Notice

This device does not lower VGA horizontal frequency from 31Khz to 15.7Khz, it is not a downscaler.

For safety, do not connect two devices simultaneously to the VGA and SCART inputs, only use one of them.

What is it?

MonochromeRGB is MonochromeVGA evolution, a project to enjoy the charm of those monochrome monitors of the time but in the current video systems, those with VGA or SCART inputs. Where this product is most enjoyed is in CRT monitors, where the feeling of an old monitor is much more realistic.

Why did you make it?

After the good acceptance that MonochromeVGA has had among the Tindie community, I have decided to go one step further and bring the experience of monochrome mode to TVs with SCART input, with the possibility of accepting SCART or VGA signals at 15.7Khz in the horizontal frequency.

Although it can be used with various retro systems, PCs or Raspberry PI, one of the projects that I think could benefit the most would be the MiSTer, an FPGA for which multiple cores of consoles, computers and arcade machines have been developed.

What makes it special?

Like the other project I have developed, called MonochromeVGA, you can select green, amber or B&W as monochromatic color, among others. Change color to monochrome or vice versa easily. And what's more, you can adjust the intensity of each color in 4 levels and of course, also deactivate it.

MonochromeRGB is composed of two PCBs and allows several possible configurations of use:

• VGA to VGA passively, without the need for any power supply, as MonochromeVGA

• SCART to SCART, also without the need for any power supply

• VGA at 15.7Khz horizontal frequency to SCART with automatic 4:3 <-> 16:9 aspect change for compatible TVs, being necessary 5V power supply via microUSB or from the VGA connector itself. This is possible thanks to the implementation of another project, called The ultimate VGA to SCART adapter

• If the VGA input has 5V on pin 9, an external power supply would not be necessary on the MicroUSB connector

Aditional details

The SCART output can present a slight noise in the image, although some TVs could filter it completely and not be visible, I have also decided not to apply any type of filter on this output, because the noise is very slight and gives a certain retro look, nice and very nostalgic in my opinion.

The magnificent design of the 3D case is the work of Agustin Gallego, who, as with MonochromeVGA, I must congratulate him on this great work.

In some FPGA system like the case of the ZXUno it is not currently compatible because it only offers the mixed of both signals (CSync) in HSync for PAL mode at 15.7Khz ... so this conversion does not make sense, it could be used directly as SCART to SCART in this case, since the VGA2SCART module loses meaning in this case. MiSTer for example, however, offers the possibility of HSync and VSync on the output even at 15.7Khz, with CSync being an optional feature.

By the way, in this first version the signals of the 4:3 <-> 16:9 changeover switch are inverted, something of little importance since at a functional level it is correct.

In addition to its monochromatic ability to generate different colors, with some RGB combinations in color mode it is also possible to make interesting palette changes in certain retro systems, as can be seen in one of the images, although this is not mentioned in the introductory video shown below and produced by Invertigo. YouTube allows you to activate subtitles and translate them into English without problems, which is more than acceptable: