Just got it working.
Just got it working.
Here is a Atari 2600 Cart PCB. It is the basic 2K/4K EEPROM. I don’t have the PCB files uploaded yet but you can download the CAM files. This is free for anyone to use, sell, and/or distribute.
I will be uploading the PCB files in a week or so when I get back from my vacation. I use FreePCB. I will be uploading my custom footprint library as well so people can open the files.
The WS2801 is a 3-channel constant current LED drivers that is designed for controlling chains of RGB LEDs. The IC is controlled by a 2-wire serial control scheme that allows multiple WS2801 to be chained together. You can find the WS2801 in the link below. This demo code basically shifts out 24 bits (8bits per color) using a 2-wire protocol. This code only works for one WS2801. There is a object designed for multiple WS2801 already in the propeller OBEX. That design uses too many resources for use on my pinball machine so I wrote this to use as little resources as possible (no new cog).
The idea would be to have the WS2801 PWM a set of mosfets which would in turn be connected to the string of LEDs. This way you could light up a bunch of RGB LEDs without allot of CPU time taken from the Propeller. The Propeller only has to mess with the WS2801 when it needs to change the PWM signals.
I soldered on what parts I had on hand and got the DMD display working today. Will upload the code after I get all the modules soldered on.
Just finished the DMD (Dot Matrix Display) test for RESET_VECTOR. Since the Propeller is to slow to do the matrixing I am going to use a FPGA to do it. The propeller will send the data over a serial connection into a frame buffer on the FPGA. When all the data is on the FPGA the FPGA will update its matrixing buffer.
I have the Propeller to FPGA communication protocol written and tested as well. The Propeller loads the Data off the SD card and sends it serially to the FPGA.
This portable is designed using a vac formed case. It will be constructed out of ABS plastic over styrene for strength and texture.
Because this portable will use vac formed plastic I am able to make a much more ergonomic shaped case.
Project Unity is basically going to be a new PCB for the Atari 2600 that will feature a video mod, audio amp, power conversion circuity, and controls. This will enable a much smaller format for portables and make it easier to make a portable for beginners in the hobby.
I hope I got the connections right. This is the first time I have designed something this large. Videos mods are easy to separate the Digital and Analog components (resistor ladder separates them well). I should have added more ground planes on this but its a prototype so its mainly for testing purposes. The only thing I am worried about is the power converter (switching regulator type Ti PTN4050) might be a bit to close to the clock signal for the Atari but its buffered by a couple 100uF caps so it should be ok.
The board measures 4.65″ x 3.45″. Has built in power converters (to up a 3.7V Lithium Cell to 5V), audio amp, video mod, and controls for the left player. Stereo jack, right and left difficulty switches, black and white switch (some games use this as a control). Only thing it misses is the Right control port as Serial ports are dam huge.
Everything soldered in place. Some stuff needs to be replaced but its working!
Ok the board is going to need some revision. The video circuity needs to be placed on the other side of the board along with a page worth of issues. Good thing the prototype at least works. All these issues are just nitpicks of mine.
After the success of my first two portables decided to start shrinking the size of my portables to something that would be easier to carry around. For V3 of the NESp I am going to base it off a NOAC (Nintendo On A Chip) board. A NOAC is basically a chip that emulates how a real NES works. The advantages are that it reduces power consumptions of the portable and it makes it smaller. However NOAC’s are not 100% compatibly with every single game (about 3-5 games don’t work).
Make it as small as possible
Use a 3.5″ screen
Smaller footprint then the PSone 5″
Large enough to easily see whats going on
Minimum of 5 hours of life
Lithium battery 1600mAh
The NOAC is comprised of 3 boards. The board on the left is the A/V plugs and DC input. The middle board is where the NOAC is located and the right board is where the controllers are plugged in. The only board necessary is the middle board.
The total size should be around 6.5″x4″x2″ which is roughly half the size my previous portable (SNES V1) is.
Finished the design today. Turned out pretty close to what I wanted it to be. 6.5″x3.5″x2″
I finished the case. Turned out pretty good I think. Looks a lot like a wooden brick. The buttons and D-pad are done but I didn’t take a picture of those.
Here you can see the two input jacks. The one of the left will be headphones and the one on the right will be the recharge jack.
Finished hacking the NOAC and LCD screen today.
The controller board has to be removed so the screen will fit in the case. The board contains the inputs and other various controls for the LCD screen. These have to be soldered directly to the driver board for the screen. The board on the left is the controller board and the board in the clamps is the driver board.
The trim pots control the brightness, color, and contrast. Removing the control board reduced the overall thickness of the LCD screen from 1″ to 1/2″. The inputs and trim ports where connected directly to the driver board with 24AWG solid strand hook up wire. The driver board has convenient soldering pads for this.
To fix the LCD screen into the case I used some hotglue. After I install the controls and buttons I will fix the trim pots to the case.
The NOAC was attached to the case with hotglue and soldered to the LCD screen. Slowly starting to get somewhere with this portable.
Back with good news. I finished the portable and I am now testing it.
Well enough with the guts.
The case turned out much better then I had expected. At first I didn’t like how I rounded the corners but the more I play the portable the more I like them.
The power button here is epoxied to the top of a large tact switch.
I received a suggestion to make the D-pad out of 1 solid piece of wood. I will look into it the next time I build a case.
Since the portable is so small the controller boards took up all the space on the front panel so the speaker had to go here.
This volume slider is probably my favorite new feature of my design. Expect to see it in upcoming portables.
The one on the left is the headphone jack. It automatically switches the sound to the built in speaker off when you plug a headset in. The jack on the right is the charger. It also disconnects the battery from the main circuity when you charge the battery. The portable is unplayable when charging but it is safer when charging lithium batteries.
I really like these hex headed screws. They look much better then the normal stainless steel machine screws that I previously used.
Being the first portable I built with an AEIComp LCD screen I was very impressed with the quality of the screens. They are bright, clear, and sharp.
I am slowly refining my portable designs. In my next portable I am going to make the guts of the portable as streamlined as possible. Even though no one sees the insides it is just nice not to have a nest of wires to deal with.
Draws only .5A at 7.4V!