Serial PFC Flight Console to USB

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kjbaas

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Hello All,

Like a number of home flight simmers I have acquired a on older (and now unsupported) serial Precision Flight Controls Cirrus II Flight Console (https://flypfc.com/shop/flight-consoles/cirrus-ii-flight-console/). I'm using the console with X-Plane 11 and for the most part it works really well (except for a few specific functions. Alternate Air and Pitot Heat for example.) There is also some concern that X-Plane may stop supporting the serial PFC equipment at some point (this is based on a thread in another forum and completely unconfirmed). I would like to future-proof the flight console, make the non-working functions work, and perhaps map a couple of buttons differently than X-Plane mapping.

I know a number of people have converted their PFC equipment to USB using the Leo Bodnar Universal USB Interface Boards but that would mean tearing into the system and a major re-wiring project. Since the output of the serial Cirrus II Flight Console is just a constant stream of serial hex data indicating a function and a value (for example 81 01 indicates elevator full down, 81 64 elevator full up, with a stream of values in between as the yoke is moved) my thought was to use a Teensy to read the serial values and map them to equivalent USB joystick axis and button (or keyboard) values . PFC provides a serial test program that I can use to determine all the function to serial out mapping.

I know would have to map the proper axis and buttons in X-Plane once the system and X-Plane recognized the Teensy as a USB joystick. I would also use a RS232 - TTL converter between the flight console and the Teensy to protect the Teensy. Concerns would be that the Teensy (I'm thinking a Teensy 3.2) wouldn't be able to do both functions at once. Also it appears the flight console only has 7-bit resolution (based on the decimal values of each axis going from about 1 to slightly over 100 depending on the control) whereas a conversion with the Bodnar boards would allow 12-bit resolution.

Does anyone see any issues with this approach? Any gotchas I'm not thinking of.

Thank-you in advance for any input.

--ken
 
A single Teensy 3.2 should be able to do all that without problems if the incoming serial data rate is within common specs. Can you tell the baud rate with which the console is sending?
 
The serial data rate from the flight console is 9600. I can view the data both with the PFC test program and with Putty. The test program allows for a 19200 connection, but I haven't found a way to change that inside the console.

--ken
 
At 9600 or 19200 baud, there is absolutely no risk to overflow the Teensy with incoming data and there will be enough time left to process the data and to resend it as joystick codes over USB.
 
PFC Cirrus II w/ serial connection wanting to convert to USB

Hi All,

I also have a PFC Cirrus II w/ serial connection. Also would like to upgrade machine for USB use. Is there a link, video , instruction step by step on how to do this and what materials/ software/drivers, etc. is needed. I wrote to Leo Bodnar in ref. to this and they replied back. Any help would surely be appreciated. Thank you Chris Bronton

Hi Chris,

We are working with someone else on a similar project so please check back in a few weeks. All we can offer up to now is a board to replace the input part of the system on to one of our button box boards.

Regards
Simon

> On Aug 21, 2018, at 15:22, Chris Bronton <support@leobodnar.com> wrote:
>
> From: Chris Bronton
> Email: cbronton@hotmail.com
>
> ------------------------------------------------------
>
> Hello,
> I have a Serial Cirrus II from Precision Flight Controls. Do you offer anything that I can change from Serial to USB connection?
> Thank you in advance
 
Chris,

I personally haven't gotten very far with this project, so there aren't any instructions or any kind. I was also trying to decide if this is the best route to convert the control axis as my research showed there wasn't a lot of resolution for the position of the yoke and rudder pedals (I don't remember, but it have been only 8 bits.) I'm still deciding if I want to move forward or maybe use a hybrid approach where I use the Bodnar board for the yoke and rudder.

The only thing I really don't like about the stock setup with X-Plane 11 is the mapping of the buttons on the yoke. Of course if Laminar ever removes support for the serial PFC controls I may be forced to continue development. Of course it now sounds like Bodnar may also come out with a solution.

-ken
 
Do any of you know where I can get a description of PFC's yoke serial output? What do the data look like which describes pitch, roll, and yaw control input? Failing getting their serial protocol, a copy of output from an existing installation would be really helpful.

I'm working on an autopilot and I need to fly X-Planes so I can iterate my screw-ups quicker.

Thanks for any guidance which would help with this.

john ferguson
 
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