Hello

[jbird]

I am new to this forum and wanted to say hello.  I have just started running a few demos to try and familiarize myself with the tools and have run into a few problems. I am using an Arty board with a Microblaze processor and have successfully ran the MTDS display demos as well as successfully run a bootloader with a Hello World application.

 I would like to create a bootloader for a MTDS display but have run into some issues.  I create the project similar to the Hello World bootloader but added a pmodMTDS to ja.  I programmed the FPGA and programmed the flash like this.  https://reference.digilentinc.com/learn/programmable-logic/tutorials/htsspisf/start. 

After programming the FPGA and flash, if I don't plug in the MTDS to ja it will run the bootloader fine but be unable to find the display since it is not connected.  However once I connect the MTDS display to ja the bootloader will no longer run and it behaves as if the PC keeps seeing a device plugged into the USB port. 

Any help would be appreciated.  Here is the layout of my design in Vivado.

Thanks

[jpeyron]

Hi @jbird,

Have you tried using the How To Store Your SDK Project in SPI Flash tutorial? I will get a mtds qspi flash project for the Arty A7 35t working tomorrow. What version of Vivado are you using?

cheers,

Jon

[jbird]

Yes I used the How To Store Your SDK Project in SPI Flash tutorial to setup my project.  I am using Vivado 2018.2.  

I think I may know the cause of the problem.  I believe the display may be pulling too much current and is rebooting causing it to repeatedly appear to be unplugged.  If I unplug the mtds screen and allow the program to be loaded from flash then plug the screen back in it appears to work.  I will look into powering the display using an external source and see if that fixes the issue.  I would be interested to know if you experience the same issue tomorrow.

Thanks

[jpeyron]

Hi @jbird,

I just completed and verified a project using Vivado 2018.2, Arty-A7-35T , PmodMTDS on JA and qspi here.  The project loads from qspi with the usb cable as power without an issue.  I commented out the #define verbose so it does not sent serial data over the usb uart to the PC. The project loads much faster due to commenting out the #define verbose.

cheers,

Jon

[jbird]

Jon

Thanks for the verified project.  I tried it out and it worked.  I also commented out the #define verbose on mine and it also worked.  They both may still be affected by the screen being powered by the usb cable since they both seem to freeze after a while and cause the usb port in device manager to refresh as if it is being plugged in again.  I powered the mtds board externally and both did not exhibit this behavior.

Thanks

[jpeyron]

Hi @jbird,

I did not experience this issue but that doesn't mean the project would not benefit from being powered externally.  Thank you from sharing what you found.

cheers,

Jon

[xc6lx45]

Hi,

a random thought: I've seen LCD dot matrix panels with current draw from 300 mA down to 50 or so. The blue ones tend to be better.

Maybe upgrading the display is less hassle than providing external power.