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Visitor group53_aes
Visitor
257 Views
Registered: ‎06-06-2019

Connection from PC to ML506 using RS232

Hello! 

I am trying to connect FPGA ML506 board to PC for serial communication using RS232; Basically, we are using UART for serial communication. While doing pin assignment in UCF we didn't find any pin for RS232 in the datasheet. Can anyone help in this as soon as possible or is there any other way rather than this would also appreciate.

 

Thank You!

 

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9 Replies
Scholar drjohnsmith
Scholar
244 Views
Registered: ‎07-09-2009

Re: Connection from PC to ML506 using RS232

Look in the example code for the board provided on line .

    here is a start,

https://www.xilinx.com/support/documentation/boards_and_kits/ug348.pdf

 

RS232 is a +- 12 v standard, and Virtex can not handle that level ,so there is a Rs232 serial driver / receiver chip on the board.

My guess , and thats all it is, is that the RS232 is to the "processor" in the fpga code.

Visitor group53_aes
Visitor
235 Views
Registered: ‎06-06-2019

Re: Connection from PC to ML506 using RS232

Thank you for your reply!
But we didn't get what to write in UCF file to generate the BIT file.
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Scholar drjohnsmith
Scholar
222 Views
Registered: ‎07-09-2009

Re: Connection from PC to ML506 using RS232

Ok, where have you looked ?

 

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Visitor group53_aes
Visitor
218 Views
Registered: ‎06-06-2019

Re: Connection from PC to ML506 using RS232

Hey,

We searched in ML506 datasheet, but we did not find any pin number. 
here it is: https://www.xilinx.com/support/documentation/boards_and_kits/ug347.pdf

So our requirement is to send 128-bit data from PC to FPGA(ML506). For that, we wrote the code for UART. And we are sending this data through RS232 cable to "serial comp port 1" of FPGA.

We have attached UCF file screenshot with it and our ML506 kit board pic, a quick response will be appreciated. 

IMG_20190607_154109163.jpg
xilinx.JPG
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Scholar u4223374
Scholar
208 Views
Registered: ‎04-26-2015

Re: Connection from PC to ML506 using RS232

If you do a search for "ML506 schematic" you'll find that - which tells you just what you need. FPGA_SERIAL1_TX is on AG20, and FPGA_SERIAL1_RX is on AG15.

 

As noted in the user guide, you will need a null modem cable for this - although that's not hard to build.

Scholar drjohnsmith
Scholar
194 Views
Registered: ‎07-09-2009

Re: Connection from PC to ML506 using RS232

There are example designs to use,  like the hello world, just look in there,

   but this is my way of doing this.

 

start with the schematics :

https://www.xilinx.com/support/documentation/university/XUP%20Boards/XUPV5/documentation/ml50x_schematics.pdf

sheet 1, tells yo uthat the UART , which is a way of saying "RS232" / "serial", is on sheet 12.

 If you go to sheet 12, you find connector P3, which I htink is the connector your pointing at.

then following th esignals to the left, you see thay are named fpga_serial1 .  

If you then search the scheamtics for those signals , you see thay are on sheet2, fpga bank 4, pins AG15 and AG20.

 

 

Hope that helps, its a good skill to have ,

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Visitor group53_aes
Visitor
188 Views
Registered: ‎06-06-2019

Re: Connection from PC to ML506 using RS232

Thanks for your help and your quick response, it helps a lot.
As our working machine doesn't have a serial port so we are using USB to UART converter module(Silicon lab CP2102 USB to UART Bridge). We verified it and it is working properly.

Do you think this will affect our data communication because as it mentioned in the "ML506 Evaluation platform" ;
"The FPGA is connected only to the TX and RX data pins on the serial port. Therefore, other
RS-232 signals, including hardware flow-control signals, are not used. Flow control should be
disabled when communicating with a computer."
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Scholar u4223374
Scholar
178 Views
Registered: ‎04-26-2015

Re: Connection from PC to ML506 using RS232

The CP2102 should be fine. USB-RS232 adapters are very reliable these days.

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Scholar drjohnsmith
Scholar
171 Views
Registered: ‎07-09-2009

Re: Connection from PC to ML506 using RS232

Ah the good old days of null modem, dtr , ctl etc etc etc.

Serial links / uarts / rs232, are basicaly simple ,

On the 9 pin D, pin 5 is gnd, 2 and 3 are Tx and Rx , You note, I did not say which is Tx and which is Rx,

Thats where the "Standard" was abused and miss used, SO engineers of old had a bunch of 9 pin plugs and sockets and jumpers to connect these things,

Then you add the how many bits / start / stop bits, before 'every one' ended up at 9600, ( or 11520 Baud ) , 1 start 1 stop, no parity .

Oh you miss all this fun.

The flow control signals are from the days of 'audio modems' and tele types ! Look them up, but basically the link had to work out if both ends were ready to send and accept data,

In theory, "all" you should need is pin 2,3 and 5, and swap pin 2/3 to get a connection !

A tip , if you see ;crazy characters' on the terminal you probably have the baud wrong.

Just about any usb to rs232 adapter will work, provided you pc has the drivers.

I do note, this board has ethernet and USB, and example designs on how to use them, which you might find usefull for future.

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