More informations

[smaffer]

Hello,
i am interested in your project. I am trying to write a similar project for ESP8266.
Is this project working?
Can you share more informations about pin wiring? Which resistor need to be used?

Thank you,
Sandro

[hchunhui]

Hi,

The project is working. It can output ascii and chinese charcters recieved over wifi.
The VGA driver provides a 512x480 framebuffer, so it is possible to output monochrome images too.

Build:
Put the project in the esp sdk directory, and type "./gen_misc.sh".

Wiring:
GPIO13 <--(330ohm)--> R, G, B
GPIO4 <------------> HSYNC
GPIO5 <------------> VSYNC

Usage:
The esp8266 sets up a wifi network called "esp". Connect to the network and redirect text to 192.168.4.1:88.

Chunhui

[smaffer]

Hello!
i have build a library for Arduino reusing your awesome work! https://github.com/smaffer/espvgax

Using Arduino ESP8266 i have found some problems when Wifi is turned ON.. Many screen flickering and the Wifi signal sometimes can't work properly. Your VGA signal is always stable?
Thank you!

[hchunhui]

espvgax is awesome!

I have the same problem when using Wifi (the screen flickers).
I think it is because the interval of the VGA timer (32us) is smaller than
the minimal interval of the esp sdk guide (50us).

I found the problem is mitigated when using 160Mhz running speed.

[gwstaten]

I have been trying to use a nodemcu to make a vga signal, I am using espvgax2 right now, and I am taking input through serial from another device, but that causes a lot of flickering, any ideas?

[hchunhui]

@grantwstaten Hi, I am not familiar with espvgax2. It looks like that espvgax2 uses a different approach to generate VGA signals, so the following may not be suitable for your situation.

I think the key to avoid flickering is to generate stable sync signals. For my project, I use a timer interrupt to generate HSYNC and VSYNC. The interrupt should be triggered every 32us. If the interrupt is delayed (for example Wifi interrupt has higher priority), the screen will flicker.

[gwstaten]

@hchunhui maybe I'll have more luck using your library, do you have any example code for using the library?

[hchunhui]

@grantwstaten Thank you! Currently there is no simpler example code. I think you can try espvgax. The library uses the same approach, has good documentation, and should be easier to use. If the screen still flickers, I have no better idea.

[gwstaten]

I tried espvgax at first and when I connected a serial port it was outputting bunches and bunches of stuff to it and wouldn't pick up on things that were being sent

…

On Fri, May 22, 2020, 10:18 AM hchunhui ***@***.***> wrote: @grantwstaten <https://github.com/grantwstaten> Thank you! Currently there is no simpler example code. I think you can try espvgax. The library uses the same approach, has good documentation, and should be easier to use. If the screen still flickers, I have no better idea. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#1 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ANGZQBADKY7L2OPZDLDJSYDRS2QURANCNFSM4E7W55VA> .

[hchunhui]

I remember esp8266 has two serial ports: GPIO1/3 and GPIO13/15, maybe you use the latter. The project use SPI port (GPIO13) to send VGA data, so the there is a conflict.

[gwstaten]

I'm not sure which one is used when you use a USB, I have been testing using that before I use it in the project it

…

On Fri, May 22, 2020, 11:09 AM hchunhui ***@***.***> wrote: I remember esp8266 has two serial ports: GPIO1/3 and GPIO13/15, maybe you use the latter. The project use SPI port (GPIO13) to send VGA data, so the there is a conflict. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#1 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ANGZQBHERJKMJ62AXWWSWFDRS2WUJANCNFSM4E7W55VA> .

[gwstaten]

Can I use both espvgax and serial on pins 1 and 3?

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On Fri, May 22, 2020, 11:16 AM Grant Staten ***@***.***> wrote: I'm not sure which one is used when you use a USB, I have been testing using that before I use it in the project it On Fri, May 22, 2020, 11:09 AM hchunhui ***@***.***> wrote: > I remember esp8266 has two serial ports: GPIO1/3 and GPIO13/15, maybe you > use the latter. The project use SPI port (GPIO13) to send VGA data, so the > there is a conflict. > > — > You are receiving this because you were mentioned. > Reply to this email directly, view it on GitHub > <#1 (comment)>, > or unsubscribe > <https://github.com/notifications/unsubscribe-auth/ANGZQBHERJKMJ62AXWWSWFDRS2WUJANCNFSM4E7W55VA> > . >

[gwstaten]

Apparently I can, but the flicker is there... How can I prioritize the library code over the serial code?

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On Fri, May 22, 2020, 11:31 AM Grant Staten ***@***.***> wrote: Can I use both espvgax and serial on pins 1 and 3? On Fri, May 22, 2020, 11:16 AM Grant Staten ***@***.***> wrote: > I'm not sure which one is used when you use a USB, I have been testing > using that before I use it in the project it > > On Fri, May 22, 2020, 11:09 AM hchunhui ***@***.***> wrote: > >> I remember esp8266 has two serial ports: GPIO1/3 and GPIO13/15, maybe >> you use the latter. The project use SPI port (GPIO13) to send VGA data, so >> the there is a conflict. >> >> — >> You are receiving this because you were mentioned. >> Reply to this email directly, view it on GitHub >> <#1 (comment)>, >> or unsubscribe >> <https://github.com/notifications/unsubscribe-auth/ANGZQBHERJKMJ62AXWWSWFDRS2WUJANCNFSM4E7W55VA> >> . >> >