Sending Data from PC to FPGA via USB-UART using Docklight

[Clutchgod]

Hello everyone,

I’m currently working on a project where I need to send data from my PC to an FPGA via a USB-UART cable. For this, I’m using Docklight as the communication tool, but I’m facing an issue. When I try to send data from Docklight, the FPGA does not seem to receive it.
I am using a custom data frame for the communication, and I’m not sure if there’s an issue with that or if something else is going wrong.
Has anyone encountered a similar problem or have suggestions on what could be causing this? Also, if there are any alternative tools that could help in transferring data from PC to FPGA via USB-UART, I would really appreciate your recommendations.


Thank you in advance for your help!

 

[dpaul]

@Clutchgod
No, sending data from PC to FPGA using UART is pretty much straight forward. I used Putty or TeraTerm from the PC and never had problems. An FTDI chip was used for the USB to UART bridge. At the FPGA for the tx/rx two GPIO pins can be used as the interface. Make sure to keep the baud at sides same.
It is a simple design inside the FPGA and even without simulating the design, it is possible to get the design working correctly in hardware.
Unfortunatel yyou have not described what you have done in details and neither the problems you face.

 

[KlausST]

Unfortunatel yyou have not described what you have done in details and neither the problems you face.

I agree.

On UART layerl you need to satisfy:
* Voltage levels: Output on one side needs to match input on the other side.
* polarity
* baud rate
* Start bit width
* data bit count
* stop bit width
* parity bit: none/even/odd

That´s it.
Maybe you have flow control - only you know.
And as usual with UART: Tx on one side needs to be connected with Rx on the other side.

****

The rest is proprietary communication protocol .. only you know.

***
All the UART level informations can simply be verified with a scope.

***
You did not mention any return data flow: from FPGA to PC. Only you know.

Klaus

 

[Clutchgod]

@Clutchgod
No, sending data from PC to FPGA using UART is pretty much straight forward. I used Putty or TeraTerm from the PC and never had problems. An FTDI chip was used for the USB to UART bridge. At the FPGA for the tx/rx two GPIO pins can be used as the interface. Make sure to keep the baud at sides same.
It is a simple design inside the FPGA and even without simulating the design, it is possible to get the design working correctly in hardware.
Unfortunatel yyou have not described what you have done in details and neither the problems you face.

i had costum uart design which had 80 bits of data frame with 4bits as start bits ,8bits as command ,24 bits of address ,32 bit of data ,8bit of CRC and 4 bits as stop bits asswell . What i'm currently facing is that i am sending data to USB-UART port with Docklight software but i did not get any data at my other end so is there any thing i'm doing wrong i did not get and i'm using 115200 as baud rate in Docklight. and if i'm use puTTy fro this much of data transfer then what configuration i have to use of what inside tool i have to use for data to be transfer.

 

[FvM]

Docklight is sending standard UART frames, e.g. 8,N,1 (start bit, 8 data bits, no parity, 1 stop bit). Custom data frames aren't supported by PC UART and can't respectively be send by a PC tool.

I'd prefer decimal or hex coded data and carriage return as frame limiter.

 

[Clutchgod]

Docklight is sending standard UART frames, e.g. 8,N,1 (start bit, 8 data bits, no parity, 1 stop bit). Custom data frames aren't supported by PC UART and can't respectively be send by a PC tool.

I'd prefer decimal or hex coded data and carriage return as frame limiter.

Docklight is sending standard UART frames, e.g. 8,N,1 (start bit, 8 data bits, no parity, 1 stop bit). Custom data frames aren't supported by PC UART and can't respectively be send by a PC tool.

I'd prefer decimal or hex coded data and carriage return as frame limiter.

I'm using a custom UART frame to send data to my FPGA, but after dumping the bit file and trying to send data with Docklight, I don’t see the expected data on the TX line. I also don't get the expected data on the RX line in my ILA.


Is there a problem with my frame structure, or any tool I can use to troubleshoot this?

 

[FvM]

Not sure if we are talking on cross purposes.

If your "custom UART frame" is comprised of 8-Bit characters, there should be no problem. Each character will be however send as 10-Bit UART frame with individual start and stop bits by the USB-to-UART bridge. Your FPGA UART must be able to decode this 10-Bit frame on the lower level.

The FTDI chip would be also able to send other frame formats, but not over Docklight and virtual COM port driver.

 

[dpaul]

@Clutchgod
For the sake of debugging......Forget your custom frame for a few days!

Can you test in hardware if using the Docklight you can communicate with the FPGA using a standard simple UART frame or not?
-- Start Bit, 8 bits data, optional Parity bit, Stop bit

If you can send and receive UART frames without problems, ony after that go for your custom framing. This will be helpful!
I do not have your hardware, I also cannot see your project. So in my opinion, step by step debugging is the only suggestion I can give you.