Beware dodgy Hardware!

[lesthegrngo]

I need to warn you all of something that may cause you weeks of frustration

 

I have been trying to set up parts to use with DCS Bios, and for the last couple of weeks have kept on running into roadblocks that meant my putative cockpit instruments weren't working.

 

to cut a long story short, it turned out to be a mis-named pin on an Arduino (a mega in this case) which meant that it didn't matter whether my wiring was correct as the Arduino pin that I was using was the wrong one.

 

I assume that the blue (incorrectly stencilled) mega in the picture is a Chinese clone, and for the most part my experiences of the clones has been good. However, this one was one of the not so good ones. If you check it against the 'branded' version below it, you can see that the TX and RX pins are transposed.

 

Checking against the Arduino Mega specifications, the blue one has got it wrong. That simple error has lost me a ton of time and also cost me money, so if you are experiencing issues, a five minute check may save you unnecessary problems.

 

Hope this helps

 

Les

Edited June 29, 2019 by lesthegrngo

[Jester_ITA]

It definitely helps!

I had the same problem when I tried to run the 485 bus.

RX and TX reversed and months trying to solve the problem without realizing it.

I can not write here, because of censorship, my exact words when I realized ;)

I had given some answers to those who had problems in other posts but, in fact, it is better to do a specific post about it!

Thank you!

 

EDIT: Look at that ... "COMMUNCIATION" ... they can't even write correct words, just figure the pin markings! :lol: :lol: :lol:

Edited June 24, 2019 by Jester_ITA

[crash test pilot]

"COMMUNCIATION" seems to be correct; my new chinese mega-clone (looking identical to yours) is labeled with all pins acording to arduino-specs but still says "COMMUNCIATION"

[RustBelt]

I assume that the blue (incorrectly stencilled) mega in the picture is a Chinese clone,

 

What Makes you think that?

:drink:

[lesthegrngo]

At least they spelled that bit right.....

[Hansolo]

To be fair the black one from Elegoo is also a chinese clone :smilewink:

 

Mislabeled boards can of cause be avoided by buying the original product. They just cost more but have the ATmega8U2 or ATmega16U2 USB chip as opposed to the cheaper CH340G;

https://www.quora.com/What-is-the-difference-between-Arduino-Uno-R3-compatible-board-ATmega328P-ATmega16U2-and-Arduino-Uno-R3-ATmega328P-USB-board-CH340G-Which-should-I-buy-and-why

 

Despite the mislabeling I'd expect to continue buying the chinese ones. So far I haven't had any issues with them.

 

A way to avoid the mislabeling is to just use UART2 and/or UART3;

 

/*
 Tell DCS-BIOS this is a RS-485 Master.
 You will need to flash this to a Mega 2560.
*/
#define DCSBIOS_RS485_MASTER

/*
 Define where the TX_ENABLE signals are connected.
 You can connect up to three half-duplex RS-485 transceivers.
 
 Arduino Pin             RS-485 Transceiver Pin
 TXn ------------------- DI (driver input)
 RXn ------------------- RO (Receiver Output)
 UARTn_TXENABLE_PIN ---- /RE, DE (active low receiver enable, driver enable)
 
 If you have less than three transceivers connected, comment out the corresponding
 #define UARTn_TEXENABLE_PIN lines for receivers that are not present.
*/
//#define UART1_TXENABLE_PIN 2
#define UART2_TXENABLE_PIN 3
#define UART3_TXENABLE_PIN 4

#include "DcsBios.h"

void setup() {
 DcsBios::setup();
}

void loop() {
 DcsBios::loop();
}

 

 

@lesthegrngo, perhaps re-name the thread to 'Mis-labeled Arduino Mega' as the hardware as such isn't faulty. Its a typo but an inconvenient one.

 

Cheers

Hans

[lesthegrngo]

Fair point, Hans, however I think the thread title is not something that can be changed unfortunately. I'm happy for the moderators to do so

 

Cheers

 

Les

[JG14_Smil]

I once bought a power supply that had the polarity backwards. Now we are back on topic.

[Gman109]

What exactly is "dodgy" hardware? Is that hardware that somehow dodges you are something?

[lesthegrngo]

A distictly British phrase, 'dodgy' means something that is untrustworthy or unreliable

 

Cheers

 

Les