[fpga-miniconf] litevideo VGA on arty WIP

[Florent Kermarrec]

Hi Hasjim,

it's strange you don't have at least the clock on the output. First thing
to check is that your pix clock is working.
Your changes in the firmware seem fine, but you can try to connect one led
to a counter clocked by pix_clk to make sure your are configuring the mmcm
correctly.

Florent

2018-02-05 1:24 GMT+01:00 Hasjim Williams <hasjim.williams at futaris.org>:

> Hi Florent,
>
> As I suspected, something is weird with the clocking, and the G0 output
> doesn't appear to changing...
>
> I posted some oscilloscope screenshots on #timvideos.
>
> I'm not sure that I've done the firmware code correctly. I've basically
> taken the HDMI_OUT0 stuff and search/replaced with VGA_OUT0.
>
> I haven't really looked into how the MMCM works, or the PLL on the
> MimasV2, so I'm sure I've messed up something.
>
> Is there any documentation on the simulator / verilator and how to run
> litevideo in it ?
>
> Hasjim
>
> On Sun, Feb 4, 2018, at 9:16 PM, Florent Kermarrec wrote:
>
> Hi Hasjim,
>
> great, to understand why it's not working yet you can check:
> - that the video pattern if enabled for the vga output in the firmware.
> - that you are using a correct video mode (you can start with a low
> resolution)
> - if you have a scope, have a look at the clk/vsync/hsync.
>
> Florent
>
> 2018-02-04 9:35 GMT+01:00 Hasjim Williams <hasjim.williams at futaris.org>:
>
>
> HI everyone,
>
> I managed to get Vivado 2016.4 to output VGA with the Pmod-VGA example
> from:
>
> https://reference.digilentinc.com/reference/pmod/pmodvga/start
>
> https://github.com/Digilent/Arty-Pmod-VGA
> https://reference.digilentinc.com/learn/programmable-logic/t
> utorials/arty-pmod-vga-demo/start
>
> I made some changes to litex-buildenv with the help of Florent, and made a
> pull request on github:
>
> https://github.com/timvideos/litex-buildenv/pull/20
>
> This is still WIP and output doesn't work on Pmod-VGA yet in the hdmi2usb
> firmware.
>
> I don't think it's clocking out the pixel clock, hsync and/or vsync
> correctly yet.
>
> Hasjim 'futaris' Williams
>
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>
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