Additional UART connections for Myrio

[jtbelter]

As part of a Racecar monitoring system, we need to interface with 4 separate UART streams.  As with adding additional encoder pins or i2c, I tried to modify the FPGA personality by copying and pasting existing blocks but cannot find where/how the UART channels are integrated into the FPGA personallity.  Can you tell me how to add two addition UART channels to my Myrio? 

Thanks,

Joseph Belter

Bulldogs Racing Team

[RyanPoPo]

Hey Joe,

Can you provide some more information about the UART that you are using? How does it connect to the myRIO? Does it communicate with the myRIO using RS-232 communication or some other method? To help you figure this out, I need to understand how the hardware you have is intending to communicate with the myRIO.

The more details that you can provide, the quicker we will be able to help.

Regards,

Ryan

[Kristoff2]

Hey Joseph,

As you mentioned the UART is not implemented in the FPGA on myRIO.  The UARTs on myRIO come directly from the Zynq chip (if I recall correctly).

If you need to add more UARTs you have a few options.  You could try to add UARTs in LV FPGA.  A quick search turned up some promising leads.

https://decibel.ni.com/content/docs/DOC-1290

https://decibel.ni.com/content/docs/DOC-29838

Another option would be to use a USB / Serial converter.  I posted some documentation about getting a USB / Serial device working with myRIO here.  Devices using an FTDI chip for the USB / Serial conversion should not require and Driver level OS modifications, just a little help to get them recognized by VISA as described in that tutorial.

Let us know if that helps or if you have more questions about this.

Thanks!

-Sam K

LabVIEW Hacker

Join / Follow the LabVIEW Hacker Group on google+

[jtbelter]

We are currently communicating to two separate GPS units, which both are 3.3v TTL and use the default UART connections on the Myrio with the UART Express vI.  We need to talk to one additional battery monitoring system which is RS232 (which we can convert to 3.3v TTL) and we need to received data from a second MyRio.  To communicate data between two myrio's there may be a better option but we thought a simple serial string would do the trick if we can establish more 3.3v TTL pins.

Thanks for the comments about using the USB-serial converter.  The tutorial looked like it would work but since we need this to work repeatedly on power-up, we cannot use that method.  

Any additional thoughts on how to get additional 3.3V TTL (similar to the ones that currently exist by default on the myrio ) would be appreciated. Standard baud-rates are fine.

Thanks,

Joseph Belter

[Kristoff2]

Will the two myRIO's be on the same network?  If so you could use shared variables or networks streams to communicate between the two.  If they will not be on a network you could use a new myRIO features in 2013 SP1 that allows you to host an add-hoc network on the myRIO.  This would let you connect one myRIO to another via WIFI with no other networking gear (ie no router involved).

If you want to go the USB / Serial converter route I'm sure there is a way to make that change last though reboot.  I just didn't get that far yet.  I'll check if there is any easy way to do this.

Thanks!

-Sam K

LabVIEW Hacker

Join / Follow the LabVIEW Hacker Group on google+

[ALEX_1989]

Hi, i also faced the same problem that wanna connect MyRio with more than 2 UART ports. 

I just check the link that you provide for process of adding a USB Serial device (such as an FTDI) to myRIO so it can be accessed using VISA VIs in LabVIEW.

it seems can't open the link "

1. SSH into the myRIO" at the first step of this process.

[Miro_T]

Hey, 

It looks like the LabVIEW hacker article is not accesible but maybe this will help

http://digital.ni.com/public.nsf/allkb/9822A3A39B1D0CBB86257C55006B962A

[Kristoff2]

The LabVIEW Hacker tutorial is here.

-Sam K

LabVIEW Hacker

[ckyamaha]

Hello, I also need additional UARTS on myrio and i am trying to connect the PMOD USB to UART

https://www.digilentinc.com/Data/Products/PMOD-USB-UART/PmodUSBUART_rm.pdf

After connecting it, it is identified and displayed in NIMAX and also in the webinterface of MyRio, however it says not present in its status (attached screenshots). When i try to open the VISA test panel in NIMAX i get the following error:

Error opening resource:
visa://10.20.22.52/ASRL3::INSTR

VISA:  (Hex 0xBFFF00A8) Access to the resource or remote machine is denied. This is due to lack of sufficient privileges for the current user or machine.

I have also tried the LabviewHacker tutorial below but it did not work out.

https://www.labviewhacker.com/doku.php?id=learn:software:national_instruments:myrio:tutorials:usb_se...

First of all the step 2 of this tutorial is not possible because the /etc/mdev.conf is not available on myrio

Any clue what is going on?

Thank you,

Christos

[ckyamaha]

Hello again,

I am still stacked with the above problem. I would really appreciate anyone's help on this.

Thank you,

Christos