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Bryan

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  1. Bryan

    Atari 8-bit Game Scene

    By Bryan,

    I've been watching videos of upcoming game releases on various platforms and I've noticed that sometimes developers get in a rut and we see far too many of the same types of games and not a lot of innovation. I guess what bothers me most is hearing of some new game coming out and then finding out it fits the following template:

    1. Amazing full-color RastaConverter title screen. Probably a bigger executable than the game itself.
    2. Amazing title screen music.
    3. Pressing Start dumps you into some ho-hum puzzle game or some other simple concept that doesn't live up to the extravagant intro.

    I realize we have tools to make impressive images and music now, but they make a simple game look worse by setting the standard too high. What I really want to see on the A8 is innovation. Either bring something to the A8 library that's been missing or come up with an experience no one's seen before.

    I look at what's going on in the (admittedly larger) C64 community and it's pretty incredible what people are attempting there. People are writing impressive game engines for the Spectrum too even though they know they'll always look kinda mangy in the end. Of course, they can do stuff we can't do and we can do stuff they can't do so let's find more of those things. Then we can slap 70 color title screens on them.

    And oh yeah, why do I find SID music to be so irritating after a while? Somehow I find myself suffering from sawtooth overload after just a few minutes.
  2. Bryan
    Recommended board: Plug-In (if 4050 soldered in)

    The 5200 may either have soldered or socketed 4050. This will affect the procedure somewhat so we'll start with instructions for a soldered in 4050:

    Position the main PCB with the cartridge slot toward the back.

    Soldered-in 4050:

    1. Solder the 16-pin socket on top of the 4050. It is only necessary to solder pins 1, 3, 5, 7, 8, 9 and 11. Soldering pin 16 is probably a good idea as well just to secure all corners of the socket. With a reasonably small iron tip, you should be able to work between the 4050 and the Antic chip behind it.
    2. Connect a wire to the front pad of R17. This is the rightmost 1K resistor in front of the 4050. This will be the Color In wire.
    3. Make sure the jumpers are configured for the 5200 and install the UAV in the socket with the green terminal toward the back.
    4. Connect the Color-In wire to terminal 1 (the terminal closest to the right back corner). Make sure the wire is clamped in securely.
    5. Attach your video cables to the UAV. The remaining terminals (2-6) are Ground, Chroma, Luma, Composite, and a 2nd Ground.

    Socketed 4050:
    I am currently revising this section as the 4050 is necessary to retain the reset hardware and the jumper method isn't reliable enough.

    Removing the 4050 to plug in the UAV will disable the RF video. If this isn't a problem, then follow these steps:

    1. Remove the 4050.
    2. Connect a wire to the front pad of R17. This is the rightmost 1K resistor in front of the 4050. This will be the Color In wire.
    3. Make sure the jumpers are configured for the 5200 and install the UAV in the socket with the green terminal toward the back.
    4. Connect the Color-In wire to terminal 1 (the terminal closest to the right back corner). Make sure the wire is clamped in securely.
    5. Solder a jumper across the back pads of R2 and R3 (only do this if the 4050 is removed!)
    6. Attach your video cables to the UAV. The remaining terminals (2-6) are Ground, Chroma, Luma, Composite, and a 2nd Ground.

    If you wish to retain RF video, then you'll need to keep the 4050. However, soldering a socket on top of the 4050 will raise the UAV up too high to replace the shielding which is necessary for decent RF performance. For this reason, it is preferable to get a Kit and build the UAV according to This post and then follow the instructions above (skipping step 5).

    Installing an Audio Companion board:


    1. Locate C37 and solder the Audio Companion board across its leads with ground (G) toward the front. Apply the soldering iron to both the capacitor lead and the large pads at the bottom of the board while applying solder until they flow together. This will provide power and hold the AC in place.
    2. Solder a wire from input iA (the first pad at the top from the back) to the back pad of R50 (1K). This resistor is just inside the shield area in front of where the AC is now installed.
    3. Connect the audio out wire to the last pad on the Audio Companion marked out. If you're using a coaxial wire, you can connect ground to the back pad of the capacitor in front of C37 (C51) or any other nearby grounded spot like the exposed shield strip.

    Carefully check your work against the pictures before powering the system. Route cables carefully out of the shielding during reassembly.

  3. Bryan
    Recommended board: Basic.

    The 7800 uses a 74LS08 to combine the video signals from TIA and Maria and discrete wires will be needed to get the combined signals to the UAV.

    -^Cro§Bow^- has done some excellent videos and an install guide.



    UAV_Installation_A7800.pdf

    Installing an Audio Companion board:

    The Audio Companion board will mix the 7800's TIA audio with audio from a cartridge at the appropriate levels without requiring any modifications to the existing circuit. RF audio will continue to work as before.

    1. Locate C16 and solder the Audio Companion board across its leads with ground (G) toward the front. Apply the soldering iron to both the capacitor lead and the large pads at the bottom of the board while applying solder until they flow together. This will provide power and hold the AC in place.
    2. Solder a wire from input iA (the first pad at the top from the back) to the front pad of R6 (18K). This is the resistor to the left of the RF audio choke on NTSC 7800's.
    3. Solder a wire from input iC (the third pad at the top from the back) to the front pad of R5 (6.8K). This is the resistor next to R6 on NTSC 7800's.
    4. Connect the audio out wire to the last pad on the Audio Companion marked out. If you're using a coaxial wire, you can connect ground to the front pad of the unused spot for C18.

    Carefully check your work against the pictures before powering the system. Route cables carefully out of the shielding during reassembly.
  4. Bryan
    The Audio Companion board is designed to be a simple way to add high quality sound to Atari consoles and computers lacking a sound output (predominantly the 2600, 5200, 7800, 400). It can also be used in any system as an audio mixer. For example, a stereo Pokey setup can be mixed to a mono output without affecting the separation of the 2 stereo channels. Two boards can be installed to provide multiple different outputs as well.

    The most common question is, "What makes this better than the audio modifications currently being done?" There are three main advantages:

    1. The AC board installs very simply without cutting or removing anything on the board. The AC board gets its power from being soldered across a power decoupling capacitor and its high impedance inputs don't disturb the existing audio circuits. The board can be removed at any time without the need for any repairs.

    2. The AC board uses an op-amp to provide a buffered line-level signal. This gives the output a consistent quality when driving various amplifiers and cables. Picking audio off without a buffer can give inconsistent results.

    3. The AC board has 4 additive mixing inputs designed to preserve the system's intended audio functions. This means the AC will play 7800 games with cartridge audio intact. The AC will provide the 400 with audio that includes the cassette audio track. Other sources can be mixed in as well if desired.

    Installation is simple. Find a power supply decoupling capacitor near the audio circuits or power supply input (these caps will usually be 0.1µF and may be marked '104' to denote this value). Determine which side has 5V with a multimeter and solder the board across the cap observing the polarity markings. Run wires from the AC inputs (A-D) to the appropriate signal points for your system and another wire from the output to your audio jack. Then run a ground wire back to the AC board ground pad or a nearby ground point on the system board.

    There are 4 inputs on the Audio Companion. Using the correct input is important for proper level matching (input iD is marked on the board for reference).

    A - Input for Pokey or TIA audio.
    B - Second input for Pokey or TIA audio.
    C - 7800 cartridge audio input.
    D - 400 SIO audio input.

    There is one audio out pad (marked out) that can drive one or two audio jacks.

    On the back of the board is a gain pad that can be cut to provide a 3dB output boost if desired.

    Here are pictures of the board and schematic:
  5. Bryan
    Recommended board: Kit (or let me know if you want the Kit pre-assembled for the Jr.)

    Instructions are for the NTSC 3-chip version. I don't have access to a unicorn/1-chip or PAL version. Please contact me if you're willing to help expand these instructions. If the C101688 unicorn chip is the same as Warner's 'Jan' chip, then it isn't compatible with UAV.

    This is one of the more difficult installs. There just isn't much room in the 2600jr and removing the 4050 isn't an option as it's used by the reset circuit. Soldering and desoldering are required. The Jr's case seems to be very brittle so use caution when taking the screws out so the internal posts don't snap off. Lift the left side of the top case first so you can unplug the flex cable going to the switches. The board is held in by snap levers on the left and right edge. Again, be careful not to break these. Once the board is out, you can straighten the tabs on the bottom of the shield and remove it.

    My Jr. didn't have anything holding the regulator down which means it isn't making use of the large cooling pad on the PCB. I'd advise soldering the tab down or putting a screw through the board.

    To install the UAV, you're going to need to remove the 4050 or run wires to it and mount it outside the shield (which can be done with a Basic Board). These instructions deal with installing it under the shield.

    1. Using the components in the Kit, install the configuration jumpers and the round socket pins. Do not install the green terminal.
    2. Desolder the 4050. This can most easily done by clipping the legs off and then clearing the pad holes individually. Hold on to the 4050 as we'll be using it later (Fig. 1, 2).
    3. The internal shielding is required for a good RF picture. If you don't plan on using the RF output, you can omit the shielding and install the UAV in a socket as shown in Fig. 3. Otherwise, solder the UAV directly into the board as shown in Fig. 4.
    4. Install the 4050 on the bottom of the board (Fig. 5). This part is tricky. Trim the leads flush with the bottom of the IC and place in the middle of the UAV pins. The 4050 must be upside down, and pin 1 must be oriented toward the middle of the PCB. It may be necessary to bend the UAV pins slightly outwards. Solder each pin carefully and make sure nothing will contact the bottom shield (if used).
    5. Lift the back leg of R54 and solder the Color pick-up wire to the exposed pad. Solder the other end to the Color In pad on the UAV (Fig. 6).
    6. If the RF jack isn't going to be used, it can be re-purposed as a Composite or Audio jack. To do this, lift the right side of R19 and solder the desired signal to the exposed pad (Fig. 6).
    7. Set the jumpers as shown in Figure 6.
    8. Install desired AV jacks and connect the wires to the appropriate output pads on the UAV (Composite, Chroma, Luma, Ground).

    Installing an Audio Companion board:

    1. Locate C12 and solder the Audio Companion board across its leads with ground (G) toward the back (Fig. 7).
    2. Solder a wire from input iA (the first one toward the front) to the front pad of R34 (I used the connected via just in front of it in Figure 8 ).
    3. Connect the audio out wire to the last pad on the Audio Companion marked out. If you wish to use the RF jack for audio, see step 6 above.
    4. Connect audio ground to the ground pad on the Audio Companion, or any nearby ground point on the PCB. This isn't needed if you use the RF jack.

    Carefully check your work against the pictures before powering the system. Route cables carefully out of the shielding during reassembly.
  6. Bryan

    Install - UAV & AC in the 400

    By Bryan,

    revised Jan 2, 2018
    Recommended board: Plug-In

    The 400 has socketed chips including the 4050. The easiest installation is to put the UAV in the 4050 socket, but if you want to keep the RF output, you'll need to solder the socket on top of the 4050 and then mount the UAV on top of it. These instructions should work for NTSC and PAL systems.

    Position the main PCB with the CPU board slot toward the back.

    1. Connect a wire to the left side of C187. This is Color-In.
    2. recommended: Solder the 16-pin socket on top of the 4050 (best done with the 4050 removed).
    2. Make sure the UAV jumpers are set for the 400 and install it in the socket. The green terminal should be facing away from you.
    3. Put the Color-In wire in the right-most terminal (terminal 1 when facing the terminal openings).
    4. Attach your video cables to the UAV. The remaining terminals (R to L) are Ground, Chroma, Luma, Composite, and a 2nd Ground.

    Installing an Audio Companion board:

    1. Locate C182. The AC board will go on the back side of the leads.
    2. Line up the corresponding pads on the AC board and solder it to C182's leads so that it stands upright (the power pads are available on both sides of the board and are marked + and G).
    3. Attach a wire for Pokey audio to the front end of R160.
    4. Attach the other end to the first input pad ('iA' directly above the + power pad).
    5. Attach a wire for SIO audio to the right side of R170.
    6. Attach the other end to the last input pad ('iD', the 4th pad from the left).
    7. Attach your audio out wire to the output pad (directly above the G power pad).
    8. Attach audio ground to the ground pad on the back side of the UAV.

    Carefully check your work against the pictures before powering the system. Route cables carefully out of the shielding during reassembly.
  7. Bryan

    Introduction

    By Bryan,

    I know it's been hard to find UAV specifics in a hurry so I'm making a blog to put the most pertinent information in one place. Over the next few weeks I'll be putting up install documentation and links to the best info in the forums.

    Now, a little bit about UAV itself. For a long time I've wanted a video upgrade for the A8 computers that would straighten out Atari's missteps with the factory circuits and also address an issue within GTIA itself. I also wanted an upgrade that wouldn't require me to do extensive butchering on the board. I planned to make it conform to the appropriate video specifications since "good enough" video was beginning to cause compatibility problems on modern TV's.

    When I began looking at the output of various Atari systems on an oscilloscope (always remember to load the output with 75 ohms first!), I discovered that the levels were all over the place and color carrier rarely resembled a sine wave. Some of the existing attempts to fix the video were resulting in a cleaner picture, but were causing the levels to be even more out of spec. I decided that my new upgrade needed to produce a perfect color carrier, needed to find the best overall balance between brightness and color saturation, and needed its own regulator to reduce the amount of system noise present in output. This last one has proven to be quite a challenge since ultimately, everything in that little box shares a common supply.

    There was one other issue that I designed UAV to address, and that's luminance skew. GTIA's 4 luminance pins are not skew matched or directly clocked and don't always change in tandem. The result is noise on the pixel boundaries with the worst case being the shade 7 to 8 transition in GTIA mode 9. To address this, UAV has a circuit to monitor the luminance pins to detect a change in shade, then a small delay before the new state is latched and displayed. This delay is controlled by the blue potentiometer on Rev C and D boards (Rev A and B were a little different in operation and never left the lab). This results in a razor sharp pixel edge and the adjustment also has the side benefit of changing the artifact colors. Adjusting for something close to the XE's Red/Blue scheme is probably the best aligned setting, though.

    The next step was design a board that would work in any Atari computer or video game system having a 4050 video buffer chip and fit into as many places as possible. This resulted in a tiny SMD board that I originally assembled completely by hand. Now I order them mostly assembled after staying up night after night trying to fill Rev C orders. For systems without a 4050, it's still fairly easy to solder the board in with wires to the appropriate points on the board. It's always been a design goal to not disrupt the original video circuits if possible. This is primarily so that the upgrade is reversible, but also so that the RF output can be retained if desired.

    I'm going to be posting install information created by myself and others here soon, and thanks to everyone so far who has purchased the board and waded through page after page of forum threads to find the relevant instructions. And, even more thanks to those who posted their own instructions and helped others with their questions. It has not gone unnoticed.
  8. Bryan
    Recommended board: Plug-In

    The 6-switch 2600 usually has socketed chips, but a soldered in 4050. This isn't a problem though because there's enough room in the shield for a top-mounted socket and Plug-In board, and the 4050 needs to stay anyway as it is used to buffer the joystick triggers (later 2600 revisions don't do this). These instructions should work for PAL systems as well, but the pictures won't exactly match and be sure to skip step 8.

    Position the main PCB with the cartridge slot toward the back.

    1. Connect a wire to the left side of R231. This will be power to the UAV. The 4050's power pin is connected to an inline resistor and won't properly power the UAV.
    2. Connect a wire to the right side of R212. This is Color-In.
    3. Cut pin 1 off the socket. The will break the power connection. If this pin is not removed, it will be necessary to cut the 5V pad on the UAV.
    4. Solder the socket onto the 4050. It'll be tight working around the other components, but it's only necessary to solder the pins used by the UAV (3, 5, 8, 11 and 14).
    5. Make sure the UAV jumpers are set for the 2600 and install it in the socket. The green terminal should be facing you.
    6. Solder the power wire to the 5V pad (left side of the pad if the pad is cut - this is the side next to the UAV logo).
    7. Put the Color-In wire in the leftmost terminal.
    8. (NTSC only) Pull out the TIA (C010444) and bend pin 6 out of the socket. If the TIA is soldered in, then lift one end of R213 out of the board.
    9. Attach your video cables to the UAV. The remaining terminals are Ground, Chroma, Luma, Composite, and a 2nd Ground.

    Installing an Audio Companion board:

    Flip the board over with the cartridge slot still toward the back.

    NTSC:
    1. Locate the power and ground pads shown.
    2. Line up the corresponding pads on the AC board and solder it in place standing upright (the power pads are on both sides of the board and are marked + and G).
    3. Attach a wire from TIA pin 12 to the 1st input pad (directly above the + power pad).
    4. Attach your audio out wire to the output pad (directly above the G power pad).
    5. Attach audio ground to the ground trace near the AC board.

    PAL:
    Coming Soon!

    Carefully check your work against the pictures before powering the system. Route cables carefully out of the shielding during reassembly.
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