Waynetho
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Posts posted by Waynetho
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Upon reflection, I see that the DP4T switch option gives a more streamlined approach than my 74LS02 solution. The DP4T chip method only requires three wires and two pull-down resistors and no additional circuitry (74LS02). The NOR or OR gate solution makes the switch more logical in it's hookup but it requires more components to make it work.
Additionally, it will work with the board that is already in this thread rather than creating a new board with the logic circuitry.
I bow to a more elegant design.
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Using the NOR gates (or OR gates) will eliminate the need for the second pole on the switch, simplifying the wiring to the switch considerably. The OR and NOR will be inverted results (1234 vs 4321),
- One of the inputs of each OR or NOR gate will be connected together and connected to position #4.
- The other input for each OR or NOR gate will go to either position #3 or #2 respectively.
- Position #1 is "NC"
- The leads to #2, #3 and #4 switch positions should be pulled DOWN via suitable value of resistors (3.3K, 4.7K, etc)
- Output of one OR or NOR gate goes to A15 and the output of the other one goes to A14.
This means with four wires to the switch (three inputs and one +5v), one can switch between four separate OS's.
Edit: I forgot to mention that in my circuit design, the other four inputs for the other two gates are tied to ground so they aren't floating.
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I have a circuit (heretofore untested) that uses three pull-down resistors and two NOR gates from a 74LS02 TTL chip that will allow the use of a single pole 4-way switch (rotary or slide switch) for OS selection instead of the 2-bit binary switching. It uses a 4 to 2 encoder circuit with NOR gates. Position #1 is open (NC) because the three inputs on the encoder are pulled down. As a result, in position #1 pins A15/A14 on the eprom are set High/High. When switching to positions 2, 3 or 4, either A15/A14 are High/Low, Low/High or Low/Low.
I need to acquire an eprom programmer or at least the temporary use of one, before I can build the circuit and test it but I'm over 99% certain that it will work as designed.
I think it might be possible to nest the 74LS02 inside the socket area of the board above or one similar, along with the three resistors for the 4 to 2 encoder. No pull-up or pull-down resistors are needed for the eprom pins because the 74LS02 provides the distinct logic states needed by the pins.
Has anyone else considered something similar to eliminate the need for the pair of binary selector switches?
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Can someone clarify for me whether or not the Sophia rev.C DVI board outputs a 100% digital signal?
I thought I'd read somewhere, or heard in one of the videos about it, that the signal is 100% digital. I know the fact that it uses DVI doesn't necessarily mean it's all digital as DVI can pass analog, digital, or both, but I was really sure that it did output a 100% digital signal.
In another thread, someone told me to make certain the monitor or TV that I planned to use it on accepted a 15kHz signal on the DVI port, or on the HDMI port if I planned to use a DVI to HDMI converter. This made no sense to me if the signal was digital, so I thought I'd better research a little further before looking into purchasing.
Thanks.
YES - 100% digital. Some monitors are a bit finicky about the signal though, so a cheap monitor, dedicated to the Atari (or time-shared as a second display) is what I ended up choosing. I bought an AOC 20" monitor with HDMI input at a Micro Center store in Dallas TX USA for $65.00 (64.99) USD, +tx. Due to lack of a physical control to switch inputs, I chose to set it up as a second monitor in a DUAL MONITOR configuration on my PC. I'm receiving a VGA AB switch box today that I will use to turn off the second video source from my PC which will revert my PC to single video mode, leaving my Atari to take advantage of the second monitor's HDMI input, unfettered.
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I'm trying to get in touch with Simius to see if I can purchase one of his Sophia rev.C DVI boards, but I had a question about video inputs that are required from the monitor. Because of this thread, I assume it isn't as easy as plugging into a DVI port, or an HDMI port with a DVI to HDMI converter. Someone mentioned to me that I need to make certain the monitor is capable of accepting a 15kHz signal and that didn't make any sense to me. I know that's an issue with the analog signal when trying to connect an ST to a later VGA monitor, but I didn't think this was an issue with something like the Sophia. I thought I'd read that Sophia outputs a completely digital signal, so the horizontal frequency issue should be out the window, right?
Or am I completely missing the boat on something?
My HP s2031, although not liking the video signal, said the input signal was H: 62.8KHz and V: 60Hz. I still do not know exactly what the HP monitor didn't like about the signal since 62.8KHz is well within its supported horizontal frequencies.
And YES, it is an ALL DIGITAL signal but the monitor still requires a horizontal frequency otherwise as I understand it, you would have a straight vertical line instead of an image.
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Compatible monitor with HDMI port:
AOC E2070Sw +/? (NTSC works, PAL unknown)
One caveat, this monitor has no controls other than power so switching between the VGA and HDMI ports is a bit difficult. I have my PC's VGA going to the monitor through a VGA extension cable and I"m unplugging the extension to break the VGA so I can use the Atari. Conversely, the HDMI signal has to be cut before it will switch back to VGA.
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If you take the signals off the luma rail straight after the resistor ladder and from color signal it should be as close to the Gtia chip as possible for a purer signal.
I'm looking at The schematics over the next day or so and will see where best to put the lum and chroma connections for purest signal.
Obviously twisting the in and out pairs (separately) is best to reduce induced noise from other circuits on the motherboard. Right?
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If you are ok with s-video, you can take your signals from the board direct.
See here. This mod only needs a capacitor and resistor to perform this.
I see now that this mod uses the LUM/CHROM signals already existing on the board. Let me ask this, without the mod, will I see the trash visible in the images above (color distortion and jumping/flickering)? My cable just comes off of the existing CH and L pins on the AV jack and goes straight to the S-Vid connector.
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Update on my off-topic search for a scaler to resolve my monitor's issue with Sophia: The cheap Bytecc HDMI Scaler does NOT work. It doesn't even come on when in circuit, possibly because it's not a true HDMI signal but rather the DVI data moved to the right pins.
I'm going to try a cheap AOC monitor next, fingers crossed.
Magic Knight, is there any benefit to using board level S-video mod over the CHROMA/LUMA signals? Of course my outputs are polluted so if the board level signals are clean, that's a definite plus but I wonder if the mod actually duplicates circuitry that's already on the separated video on the board or if it's an improvement over the included signals.
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Okay, I understand...
Still willing to provide pictures if you want them (when I get home). Just figured you were thinking it might have been the work done to install the Sophia mod was responsible for the video issues.
That being said, if I choose to keep the RF mod, does anybody know if there's a place to get a good replacement RF for the 130XE, or perhaps a way to bypass the RF Mod and re-create the composite signal circuitry without it?
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See this post for pictures: http://atariage.com/forums/topic/220737-problem-with-atari-800xl/?p=2908506
220V variants are not known to be as problematic.
The only power supply that Atari made that was not black was the XL style rebuildable one, also visible in the pictures in that linked post...
The 600/800XL P/S that I have is the one in the lower left of that picture. I just associate the white one above that with the 65/130XE because the color matches.
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since it's been modded, pictures of how the mod is installed, and if you did the mod with or without chip defeat or removal...
The problems shown above in the composite and chroma/luma images were present before the Sophia mod was installed. They weren't present in 2001 after the SIO2PC was installed because that's what I used to load programs (exclusively) since I never bought a drive or disks when I got the 130 back then. All of my original 800XL and 400 equipment was either sold or given to my nephew in the late 80s or early 90s.
When you mention the chip defeat, are you referring to the Sophia mod or the SIO2PC? I'm not familiar with that. If you're referring to mods mentioned in my comments in another thread, those mods are not in this computer. They were part of my 800XL that I gave up about 30 years ago.
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So the Sofia mod is in the same machine?
Have you tried testing another Atari with your display in question, and another display with this machine?
How about to a real CRT instead of an LCD?
I'm suspecting this particular LCD display doesn't like the slightly off-spec video signal...
Yes, the Sophia is in the same machine. I added those pictures for reference even though I know there's an out of range error, since the image is crisp.
I've already been looking at options for getting Sophia to work with this monitor. It works with my Samsung 48" HDTV. I'm probably going to get an UP/DOWN-SCALER to pass the signal through.
When I go to the info screen on the monitor, it displays CURRENT: H=62.8KHz V=60Hz, RECOMMENDED: 1600x900, 60Hz
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Lastly, verify your power supply is still outputting a solid +5V. Hopefully it's not the ingot supply that will likely fry your computer.
Regarding the power supply, it's the black brick that's labeled for use on 600XL and 800XL. It's not a 130XE (bone colored) P/S.
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Yes to audio, no to broken wires. I ohm'd out each pin last night and they all have proper continuity.
One point of interest, I'm not running the top shield but I haven't done since I installed the SIO2PC mod in 2001. Any noise I would be getting as a result of unshielded circuitry should have been present 18 years ago.
I'm inclined to believe the RF MOD is borked thus causing the striped image on the RF and the composite. The video distortion on the chroma/luma is the only thing that's perplexing me. The fact that the DVI image is crystal clear with no distortion and such tells me that the GTIA and ANTIC are unlikely to be the cause as the video from a new circuit is perfect. If I pull the RF-MOD, I will automatically eliminate two issues (RF and composite issues) by default along with losing composite. If that clears up the chroma signal on the separated video remains to be seen.
The cable started out as a standard 6' shielded RCA cable (cut in half) and a 3' section from an S-Video cable, soldered to a 5-pin DIN plug, so there shouldn't be any issue with shielding of the cable.
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Lastly, verify your power supply is still outputting a solid +5V. Hopefully it's not the ingot supply that will likely fry your computer.
The PS is providing 5.12v with no load. From the axial capacitor near the cartridge socket, I get 4.98-5.02 VDC.
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what's your pinout on your s-video cable? Looks like a few of your pictures are from mismatches - ie composite going to luma (b/w vertical bars), + chroma (b/w bars with some colour), composite to luma + chroma (too much colour)
Reference: http://www.mixinc.net/atari/pinouts/monitor.htm
Double check your pinouts. Often the pre-made cables will have 4 RCA jacks (composite,luma,chroma,audio) or 1 svideo (luma+chroma) and 1 audio.
Maybe your using a very recent model TV that tries to auto detect composite from a single (Y input) on a shared use component input?
Lastly, verify your power supply is still outputting a solid +5V. Hopefully it's not the ingot supply that will likely fry your computer.
I wish I could blame the cable but I built the cable myself and it worked in 2001/2002.
I just pinned it out to make sure there wasn't some mistake that I didn't catch way back then. The pins on the cable (when looking at the pins, not the socket) are:
LUMA * * AUDIO
VID * * CHROMA
*
GND
The S-Video is ("=" is the key):
LUM * * CHROMA
GND * = * GND
Also the COMPOSITE VIDEO and AUDIO are correct on their respective RCA plugs, the outer ring is GND and the pin is the respective signal.
Also, the playback images were using the AV cable on my Kworld UB445-U2 USB ATSC tuner stick. SVid, Composite, etc. The RF when I tested it, looked similar to the composite as in vertical stripes and it was using the NTSC RF input on the same stick.
I have used other devices plugged into the TV stick as a control test to make sure the stick isn't to blame. They were fine. I booted my Raspberry Pi model B using the RCA video to the USB TV stick and the initial boot "color test" is near perfect with no striping.
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I purchased an Atari 130XE on Ebay back in 2001 and used it quite a bit for a couple of years until I upgraded my PC and no longer had a serial port and couldn't use APE as a file server.
It has been put up since 2002/3 and when I got it out recently to try out again, I discovered the video is trash. I didn't show the RF video but it looks like the composite photos only more blurry. Below are photos of the Pac-Man title screen and the boot screen in composite and s-video (custom cable using chroma and luma signals) and I have also included the same screens from my Sophia DVI mode for reference. Pardon the "Input out of range" box in the middle of the Sophia photos. My monitor doesn't like the signal.
Can someone give me suggestions on why my Composite and separated video look like crap? The chroma/luma (separated or S-Video) video jumps and displays wavy color distortions like RF interference but this wasn't present when I packed up the computer in the early 2000s. Prior to packing up, the composite was the video mode I used most and it looked good. Now it's vertical gray bars.
Could this all be due to the RF Modulator going south on me? I understand some signals (composite) come from the modulator but can that also inject color garbage into the CHROMA signal?
Boot screen using bad s-video (chroma/luma separated video) (custom cable)
Boot screen using bad Composite (should be blue but has gray bars)
Boot screen from Sophia DVI (monitor shows input out of range error)
Pac-man title using bad S-video/separated video
Pac-man title using bad composite video
Pac-man title using Sophia DVI (monitor doesn't like DVI signal)
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I just realized that I wasn't totally clear on my description of "Rom Smash". The reason the BASIC rom defeat and the cartridge images worked was that magical "loader" that was in the header of the dumped cartridge. The support software would ask one question, (DOS Needed?) and tailor the loader accordingly.
The program would then determine whether the cartridge was 8K or 16K (nevermind the ones that have larger bank-switched memory like those from OSS). It would save the loader for that cartridge and DOS requirements and add the cartridge dump to the file after.
When the loader started, it either said "INSERT DOS DISK and flip switch to 8K [*or "16K"] or just "Flip switch to 8K [*or "16K"]. The loader would be constantly checking the 8K and 16K high-byte for its inability to be changed (store, invert, read, replace if different than stored). Once the loader couldn't change the appropriate RAM position, it would start the load of the remainder of the file which was the cartridge dump. Since the BASIC rom defeat was also activated before the cartridge image is loaded, the RAM is available to hold the image.
Then anytime the CPU was trying to write to memory (ANYWHERE), the cartridge selects were active, hiding the RAM in those locations. When the CPU wasn't writing to RAM, the ram was available in the cartridge area.
The interesting thing is, the program relied on the ability to carefully plug in a cartridge (thus toggling the cartridge selects) WITHOUT locking up or rebooting the computer - and this worked most of the time on my 800XL and several others that I built the system for.
It's all coming back to me now...
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I'm not new to "invasive", although most of my mods back in the day were add-ons and they didn't require permanent modifications other than desoldering and replacing ram or socketing other chips.
If I recall correctly, the most invasive I got besides a ram upgrade was when I installed my cartridge booby-trap defeat (I called "Rom Smash"). It's been 34 years since that mod but I still have one in my collection.of junk and the schematic and drawings. I just don't have the custom program I wrote that dumped the cartridges to files with a loader though..
"Rom Smash" was a combination of two separate circuits that worked in tandem. It was a built-in BASIC defeat that required pin 11 on the PIA be lifted with one wire attached to the pin and another to the socket, and a circuit that activated either the 8K (cartridge pin 14) or 16K (cartidge pin A) chip select when the CPU went into a write cycle (cartridge pin R), if the switch was in 8K or 16K mode. This effectively hid memory under the cartridge when it was in danger of being corrupted by any booby-traps in the cartridge.
To this day I haven't cut a trace on any Atari.
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NVM. I just found the freezer mod by Bob Woolley (Is that you, Atari Bob?) It requires 74HC chips and trace interruptions (cuts) so not as simple as I thought it could be.
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Can the Antic pin 6 being pulled low work without the "Turbo Freezer" adapter being installed (assuming the "Freezer mod" is the same as the "Turbo Freezer" board I have seen online)?
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This is a big problem as well. I dont know of any tvs, monitors or even receivers that allow you to use a (digital) hdmi videosignal, and discarding its (non-existing) audiopart, and combine it with an analog audio input... i dont even think a scaler will allow this, not sure, maybe a professional one.
If you are using a pc monitor and dont have the need to route the atari through your home/multimedia devices, the only thing you can do is add some external speakers with built in amps and analog input. Like the video in the start topic of this thread. Or, if your tv has multiple hdmi inputs, use that for picture and use an analog input on the receiver (same principle). Probably the only solution for me as well... my receiver is the hub for all signals, but not for this one.
Or find some (pro) mixing device that has hdmi in and out that allows to convert and mix the audio into the hdmi output...
It's possible but the link I found for DVI+Audio to HDMI converter is a bit pricey at $225.00 USD. Maybe there are other active converters that take DVI-D +Audio and integrate it together to the HDMI.
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Am I the only one who gets an image from Sophia just fine, but the monitor displays an error over the screen until the OSD times out and then the screen goes to sleep?
I have an HP S2031 (NTSC). I get a white box in the middle of a perfect Atari screen that says:
Input out of range
Change settings to 1600 x 900 60Hz
If I go to monitor status it says:
Current settings: H=62.8KHz V=60Hz
Recommended settings: 1600x900 - 60Hz
WTF does 62.8KHz by 60Hz mean and why does the monitor display it but not like it? Before someone states the obvious, yes I know the horizontal frequency is 62.8 KHz and the vertical frequency is 60 Hz. I mean in the scheme of things, what does 62.8KHz x 60Hz mean as far as resolutions?
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DIY 4xOS Switch
in Atari 8-Bit Computers
Posted · Edited by Waynetho
Interesting side story about a conversation I had with Wes Newell in the mid '80's regarding my plans to make a triple OS board similar to his Ramrod XL. He told me it would be impossible to make a 3-OS board unless I could source the special three position switch (ON-ON-ON) that he used with his board.
I proved him wrong. I used a PULL-UP resistor for the CS pins on the first and third chips, and a PULL-DOWN resistor for the CS on the middle chip. I used a DPDT "Center-OFF" switch to GROUND either #1 or #3 chip's CS in their respective switch position, along with pulling the middle chip's CS "HIGH" when in either "ON" position. In the CENTER-OFF position, the board defaulted to the #2 chip active due to #1 and #3 being pulled HIGH and the #2 chip being pulled LOW by resistors. The switch used five wires (CS-1, CS-3, GND, and CS-2, +5V).
This was accomplished with a switch readily available from Radio Shack. For the record, I didn't mass-produce the board or even give it a name. I made one for my 800XL and I believe two more for friends, all hand-wired.
I wish we had 27512 chips and the mod discussed in this thread back then as the OS daughter board required three separate 16k OS chips.