+ 
+
+
+
+
+GBS Control
+an alternative firmware for Tvia Trueview5725 based upscalers / video converter boards.
+ Read the documentation +
+ an alternative firmware for Tvia Trueview5725 based upscalers / video converter boards.
+ Read the documentation +
buy me a coffee.
Cheers! :)
-
diff --git a/Wiki/Arcade-Boards.md b/Wiki/Arcade-Boards.md
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+---
+sort: 15
+---
+
+# Arcade Boards notes
+
+User @tracedebrake posted some comments regarding the use of arcade boards with the GBS scaler (or any other scaler).
+I've copied them here, so that arcade machine users are aware of what to look out for.
+
+> Hello @xuserv & @ramapcsx2!
+>
+> Might I ask, @xuserv, if you have done every recommanded modifications to your GBS 8200, including soldeging a 100ohm resistor from CSYNC to ground & setting all 3 RGB potentiometer to the minimum (left)?
+>
+> I'm asking this because normally, most arcade SuperGuns will not properly adjust your RGBS signals to be 75 ohms & 0.7v peak-to-peak levels compatible. Arcade video signals have the same timing as NTSC video but the electrical properties are different to a standard TV/video monitor. It's analog signals with TTL level amplitude (3-5 Vpp) while regular gaming consoles are made for home use so they output at 0.7v pk-to-pk for a 75ohms load (your tv) . Arcade monitors also have a very high inputs impedance to match those TTL voltage levels (1k-10k ohms).
+>
+> This is why the GBS8200 has a high input resistor (1k) on CSYNC; it is made for arcade use by connecting your JAMMA harness directly to the RGBS pins.
+>
+> By doing the recommanded mods (100ohm resistor + adjusting your pots total left (or removing them)), what you are actually doing is modifing your GBS8200 to be console compatible. If you want to use a SuperGun with a fully modified GBS8200, you need to make sure 1st that your SuperGun properly adjust the RGBS signals to TV levels using a buffer/driver, such as the HAS v3.1
+>
+> This is exactly why some people blown their expensive OSSC or Framemeister; their SuperGun wasn't properly adjusting video signals.
+
+
+> The main issues with arcade boards are this:
+>
+> - they never ever been designed to be played outside their cabinet
+>
+> - there's was no video standard. Full-scale arcades manufacturers had not only the joy to create their own board from ground up but also the one of choosing the right monitor and fine tune it accordingly.
+>
+> The JAMMA standard that came at the end of the 80s/early 90s was created to allow arcade center operators to use old cabinets again & again only by changing the game board, controls and cabinet side arts/marquees. But still, since no standard was ever made for video, arcade monitors had those adjustments pots mounted either at the back of the monitor or on an external harness like this one to render the monitor ''compatible'' with the new board. That was a pain to adjust right and sometimes the adjustment was buggy at best. Even the JAMMA standard itself wasn't respected for long: some games were designed to use more buttons than what the standard allowed (exemple Street Figther 2) by using dormant pins on the JAMMA connector or by adding new connectors on their boards; see kick harness.
+>
+> All SuperGuns try to adapt that video chaos for what a 75ohm TV needs but it doesn't mean that they are doing it right. There is mostly 3 types of SuperGuns video designs around:
+>
+> - Fixed resistor value: You can't just slap some resistors on the RGBS lines and attenuate them that way by hoping to create a voltage divider. RGBS output levels from arcade boards varies too much from a board to an other to use fixed values. Avoid at all cost (exemple: the horrible Vogatek.)
+>
+> - Potentiometers: Better than having fixed values but same as above since you don't know for sure what you're doing. Having nice colors on your TV doesn't mean that you aren't flooding your AV equipment protection diodes, if they have any. This solution will mostly kill your AV (TV, scaler) as well in the long run. To me it's an avoid at all cost as well. (exemple: the RetroElectronik Pro gamer)
+>
+> - Impedance matching: very high impedance, video-bandwidth amplifiers/buffers ARE NECESSARY to prevent RGB distorsion and provide a steady impedance match for 75 ohms AV inputs. Same with the sync but it needs to be buffered, attenuated and impedance matched as well. This is the only way to go. (exemple: the current HAS 3.1 (almost impossible to get), the future Sentinel and the open-source DIY Thibaut Varènes design)
+
+A small reiteration regarding the "RetroElectronik Pro" as referenced above - By user @cglmrfreeman
+>I was using gbs-control directly with the RetroElectronik Pro Supergun and had a lot of noise in the black areas, as well as dark rolling waves across the screen when used with an HDMI converter. These flaws didn't appear using a VGA CRT monitor but I decided to do some testing anyway. Attaching the harness from the GBS unit directly to a JAMMA fingerboard resulted in significant improvements and no noise that I could make out.
+>
+>As the above states, there was no video standard for arcade boards, and JAMMA is nice, but if you can bypass your supergun, such as/specifically the RetroElectronik Pro, and connect directly into the GBS, I highly recommend that route.
\ No newline at end of file
diff --git a/Wiki/Build-the-Hardware.md b/Wiki/Build-the-Hardware.md
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+---
+sort: 2
+---
+
+## Intro
+Gbs-control is a replacement firmware for GBS8200 upscaler boards.
+It runs on the popular ESP8266 microcontroller and uses the Arduino plattform.
+
+GBS8200 upscalers can be bought on Ebay, at prices around $20.
+Ebay also has ESP8266 microcontroller boards for about $4.
+The ones called "Wemos D1" or "NodeMCU" work well and are recommended.
+
+## Basic Install
+You need the GBS upscaler, an ESP8266 board, a bit of cabling and a jumper or wire link for disabling the onboard processor, so that the ESP8266 can take over.
+Power for the ESP8266 can be provided by, for example:
+- using the power supply that powers the GBS > into the ESP8266 boards "Vin" (recommended, white connector next to power input)
+- using the GBS regulated Vcc (3.3V) > into the ESP8266 boards "3.3V" input (not recommended, but photo below shows this)
+
+Connect the ESP8266 board ground to a convenient ground point on the GBS.
+
+Connect the two I2C bus wires (GBS side: SDA and SCL) to the ESP8266 pins of the same name.
+ESP8266 boards do not have standardized pin names, but they follow some naming rules.
+- most boards label SDA and SCL directly
+- if they are not named (Wemos D1 Mini and many others): SCL is "D1", SDA is "D2"
+- if unsure, see if you can find your ESP8266 board [here](https://randomnerdtutorials.com/esp8266-pinout-reference-gpios/)
+- GBS side SDA goes to ESP8266 side SDA, same for SCL
+
+
+
+
+
+
+
+- Use a jumper to bridge the 2 pins below the first programming port (see picture above)
+### Connect DebugPin
+To enable automatic image position and timing adjustment, the ESP8266 needs to measure some timings.
+Carefully solder a wire from the pictured DebugPin to:
+- Wemos D1 / NodeMCU pin "D6"
+- some boards label this pin "D12" or "MISO"
+
+## Software setup
+Next, the ESP8266 needs to be programmed. Head over to the [software setup](./Software-Setup.html) page.
+
+## Troubleshooting
+
+### No Picture
+- Are SDA / SCL reversed? It's safe to reverse them and try again.
+- The debug pin does not have to be connected for gbscontrol to work at a basic level.
+- Forgot to install the jumper that disables the GBS original controller?
+- ~100 Ohm resistor to ground on Sync-in is installed?
+- when using a sync stripper: Is the LM1881 source voltage `5V`?
+
+
+
+```tip
+### To Debug Issues
+The Arduino IDE serial monitor shows debug information at `115200` baud.
+If your ESP8266 is connected to a computer via USB, you can access this serial monitor to find out more about the issue.
+In the Arduino IDE, you need to select an ESP8266 board that matches your hardware (if unsure, select "LOLIN(WEMOS) D1 R2 & mini").
+```
+
+
diff --git a/Wiki/ESP8266-Board-Adapter.md b/Wiki/ESP8266-Board-Adapter.md
new file mode 100644
index 00000000..a9e8c6a5
--- /dev/null
+++ b/Wiki/ESP8266-Board-Adapter.md
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+---
+sort: 6
+---
+# ESP8266 adapter
+
+```warning
+The adapter method places the ESP8266 very close to the TiVo5725 scaler chip, which exposes it to electromagnetic interference.
+As a result, the ESP8266 can have issues with its WiFi, resulting in limited access to the web interface.
+As such, I don't recommend using this adapter method.
+Instead, place the ESP8266 module right next to the GBS 8200 board, near the I2C connection headers.
+```
+
+## Old Article
+
+### Overview
+This is a method of mating a GBS board with a common ESP8266 development board, using a socket to attach to the original MCU.
+It provides all the required signals for the ESP8266 to take over control of the scaler.
+
+
+
+
+
+
+
+### Grinding down stand-offs
+
+
+
+
+
+
+
+### Inner socket surface has to be flat and even
+
+
+
+
+
+
+
+### Signal Locations
+
+
+
+
+
+
+
+### Mating Adapter with ESP8266 Dev Board
+
+
+
+
+
+
diff --git a/Wiki/GBS-8200-Variants.md b/Wiki/GBS-8200-Variants.md
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+++ b/Wiki/GBS-8200-Variants.md
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+---
+sort: 3
+---
+
+# GBS Variations
+## Yellow Button "V5.0" or "2017"
+Those newer GBS-8200 boards have an LDO oscillation problem.
+It works, but there will be a lot of noise in the picture.
+The easy fix is to remove one SMD capacitor, circled in red.
+
+
+
+```tip
+A better fix would be to replace this capacitor with an electrolytic of 22uF to 47uF.
+```
+
+
+
+
+
+
+
+
+[Background](http://www.ti.com/product/LM1117/datasheet/application_and_implementation#snos4127440)
+The chosen SMD capacitor on these boards has far too little capacitance (120nF measured) AND has very little ESR. It causes the LDO to permanently oscillate at around 20Mhz. There is an electrolytic capacitor further down the line that is sufficient for stable operation of the LDO.
+
+## Original GBS-8220
+
+Same LDO oscillation problem, but here it is limited to setups that use a power supply of > 5.0V.
+I get wild oscillation at 7.6V from a common PSOne supply.
+The same C11 removal fix works here as well.
+
+
+
+
+
+
+
+These variants also use a special video driver for the VGA output.
+The driver IC has a charge pump that it uses to generate negative voltage.
+This would be a useful feature for driving YPbPr signals, but here they just seem to dump the current onto the ground plane (from what I can tell at least).
+That charge pump is generating noise however, and since no ferrite bead is used at location R58, a noise pattern easily develops in the image.
+With a bead installed and some extra SMD capacitors, the image is fine again.
+
+
+
+
+
+
\ No newline at end of file
diff --git a/Wiki/Hardware-Mod-Library.md b/Wiki/Hardware-Mod-Library.md
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+++ b/Wiki/Hardware-Mod-Library.md
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+---
+sort: 7
+---
+
+# Hardware Mods Library
+
+This page lists all of the known modifications which people have attempted on the GBS82XX series boards, what they do, and if they should be performed or not.
+Note that in most cases, gbscontrol will work without any of these modifications.
+
+|Key| |
+|---|---|
+| ! | Essential |
+| O | Optional / Recommended |
+| X | Not needed / Deprecated |
+
+|Mod Description | _GBS8220_|_GBS8200_ |_GBS8200(2017)_| Effect/Issue Fixed by Mod |
+|----------------|----------|---------|---------------|---------------------------|
+|Add 100ohm resistor across sync and ground for RGBs input | ! | ! | ! | Corrects sync level for 75 Ohm sources (such as game consoles) |
+|Replace R34 with 75 Ohm resistor | O |O |O | Permanent 75 Ohm termination, instead of the mod above |
+|Remove C11, optionally replace with 22uF (6.3V to 16V) electrolytic cap | O |O |O | [Stabilizes 1.8V LDO, removes noise from image](./GBS-8200-Variants.html) |
+|Remove the 3 RGB potentiometers, replace with direct link | O | O | O | [Improves Colors](./RGB-Potentiometers.html) |
+|Add 10uf / 22uf ceramic SMD capacitors in parallel to stock ones (x4) C23, C41(alternative: C43), C42, C48 | O |O |O | [Provide local charge reservoir to help power supply bypassing. May reduce noise and waves in the image](./Power-supply-bypass-capacitors.html) |
+|Add a Sync Stripper circuit to RGBs input | O |O |O | Try this if sync is never quite stable |
+|Replace R58 with 120 Ohm ferrite bead | O |X |X | For GBS8220 (2 output version); decouples charge pump |
+|Add 100n cap between R59 and R58 | O |X |X | For GBS8220 (2 output version); decouples charge pump |
+|Replace C33 and C35 with 1nf (1000pf) SMD capacitors (0605/0805 50V C0G) | X |X |X | [Deprecated Sync fix](./Sync-on-Green-Capacitor-Replacements.html) |
+|Foil tape over digital signal lines | X |X |X | This was fixed in software (SDRAM delays) |
+|Replace L1 L2 L3 with 220R 100v ferrite beads | X |X |X | Not recommended until testing has concluded |
diff --git a/Wiki/Inputs.-SCART-adapter,-optional-sync-stripper.md b/Wiki/Inputs.-SCART-adapter,-optional-sync-stripper.md
new file mode 100644
index 00000000..478d6e6e
--- /dev/null
+++ b/Wiki/Inputs.-SCART-adapter,-optional-sync-stripper.md
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+---
+sort: 8
+---
+
+# SCART RGB to VGA adapter
+
+If you want to build an adapter, here is some good inspiration: https://tomdalby.com/other/gbs8200.html Use the "GBS-8200 SCART Circuit v2" picture as a guide and ignore the LM1881 chip, just connect the wires from the 8 pin JST HX connector to the female SCART socket then add the 100 Ohm resistor (if needed, see below for the details).
+
+The ArcadeForge Sync Strike is a solution that will work, if you don't want to build an adapter yourself.
+http://arcadeforge.net/Scaler-and-Strike-Devices/Sync-Strike::15.html?language=en
+
+
+
+```note
+Every GBS board comes with ~500 Ohm termination on the sync input. This termination is meant for (PC) VGA and most arcade boards.
+
+Csync from consoles should be fine without additional termination but the input may not behave well with other kinds of sync.
+
+If you want to use the RGBS input for regular video-level sync sources, the GBS requires one additional 100 Ohm resistor connected to ground from the sync input.