ESP32 + VS23S040 for greatly improved Component Video quality?

DigicoolThings

I really like the idea of the Basic Engine, but for me the Composite Video only output of the VS23S010 is a bit of a show stopper.

Unfortunately, Composite Video has very poor image quality and cross-color artifacting, especially on modern TV’s, as compared to a component video signal like S-Video (Luma + Chroma) or even full RGB or YPbPr component video.

So much so, that I modify my old retro Composite Video only game consoles for S-Video or other Component Video output, to allow enjoying the original 80’s graphics on modern screens.

Researching further, I see that the newer (and same US$6 priced) VS23S040 now has 4 Video DAC’s instead of 1, allowing it to also support Component Video output! ?

So my question is: Have you considered an updated design based on ESP32 + VS23S040, instead of the existing ESP8266 + VS23S010?

In addition to allowing much improved quality Component Video, there would also be added capability / possibilities with the ESP32’s dual cores etc.

... just thinking out loud. But otherwise, keep up the inspiring and awesome work! ?

uli

Thanks for your interest. This approach has been suggested by other people before; this is the answer I sent them:

An ESP32/VS23S040 combo, OTOH, would be a definite improvement. Using
the additional features of the 040 is not as straightforward as it
sounds, though. The 040 is really just four 010s glued together, each
producing its own video signal and only having access to its own 128k
bank of memory; it is therefore not possible to blit blocks of memory
from one 128k bank to another. RGB (or component, or S-Video) output
requires distributing graphics data over three (or two) VS23 cores, so
two or three times as much data has to be pushed over a single SPI
bus, which is already a bottleneck with the 010. Having one core of
the ESP32 dedicated to updating the video might make up for that (and
might even allow for wireless operation, due to the much less severe
real-time requirements), but that remains to be proven.

What I'm currently investigating as a path forward is to replace the whole hardware (MCU, video and I/O) with an FPGA, which provide surprisingly high performance/price ratios by now (~3,50 for an XC6SLX16 on AliExpress).

The clock speeds achievable are lower than with ASIC SoCs such as the ESP*, but the technology enables us to add features that nobody is ever going to provide in a low-end MCU, such as VGA, a (proper) USB HID host, game pad controller interfaces, more capable video etc. Add a 50-cent SDRAM for an arse-ton of memory and a similarly priced SPI flash for the FPGA config and firmware, and you have yourself a system.

I'm using this board for experimenting:
https://www.aliexpress.com/item/Latest-Xilinx-spartan6-XC6SLX16-Core-Board-Xilinx-spartan-6-FPGA-development-board-with-32MB-SDRAM-Micron/32828884647.html
And this SoC core:
https://github.com/f32c/f32c/

Note that this is very much in development, and I might not be able to work on it as much as I would like, so don't hold your breath.

uli

On a more practical note, there are several ways to tweak the video output of the BASIC Engine that can improve the image quality on a particular display. The most useful one to me is the luminance low-pass filter; enable it using CONFIG 3,1 and clear the screen. Another one is to choose a different default screen mode and/or font. See the manual for details: https://basicengine.org/manual.html#_config

davegardnerisme

I had to try a few composite --> HDMI adapters to find one that worked well. I would love the updated version though so +1 to this!

Marty

Hmm, good point, with those composite->something_else adapters. I have some in the drawers so I will give it a try.

RetepV

Just speculating, didn't actually have a look yet, but I think that replacing the ESP8266 with an ESP32 would already bring big improvements. For one, the ESP32 has more GPIO pins, which would allow the use of the VS23S010's 8-bit parallel mode without having to drop the joystick (and I think there are enough GPIOs for two joysticks). Secondly, the ESP32 is already more powerful and has more memory, while only about 2 dollars more to the BOM.

About picture quality. If it's really that important, it should be possible to get an improvement by separating the luminance and chrominance already on the board, and sending them to the monitor as y/c. As the separator would be on-board and close to the composite out of the VS23S010, the interference would be minimal, and I expect the picture to be better. Only issue: you would need a monitor with an y/c input. Don't know how common that is anymore. And I don't really think it's worth the trouble anyway. There are single-chip solutions. But it's the chip plus some 25 capacitors and resistors.