I/O Board

[danialbi]

Hi I am new to Atari forum
My focus is on ATARI800 and Amiga cores; apparently I only need the additional SDCARD (for ATARI800) feature, not the full I/O set

I have a couple of questions:
Can you suggest a SDCARD only solution that I can buy? Maybe just a PCB and mount the SDCARD connector?
Is it really a FAN required? Or an heatsink? I think the DE10 comes without

Thanks

[danialbi]

@mpattonm:
The 'blue combo' looks neat and fanless
Is the fan required at all?
How can I buy the 'blue combo'? price/delivery?
Thanks

[danialbi]

@Sorgelig:
beginner's question: I see the picture of I/O board at the beginning of thread; I see that you need to use SDRAM vertical version:
Is there any speed limitation?
Where I can get the 2 boards as in picture?
Thanks

[THaase]

Have a look to the
Local Sellers Thread

[BlockABoots]

Can some explain what the revisions of this I/O board changed?

I can get a version 5.3 but i know theres now the 5.5 boards out but not sure whats change and different?

[kinox51]

Can some explain what the revisions of this I/O board changed?

I can get a version 5.3 but i know theres now the 5.5 boards out but not sure whats change and different?

Hey BlockABoots, you can look into the "HW Installation instruction"-thread. In the .pdf-File are the differences mentioned.
http://www.atari-forum.com/viewtopic.php?f=117&t=34473

[BlockABoots]

Can some explain what the revisions of this I/O board changed?

I can get a version 5.3 but i know theres now the 5.5 boards out but not sure whats change and different?

Hey BlockABoots, you can look into the "HW Installation instruction"-thread. In the .pdf-File are the differences mentioned.
http://www.atari-forum.com/viewtopic.php?f=117&t=34473

Thanks

[atmn]

Got a question regarding the I/O board.
Assembled one and get it to work, Im very pleased.

Was about to try the VGA port, it worked well on my monitor. got a 640x480 out.

Isnt it possible to get a 15kHz signal to be able to connect to a old tube-tv, maybe get RGB and composite out? Or isnt it compatible at all on that area?

[Sorgelig]

Got a question regarding the I/O board.
Assembled one and get it to work, Im very pleased.

Was about to try the VGA port, it worked well on my monitor. got a 640x480 out.

Isnt it possible to get a 15kHz signal to be able to connect to a old tube-tv, maybe get RGB and composite out? Or isnt it compatible at all on that area?

Sometimes i don't want to reply to such questions. It's really pointless as 15KHz is supported on VGA output from the day 1. With VGA->SCART and VGA->Component cables it can be connected to TV.
It's really a wasting time and drawing unneeded attention because you just got the board and start to bombing the questions without trying to use it a little and understand the features first.

[warham]

I/O and RTC board supports if anyone wants them.

https://www.thingiverse.com/thing:3193029

[JimDrew]

Sorgelig,

I was looking over the v5.5 I/O board and noticed that you connected pin 10 of GPIO 1 to ground. That pin is normally GPIO_1[9] PIN_ AH 27. Is there a reason you connected it to ground?

[Sorgelig]

Sorgelig,

I was looking over the v5.5 I/O board and noticed that you connected pin 10 of GPIO 1 to ground. That pin is normally GPIO_1[9] PIN_ AH 27. Is there a reason you connected it to ground?

Yes. It tells to cores to enable VGA output.

[JimDrew]

Yes. It tells to cores to enable VGA output.

So, if you have an I/O board plugged in it outputs to both HDMI and VGA at that point, and only HDMI when there is no I/O board? The reason I am asking is the VGA doesn't work properly on any of my setups with the v5.5 or earlier I/O boards. When I boot the DE-10 I only get the MiSTer menu on the HDMI display. If I load any of the memory test cores then I see the display on both the HDMI and VGA displays, and at that point I can press F12 and load a different core. That is not possible in VGA mode when you first boot it. Also, Donkey Kong, Bagman, and several other cores I tried do not support the VGA output. This could be just a timing issue, but I am using a very common DELL 15" 31KHz PC monitor that is VGA only input.

[Sorgelig]

If this pin is grounded all my cores output video to VGA connector. If this pin is not grounded then all VGA signals in Hi-Z mode.

VGA connector doesn't exactly mean VGA timings. Basically it's analog video with whatever timings provided by cores. In most cases timings are NOT compatible with VGA. You need very special monitor supporting 15KHz and VSync as low as 48Hz.
With scandoubler enabled the cores output double hsync frequencies ~31KHz, but VSync remains the same as original (50Hz for PAL cores).

That's why HDMI is the main output of MiSTer.

[JimDrew]

Ok, so the VGA output is strictly 15Khz? Why do the memory test cores work with a 31KHz monitor? I have several monitors that do support 15KHz (for the Amiga), so I can try those. Also, how close if your R2R ladder for the VGA proper colors? It's not perfectly linear based on the resistors you used, but I wonder if it is worth the added expense to make it perfectly linear - or if you adjust the colors in the cores to compensate for this?

[JimDrew]

Sorgelig,

Please take a look at SW4 in your schematic for v5.5 I/O board (probably other versions are the same as well). You have the connections 4 and 6 swapped compared to the PCB and the data sheet for the switch.

It could be that your PCB part for this switch has the pins labeled like a standard IC:

1 2 3
6 5 4

The data sheet shows the pins as:

1 2 3
4 5 6

Also, it seems from the data sheet that the switch would have to be rotated 180 degrees from how you have it on the PCB for the plastic switch post to be sticking out past the edge of the board. I guess it should work either way.

[Sorgelig]

Ok, so the VGA output is strictly 15Khz?

You read it wrong. I've said that output frequency depends on core. Usually core can output both 15KHz and 31KHz depending on scandoubler option. 31KHz is not the only thing required for VGA compatibility. VGA also requires the vertical frequency to be at least 60Hz while many cores provide 50Hz or even 48Hz - so most VGA monitors won't work. That's why i've started MiSTer project. I couldn't agree that FPGA board must be used with special VGA monitor supporting non-standard frequencies and couldn't be used with random modern TV.
VGA connector is just connector - doesn't mean VGA compatible resolutions/frequencies. Usually core outputs video format which original retro system provided. Output format is fully controlled by FPGA core.

Also, how close if your R2R ladder for the VGA proper colors? It's not perfectly linear based on the resistors you used, but I wonder if it is worth the added expense to make it perfectly linear - or if you adjust the colors in the cores to compensate for this?

Color resistors are not strictly correct for high precision, but enough for hobbyist project. VGA strictly speaking is for debugging purpose while main video output is HDMI. VGA is 18bit while HDMI is 24bit. So, full color systems like Minimig will have some banding on VGA regardless how R2R is correct. R2R should provide linear voltage on the output and cores don't compensate it. So, if you will provide better linearity then it will be better. You also need to compensate FPGA output resistivity if you want good linearity.

Please take a look at SW4 in your schematic for v5.5 I/O board (probably other versions are the same as well). You have the connections 4 and 6 swapped compared to the PCB and the data sheet for the switch.

These switches are not standardized as ICs, so different manufacturers may have different pinout while physically they look and work the same. So, just follow the PCB footprint and schematics - it works correctly.

[JimDrew]

Where is the "scan doubler" option? I don't see anything in the menu that allows changing the frequency.

As for SW4 I was just going by the pinout of the data sheet for the switch you listed in the BOM. The schematic does not match the PCB layout for the part specified in the BOM. I just thought you should be aware of it.

[Sorgelig]

Schematic and PCB has been made for switch i've bought in local store. It had no name. Much later compatible switch has been found online and recommended in BOM.
There is no relation schematic to specific switch in BOM. You buy the switch and solder to PCB - you don't need to look into its datasheet at all.
In schematic 2 groups are shown in the same default positions, so you can refer to schematic and use the switch you like.

Where is the "scan doubler" option? I don't see anything in the menu that allows changing the frequency.

Most cores have Scandoubler FX option. Does the name "scandoubler" gives some hint?
For permanent scandoubler there is an option in MiSTer.ini file.

[jft]

Color resistors are not strictly correct for high precision, but enough for hobbyist project. VGA strictly speaking is for debugging purpose while main video output is HDMI. VGA is 18bit while HDMI is 24bit.

I wonder if anyone is looking at options for more accurate analog output for this project. I understand several folks interested in this project (myself included) would be very interested in high quality analog output for CRTs. Perhaps another IO board version that utilizes another cheap FPGA (thinking of Tim W's RGB boards for NES and Atari 2600) could accomplish this.

Sorgelig, not asking you take this task on (you are busy enough as it is and everyone appreciates your work on this project), but hypothetically - given your knowledge of the DE10 - do you think the DE10 is capable of more accurate analog output in the above scenario?

Maybe someone is willing to investigate

[Sorgelig]

More accurate values probably will require DAC IC.
99% of cores output not more than 4 bits per color component. Actually color fidelity wasn't a strong point of original emulated system. What current analog output provided by MiSTer is already much higher quality than it was originally.

So before to talk about improvement you need to understand what is the actual room for improvement. As i've told you 99% cores (including NES, Atari 2600,800,5200, etc) won't be improved even if you will add very high quality VGA DAC.

[jft]

Thank you Sorgelig for your insight and explanation. For now it seems more than adequate.
I imagine as the project progresses and cores appear for more advanced systems (which natively support 24-bit video - seems only Minimig at the moment) something like a DAC IC based solution will be more worthwhile for someone to develop.

[JimDrew]

Most cores have Scandoubler FX option. Does the name "scandoubler" gives some hint?

Sure, I guess I have not come across any core so far with this option.

[jft]

May be a dumb question...
So I'm doing a very small run of I/O boards ( < 10, I have some mostly built, just waiting on some parts), and I see several connectors/components listed as "DNI" in the diagram. I see several board makers listing "fully populated" boards - are we defining "fully populated" as "all components, MINUS the ones labeled DNI?," or "everything is installed including ones listed as DNI." There are some components (external button and LED pin headers for example) I may leave them optional (installed only when requested).

I ask because I want to ensure the I/O boards are fully usable by whomever ends up with them - and my soldering skills outweigh my electric engineering skills .

BTW having a lot of fun with the YPbPr output of the I/O board on my Sony CRT. After receiving some components just this morning, I completed one board "enough" to enable this output. Looks great so far

[Sorgelig]

DNI components should left unpopulated - they usually not required by most users. They are there if some users will really need it. Board without DNI components is considered fully populated.