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  1. A little bit of an update to this thread. 🙂 I was successful in connecting the Arduino Uno directly to the Atari joystick port(no opto-couplers) and getting the Star Raiders game to respond to the 'fake' joystick input from the Arduino. The sketch is clunky and slower than I'd like. But it is working. Both the Arduino and the Atari 800XL seem no worse for wear. Now to refine the whole process to a finished project. 🙂
  2. Hence the reason for the optocouplers. Isolate both the Atari and the ATmega328 board from each other as far as the data signals are concerned.
  3. Okay I think I see how the arduino is buffered from the joystick ports. Would the following schematic accurately describe the proper connection between the Atari joystick ports and the arduino? It's part of a stand alone ATMega 328P circuit getting power from the ports, not a development board.
  4. Looking over your blog post there, I had a bit of trouble making out the handwritten diagram for the optocouplers. On the transistor side you tied all the emitters together, but to what. I can't quite make out the word. 🙂
  5. I'm not. Digital pins 0 and 1 are the TX/RX pins. Digital pins 2 and up reference the rest of Port D (PD2 - PD7)
  6. I've heard that about Arduino Sketch, but for this small a project in the beginning learning phase of the whole environment, I wanted to use the training wheels that Arduino provided. Once I got some experience under my belt I felt I could then 'grow up' into the full blown C or C++ language usage. Baby steps I know. I'll take this info and try not to get to bloodied trying to translate it/understand it. 🤕 Thank you. 🙂
  7. Clear as mud. Here's what I think I see. You are using pure C or C++ not the tamer Arduino Sketch code and what looks like bitwise comparison or something like that. Way beyond my comprehension level at this point with the Arduino. I still need training wheels. 😧 But I'll try to translate it back to something that I am familiar enough with to understand what is happening. 😕 Okay let's start with the function that seems equivalent to the setup() function in Arduino Sketch code. I get that this seems to be setting PortB's pin direction, but what is it setting it too?
  8. I realize there are probably as many ways of doing this as there are people. And that nearly infinite way of writing code is where the confusion reigns when someone like me tries to understand it. But let me try. void setup() { // Set Uno pins 2-6 (UP/DOWN/LEFT/RIGHT/FIRE Joystick) off turnJPinsOFF(); } loop() { //Test Fire button operation pinMode(6, OUPUT); digitalWrite(6, HIGH); delay(1000); turnJPinsOFF(); } void turnJPinsOFF() { // Set Uno pins 2-6 (UP/DOWN/LEFT/RIGHT/FIRE Joystick) off for (int pinNumber = 2; pinNumber < 7; pinNumber++) { pinMode(pinNumber, INPUT_PULLUP); digitalWrite(pinNumber, LOW); } }
  9. So my understanding is actually reversed? Hmmm..... So I have the joystick port pins connected to the specific UNO pins 2-5(UP/DOWN/LEFT/RIGHT) and 6(FIRE). I would need to set those to pinMode(Input) and DigitalWrite(x, High) in setup to simulate a joystick at rest. Then as the Fire button is pressed or the joystick is moved to the various cardinal points, I would use DigitalWrite(x, Low)?
  10. I'm playing with a fairly small project at this time. Learning about Arduino and the Atmega328PB. Right now I have learned how to read the original Atari joystick CX40 via an Arduino Uno. That didn't seem to hard. The next logical step is to emulate that joystick via an Uno connected to the joystick port of an Atari 800XL. This is where I am running into a bit of a road block. 🤔 As I understand it the Atari provides a voltage on the UP/DOWN/LEFT/RIGHT/FIRE pins and when the joystick is moved to close one of the pin circuit, it presents a high to the PIA port. I'm not quite certain how to emulate that in code for the Uno. Does someone have an example of that they've verified works?
  11. Repeat AtariAge or the Internet hiccuped.
  12. A 2764 is 8K. Perfect for Atari Basic. I used 800XL/130XE OS as an example. Sorry if I confused you. Trying to use 2732A is possible with the adapter on the RD burner, but is dependent on the eprom. By that I don't necessarily mean the brand. You are trying to burn over 30 year old eproms with unknown number of erasures and reprogramming before you got them. Unfortunately there is no way to definitively say what will work or won't beyond matching the pinout and programming voltage and speed (faster is better) necessary. Make sure you are manually setting the memory range 0000 - 0FFF for 2732A and try the slow burning speed to see if it makes any difference. You can only try each eprom individually. And to make it even more fun, the same eprom that worked the last time, will suddenly die now. That's the reality of 30+ year old eproms. If your TI866 can read and burn the 2732A and 2532A, then by all means use it. Idiosyncrasies abound between eprom burners that can make all the difference.
  13. What file are you burning with the RD burner and have you tried the chip in it's intended installation to see if it works? Say Atari XL/XE OS installed in a 800XL or 130XE. Some PC burners have multiple file types Intel, Hex, Binary etc that it can burn in and if you try verifying with a previously burned eprom and have a mismatch in the file type you will get errors.
  14. Not strictly programming...... but an alternative to having to burn 2732 eproms. Use a 2764 and do this trick. You'll need to run this link through a translator.
  15. Was it a 2732 or 2732A? I thought the 2732 required +25V programming voltage. I'm surprised the RD burner was able to push that much voltage.
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