS with a flight plan function. The Trig COM and PAC15EX are not good interfaces to do yourself.

I just found out we're making a 1:4 serial multiplex board that uses serial. I don't know if/when it's going to integrate with the HXr yet.

Re: Inter-Display link protocol documented

Posted: Fri Jan 13, 2017 2:47 pm
by MolsonB
The AHRS serial out, could that be shared? Actually let me be more specific. I'm looking for the IAS and altitude, is any of it calculated inside the HXR, or are all calculations done inside the AHRS?

If the HXR massages the data before display, my best bet would be to hijack the GRT data out to the VPX.

Re: Inter-Display link protocol documented

Posted: Fri Jan 13, 2017 11:18 pm
by GRT_Jeff
IAS and pressure altitude are computed in the AHRS. The HXr adds a little more filtering and hysteresis. The HXr also adds the baro correction.

Re: Inter-Display link protocol documented

Posted: Mon Jan 16, 2017 2:14 am
by MolsonB
Ok, I'll hijack the VPX data out then. Thanks Jeff.
GRT_Jeff wrote:IAS and pressure altitude are computed in the AHRS. The HXr adds a little more filtering and hysteresis. The HXr also adds the baro correction.

Re: Inter-Display link protocol documented

Posted: Sun Oct 01, 2017 5:31 am
by MolsonB
The addition of 'Air/Ground Transition speed', is that flag being passed on inter-display? I'm basically trying to find out when we are flying vs on the ground. Right now I'm using the GPS ground speed (better then nothing).