[fpga-miniconf] litevideo VGA on arty WIP

[Hasjim Williams]

Hi Florent,

So, I just need to do something like:
https://github.com/futaris/litex-buildenv/blob/master/targets/nexys_video/video.py#L128
Is this the best documentation on how the mmcm & clocking works
on Artix-7?https://www.xilinx.com/support/documentation/user_guides/ug472_7Series_Clocking.pdf
HDMI/DVI clocks 10 times faster for the pixels, compared to the main
clock, right?
VGA clocks once per pixel, so I will probably have to modify that.

Can I hard code the pixel clock in the gateware, rather than use the
pix clock?
Hasjim

On Mon, Feb 5, 2018, at 6:36 PM, Florent Kermarrec wrote:
> 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/tutorials/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
>>>> 
>>>> --
>>>> fpga-miniconf mailing list
>>>> fpga-miniconf at lists.lca2018.linux.org.au
>>>> http://lists.lca2018.linux.org.au/mailman/listinfo/fpga-miniconf
>>>> 
>> 

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