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[DCS-BIOS] Is com-handler working?


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Hi all, that's my first post here so i think i might introduce myself.

I'm Maurizio from Italy, i'm a long time flight sim enthusiast and recently i decided, after looking at DCS-Bios, to build something that resembles an A-10C cockpit.

I would thank a thousand times Ian and everyone involved for the work on this software!


While i cannot (still) make RS485 bus to work, i've tried com-handler to simplify the managing of all the com ports involved but it's not working.

I mean, i can see the counter "from DCS" to increase but the "from COM" counter is stuck on "0" and nothing works in the cockpit.

With the "connect-serial-port.cmd" script everything works.


Am i doing something wrong?


Thanks for the help!



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The com-handler still assumes a serial connection speed of 500000 bps. This was changed a while ago to 250000 bps and the com-handler was never updated by its author.


I plan to integrate similar functionality into DCS-BIOS 2.0, but that is still several months away at this point.



What issues did you have with RS-485? What transceiver chips did you use?

Edited by [FSF]Ian
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Thanks for the reply Ian.


Well, i've opened the com-handler sources to try to modify it but i'm still looking into it.

Do you know, by chance, if it's enough to modify the code where it sets the baud rate or if there's other kind of modifications?

I'll make some tests this afternoon.


About RS-485, i'm using the Max485 ttl adapter as in this article



At first i was operating without resistors but no joy. Then i added resistors (hoping to have them calculated correctly) but again no joy.

The Mega has the tx led working but the second mega don't work.

Testing with another sketch, wich sends characters with the master serial monitor and receives them back from the slave, i have garbage coming back but never a clean response.

I'll do a screenshot this afternoon and try to explain better.

I know, reading this forum, that the 487 are better than the 485 that i'm using but i had those "in house" and i've tried them, probably i should switch?


Thanks again!

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Yes, changing the baud rate is the only thing that would need to be modified about the com-handler.


For new projects, I would recommend MAX487 chips. On the other hand, those modules with the MAX485 on it are all over eBay and AliExpress and this is the second or third time someone has posted that they couldn't get them to work, and it won't be the last. I just ordered a pair of those so I can figure out how to wire those up in a way that makes DCS-BIOS work.

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Indeed, i found them on ebay at a very cheap rate. Maybe it's for that they're not working :lol::lol:

A friend of mine once said "Low expense, low performance!"


I have four of them, tried to switch to find out if one was fried but the response is always the same.

I think they're not completely broken, something is coming back in the serial monitor, but like when the baud is different and it receives garbage.


Maybe i can try to order another pair (the cost is not so prohibitive!) and try again.

I'll try also max487 but without the possibility of creating my own pcb, things are a little more complicated, especially when i'll have to enclose them into the panels...



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I don't think your breakout boards are broken. It's probably got something to do with bias resistors, but I cannot verify that until I have some of those boards on my own desk to tinker with. This will probably happen some time next week.


The MAX487 won't need any additional resistors, so the circuit is a lot simpler than what you see on those MAX485 breakout boards. Some prototyping board (stripboard) should be all you need to integrate a MAX487 chip into your circuit.

Edited by [FSF]Ian
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