#Help needed with b777 MCP

1 messages · Page 1 of 1 (latest)

raw aspen
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hi all.
sorry in advance im pretty sure this issue has been asked and explained before.

I am quite new to Sims, but im trying to make a desk top training aid for my wife to use. she is a b777 pilot.
So please forgive my ignorance about not only the plane, but the sim and software

up to this point I have been focusing on completing the hardware side of the project

but im now trying to get everything working with and talking to the sim (msfs 2020 running a PMDG b777)

I have got most simple buttons, switches, and LED annunciators working

but im having difficulty with

1/ the IAS / Mach 7 segment display
2/ the annunciators at the left of the 7 segment display windows

and possibly some other small issues

I'd really appreciate some input / help

honestly im getting a bit confused with all the info I find about

offsets
WASM
FSUIPC

I have found successfully most of the named parameters, and assigned them to the relevant pins on my arduino pro mega.
also have set up and got outputs from some 7 segment displays

from my understanding mobiflight seems to recognize the numerical output that should be on the display, but displays nothing

thank you in advance

20260218_215406.jpg 20260218_215121.jpg
rigid harbor
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Can you find out, why there is an exclamation Mark (!) in the line of the IAS?
Maybe a wrong/defective pin?
Or test with another display.

north mirage
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Does the IAS display any test value when done inside the output config?

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If not, that would point to either the digits not being correctly selected, or a hardware issue.

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Post screenshots of the output config display tab.

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Is there any precondition set for this?

raw aspen
#

ok, so found something, and made some progress

7 segment was displaying numbers when tested. so the display works

I was playing around with the precondition tab, and had a precondition on, this was causing the error

on removing this i now do get some output on this 7 segment 🥳

however.
I now need to get to grips with making it accurate for the behavior of the MCP in the plane

I understand there is some challenge to getting Mach displayed with a decimal ie 0.85

and IAS displayed appropriately.

plus updating when specific buttons are pressed ?

honestly, don't even know where im supposed to type these logic codes / equations

if anyone has suggestions for tutorials on this id really appreciate it

and thanks for the input so far

north mirage
#

One way is having two output configs, one for IAS and one for Mach (with explicit decimal point). Use preconditions to control which one is active.

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You will need to have Mach multiplied by 100.

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You can use padding modifier to place a leading 0.

raw aspen
#

hi all

ok so im trying to make a press of the IAS button make a mobiflight variable and each press toggle between value s 0 and 1 respectively with the logic

if($= 1,0,1)

then im trying to use 2 separate configuration to display IAS or Mach

im hoping later to use this same mobiflight variable to illuminate the IAS or Mach indicator too.

on trying this though all lines in mobiflight have the red exclamation, and now nothing works

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any advice greatly appreciated

raw aspen
#

ok, so sorry possibly things may be partially working

I have ths sim running now mobiflight seems happier

im however expecting one of the 2 configurations to be showing red error message. and the button to toggle between the 2

in 1 state I get 1 error. and a n expected display

in the other state I get no errors, and a flickering mess on display

is this my display trying to display both, my precondition not working...
?
any input?

north mirage
#

In general, you want the Sim to be the source of all truth. So, it will be better to use a Simvar that contains the IAS/Mach status to decide what the display should show.
Your button sends the IAS/Mach toggle command to the Sim; the Sim switches the IAS/Mach mode in the MCP, and updates the mode status variable. Mobiflight reads the status from the Sim and changes the display accordingly.

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By using a MF variable instead of a Sim variable, you are bypassing the Sim.

raw aspen
#

hi all

again thanks for the help

I feel im making some progress, but running into some challenges

the areas im working on are the IAS or Mach indicator at the left of the speed 7 segment

having little luck with this

but made some progress with the HDG or TRK indicators

I have set a line in mobiflight to 'read' the boolean value from the sim.

then setting the precondition for each LED based on this .

as the button toggles, and the sim state changes, I see 1 line the the other meet the condition, and the other shows the error message

however when in use the button press will illuminate the second LED, but the first stays on.

im assuming I will have the same issue with the IAS / Mach, so im trying tho troubleshoot this now

thanks again

north mirage
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Preconditions do not change the value of any output. None. They prevent or allow Mobiflight from processing an input or output.

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You don't normally need to use preconditions with led outputs.

raw aspen
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Ok

so seems this was not the correct approach to this issue

so I have found the offsets for the sim function I want to represent on my MCP

I want led A to light in state 0
and LED B to light in state 1

how is best to do this?

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I was forcing an output of 1 on 2 separate configuration lines and using a precondition to disable one or the other.. but it doesn't seem to work as I hoped

north mirage
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For led B, it is trivial to setup as the simvar value already represents how the led should behave. Yes?

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For led A, you use the same Simvar and add a Transform modifier with the formula 1-$