for Megaswitch HD



Added support for the Audio-ADC board, which enables digitizing analog audio and outputting it to the HDMI transmitter (24-bit, 48Khz or 96Khz).

Sampling:   (Added)
Added the option to select the sound sampling frequency in the HDMI transmitter and ADC chip.
"48Khz" uses down-sampling through a divider by 2.
"96Khz" does not use down-sampling. 

Left ADC gain:   (Added)
Right ADC gain:   (Added)
Added the option for amplifying the input analog audio signal for the left and right channels.
"0dB" gain is disabled.  
"-12dB" gain reduced to minimum .
"+12dB" gain up to maximum . The ADC chip allows amplification up to +40dB, but this would involve digital amplification, whereas up to +12dB is only analog. 

Swap Channel:   (Added)
Added an option to swap the left and right channels for the HDMI transmitter.
"Disabled" The swap function is disabled.  
"Enabled" The swap function is enabled .



Timings:   (Added)
Added the option to choose between two custom timings for 1920x1080p resolution.
"0"  represents timings of version 21.0.0. These generate HDMI lines synchronously with 240p by multiplying them 5x. The duration of one HDMI frame is equivalent to that of a 240p console frame. This method is used in the line doubling algorithm. However, this resolution is not compatible with all TVs.
"1"  represents timings that also have an HDMI frame duration equivalent to that of a 240p console frame. However, HDMI lines are generated for a longer duration compared to 240p lines. This allowed the timings to approach the SMPTE 274M standard, though not completely (due to differences in pixel frequency). As a result, compatibility with TVs increased, but not with all of them. 


Inputlag:   (Added)
Displays the delay within the video buffer when it's in the "Single buffer" mode. When switching resolutions from 320x224 to 256x224, the VDP can briefly interrupt the 240p generation. In some cases, the VDP might shift the phase of 240p generation. With each resolution switch in 240p, input lag can accumulate. Therefore, in the "Single buffer" mode, the input lag is dynamic. And for a more precise understanding of the accumulated delay at any given time, I added a display of this value. The duration of the input lag is represented in terms of 240p lines. There are a total of 262 lines. This means the lag can range from 0 to 261 and constantly change with each new resolution. 


HInterpolation:   (Added)
This is horizontal smoothing that affects one subpixel of 1080p, situated at the junction between two original 240p pixels.



HDMI output:
Displays the current generated resolution.
"1080p" signifies 1920x1080p with custom timings.
"@60" or "@50" indicates a refresh rate of 60/50Hz. 

After changing the resolution (not available in this firmware version), you need to select "Apply"

Screen size:

Aspect ratio:
Allows selecting aspect ratio horizontally between "4:3" and "16:9"

Enables vertical image scaling using multiplication factors with fractional values. Ranges from "4x" to "5x". A factor of "4.834x" closely approximates displaying 224 original lines on 1080 visible HDMI lines. 


Output mode:
"Single buffer" is a HDMI generation mode without synchronization with the 240p console. This allows continuous HDMI generation even if the VDP is turned off, changes resolution, or shifts the 240p generation phase. This frequently occurs in UMK3 (switching between 320x224 and 256x224) or Sonic 2 (switching between 240p and 480i).  
"Zero delay" is a synchronized HDMI generation mode. Synchronization occurs either at the initial visible lines of 240p and 1080p, or at the final visible lines. This depends on the rate at which 1080p visible lines are generated. If they are generated faster than 240p lines, synchronization occurs at the lower lines. If 1080p is generated slower than 240p, HDMI synchronization takes place at the upper line. This approach achieves a zero delay. 

Advanced features:

Allows clipping of colored garbage frames around the image. On CRT televisions, the area around the image was not displayed. However, during upscaling, especially with an aspect ratio of 4:3 or when the height is less than 4.834x, these backgrounds become visible. Therefore, displaying them is optional. 

CRAM dots:
These are artifacts that appear on the hardware version of the VDP. They are usually visible in the lower part of the image or in the middle during palette cycling (such as water levels in Sonic). In the original, they cannot be disabled. However, the mod reconstructs some of the VDP's functions and is not affected by such artifacts. But I have added additional conditions for their occurrence. Therefore, the artifact is optional.


HDMI Color:
The original color depth is 4 bits per one of the RGB channels (12 bits in total). HDMI allows outputting 8 bits per channel (24 bits). Therefore, it's possible to distribute the 4-bit value to the 8-bit one in different ways, thus upscaling the color depth.
"Full RGB 0-255" is a linear distribution of the 4-bit value across an 8-bit number, ranging from 0 to 255.
"test1 0-244" is also a linear distribution of the 4-bit value across an 8-bit number, but ranging from 0 to 244.


Supports all regions and provides detailed information about the current VDP video mode. The HDMI frequency depends on the refresh rate. 

To invoke the OSD, you hold down the selected buttons on the gamepad. 

Gamepad test:
Can you check the functionality of the gamepad. 

Absolutely all settings will be set to default. 

Concise information about the board and links.