GBS 8200/8220 CFW Project

[NoAffinity]

@CatMachete do you have another clock gen? I usually buy them in a 3 pack because quality isnt always guaranteed. I'd start with confirming your wiring and no bridged connections, and if everything checks out then replace the clock gen. Lastly, make sure you're on the firmware from Rama's github. Actually you could start with the firmware before moving to hardware diagnosis/replacement.

[SGGG2]

How's the quality when used as a straight transcoder to VGA or component?

[Solidzera]

Which video amplifier chip does Ali's Retroscaler GBS-C is using? Does anyone know?

I am asking because there is this brazilian shop that is using THS7376IPWR claiming it has better colors and definitiion on the image.
<https://gamescare.com.br/produto/gbs-co ... mi-nativo/>

I just want to know which one has better image, the Ali's Retroscaler GBS or this brazilian GBS

Thanks everyone!

PS: this is the brazilian GBS in action <https://youtu.be/Ptb_HrzRV_A>

[Josh128]

Which video amplifier chip does Ali's Retroscaler GBS-C is using? Does anyone know?

I am asking because there is this brazilian shop that is using THS7376IPWR claiming it has better colors and definitiion on the image.
<https://gamescare.com.br/produto/gbs-co ... mi-nativo/>

I just want to know which one has better image, the Ali's Retroscaler GBS or this brazilian GBS

Thanks everyone!

PS: this is the brazilian GBS in action <https://youtu.be/Ptb_HrzRV_A>

This looks to be just a standard GBS with a custom board slapped on top for inputs. Where do you see it claiming to use a THS7376IPWR? I doubt someone produced a different GBS board. I would imagine the colors are no different than standard GBS, which seems to over emphasize blues.

[Solidzera]

Which video amplifier chip does Ali's Retroscaler GBS-C is using? Does anyone know?

I am asking because there is this brazilian shop that is using THS7376IPWR claiming it has better colors and definitiion on the image.
<https://gamescare.com.br/produto/gbs-co ... mi-nativo/>

I just want to know which one has better image, the Ali's Retroscaler GBS or this brazilian GBS

Thanks everyone!

PS: this is the brazilian GBS in action <https://youtu.be/Ptb_HrzRV_A>

This looks to be just a standard GBS with a custom board slapped on top for inputs. Where do you see it claiming to use a THS7376IPWR? I doubt someone produced a different GBS board. I would imagine the colors are no different than standard GBS, which seems to over emphasize blues.

The creator the man on the vídeo said it in portuguese language on the same video at 3:47. "Encoder 7376"

[jd213]

Crap, I wonder if I got a bad clockgen as well, I'm not getting a picture unless I disable the external clockgen. Have only tested it on an LCD monitor with a generic VGA to HDMI adapter, though, will try my PC CRT later.

Colors look fine from over component from a PS2, but with RGBS from a Genesis, black is tinted blue, similar to this user's problem (except he was apparently getting tint with component):
viewtopic.php?p=1517685&sid=1c0a85300d3 ... 8#p1517685

[kitty666cats]

I apparently posted this on a thread about non-scaling VGA to HDMI converters years ago:

https://www.amazon.com/Ableconn-VGA2HDM ... B00WAIX5S4

...decided to check the link and see why I was curious about it (mentioned below) and noticed a particular review on it. One that sounds great!

======

"ive tried many with my gbs-c gbs-control gbs-8200 and they all lose sync with an og xbox using component. With this one i have never had one signal drop or blackout! I would recommend!"

=====

So, looks like my intuition from years ago (looking up the Silicon Image/Lattice chipset inside led me to the link) was good! Anyone who is looking for a reliable VGA to HDMI on the output of their GBSC unit ought to give this a try. I, personally, have used an OSSC as passthrough for my GBSC... lol. I have a plasma that sucks ass over VGA, as well as not accepting 1080p (not super surprising, but like I said: looks like ass in genera w/ resolutions it DOES acceptl) but looks amazing over HDMI. But using a OSSC as a VGA to HDMI is very very excessive, unless you already have one lying around.

Sooooo, yeah - this one is a keeper! I'll link the .PDF of the chipset I linked in the old-ass thread - it literally says it accepts 240p on the input (not super relevant, but def a good sign)

First, here's a nice excerpt -

Spoiler

Excerpt:

1. General Description
The Lattice Semiconductor SiI8784 device is a high
quality, multi-format analog video decoder and
processor with an integrated dual-mode High
Definition Multimedia Interface (HDMI®)/Mobil
High-definition Link (MHL®) transmitter. A
microcontroller is integrated to reduce the system Bill
Of Materials (BOM) cost.
The SiI8784 device supports worldwide PAL, NTSC and
SECAM standards, YPbPr video signals up to 1080p @
60 Hz resolution, and RGB graphics signals from VGA
to UXGA resolutions. It also supports the SCART
interface with Fast Blanking and the D-Terminal.
This device contains a Time Base Correction (TBC)
module, a de-interlacer with a post-processor engine,
and a VBI decoder. For content protected analog
videos, HDCP will automatically be enabled on the
HDMI or MHL output.
1.1. Features
1.1.1. Analog Video Front-end
 Four 10-bit Analog to Digital Convertors (ADC)
sampling up to 170 MHz
 Flexible input multiplexers to support composite,
component, VGA, SCART with Fast Blanking and
D-Terminal interfaces
 Supports cable plug-in detection and active video
signal detection
1.1.2. Multi-format Video Decoder
 Automatic format detection
 Supports NTSC, PAL, and SECAM standards of
composite input with adaptive comb filter
 Supports 240p, 480i/p, 576i/p, 720p, 1080i/p
component video
 Supports RGB graphics from VGA to UXGA
 Supports Macrovision Type I, II, III copy protection
detection
 Supports multi-standard VBI decoding: Teletext,
WSS, VPS, CC, CGMS, and V-CHIP
1.1.3. Video Processing
 Time Base Correction
 De-interlacer with Edge Smoothing
 Automatic Phase/Position Detection
1.1.4. HDMI/MHL Transmitter
 Selectable HDMI/MHL Dual-mode
 Compliant with HDMI 1.4b and MHL 2.1
specifications
 HDMI output up to 1080p @ 60 Hz or
UXGA @ 60 Hz resolution
 MHL output up to 1080p @ 60 Hz resolution
 HDCP 1.4
 Audio insertion with I2
S/ SPDIF input
 VBI data forwarding over HDMI/MHL

...

Figure 3.7. Transmitter Video Data Processing Path Embedded Sync Decoder
The input processor can create DE, HSYNC, and VSYNC signals using the start of active video (SAV) and end of active
video (EAV) codes within the ITU-R BT.656-format video stream.
3.4.2.1. Data Enable Generator
The transmitter includes logic to construct a DE signal from the incoming HSYNC, VSYNC, and clock. Registers are
programmed to enable the DE signal to define the size of the active display region.
3.4.2.2. Combiner
The clock, data, and sync information is combined into a complete set of signals required for TMDS encoding. From
here, the signals are manipulated by the register-selected video processing blocks.
3.4.2.3. 422 to 444 Up-sampler
Chrominance up-sampling and down-sampling increase or decrease the number of chrominance samples in each line of
video. Up-sampling doubles the number of chrominance samples in each line, converting 4:2:2 sampled video to 4:4:4
sampled video.
3.4.2.4. 444 to 422 Decimation
Decimation reduces the number of chrominance samples in each line by half, converting 4:4:4 sampled video to 4:2:2
video.
3.4.2.5. Color Space Converters (CSC)
Two color space converters (CSCs) (YCbCr to RGB and RGB to YCbCr) are available to interface to the many video
formats supplied by A/V processors and to provide full DVI backward compatibility. The CSC can be adjusted to perform
standard-definition conversions (ITU.601) or high-definition conversions (ITU.709) by setting the appropriate registers.
RGB to YCbCr
The RGBYCbCr color space converter can convert from video data RGB to standard definition or to high definition
YCbCr formats. The HDMI AVI packet defines the color space of the incoming video.

...I'd just look at that, personally. But here's the .PDF of the chipset, too...

https://www.latticesemi.com/-/media/Lat ... t_id=51619

[twix]

First of all I wanted to thank all of the developers and supporters of this project! Such an amazing piece of tech!
It allowed me to get crisp image from my recently obtained Atari 520 STm using 2018 GBS 8200, although I'm having some issues:
1. External clock generator prevents GBS from working at all. I disconnected it and seemingly not having any issues with image upscaling.
2. I'm using an old LED Samsung TV, which has kinds of inputs I need (VGA, composite, component, RF) and a 4:3 800x600 display. With GBSC's 480p output the image is shifted to the right and I have to move and scale image to make it show in the center of the screen.
3. I stored output settings to a profile, but it does not seem to be selected/applied properly on each input blink or mode switch, so I have to manually select other preset, load it and then reload a working preset from #2.

How can modify output modes list to remove almost all 16:9 resolutions and add a proper 4:3 VGA? As I understand, I will have to modify not just the firmware sketch, but a WebUI as well. Can somebody point me to a detailed documentation/instructions of doing that?

Thank you!

[Dailenth]

Greetings forum, I saw some people are concerned about the Chinese prebuilt GBS-C RetroScaler and I'd like to share my experience regards to updating the firmware.

It appears there's a few Chinese prebuilds, the few that I know of are:

GBS-C ODV
BitFunx GBS-C Pro

And the TZT/HamGeek/etc variants

I did some research, stumbled upon this Russian youtube video while I was looking how to update the Chinese default firmware, because it was two years out of date compared to the official ramapcsx2 repository, he briefly mentions that the official firmware can work on any spinoff of GBSC. In my case it did .

However, it was not without any issues. I had configured my Arduino IDE, loaded libraries, verified the sourcecode and was ready to upload via USB. Upon plugging the ESP8266 displayed the blue indicator and worked only for 5 seconds.

Next I tried powering it with the 5V2A While flashing, a potentially very stupid idea as it was not mentioned in the user manual. It could have made sense because these prebuilts have one unified PCB board, the ESP8266 is incorporated in the whole circuit, it's not just soldered

So theoretically just a USB would not have worked, it didn't power anything else not even the OLED display. I can't confirm that you need a DC input to complete the flashing.

I tried to flash at first with the official guide using the binary (bin file) and NodeMCU PyFlasher, it didn't work either.

What ended up successfully is flashing using OTA(Over the air) using the WiFi local website, then linking it with my Arduino IDE. Now I do have the latest version, I can tell because I have color correction options and the ability to delete presets, something the Chinese scaler didn't had when it shipped.

The only problem with these open source forks is that they're never maintained, they release version 1.0 and just abandon the sourcecode. Thankfully the official firmware is fully compatible as expected, though you need to compile the code yourself, and follow the steps carefully.

[Bassa-Bassa]

The only problem with these open source forks is that they're never maintained, they release version 1.0 and just abandon the sourcecode. Thankfully the official firmware is fully compatible as expected, though you need to compile the code yourself, and follow the steps carefully.

Thanks for sharing. Isn't any of these prebuilt units sold with a properly updated code in 2024?