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I was going to start writing my list of resolutions for 2018. Then I thought about writing about what I didn't accomplish in 2017. Then I decided to just work on programing the interface and get the Atari to read and print the MIDI data stream through the joystick port. I had high hopes of creating a midi monitor that would accept the data and print out the commands as they were received but all that extra code was getting in the way of finding errors. I was happy when I got the Atari8 and Arduino to just reliably print the correct bytes. A SIO cable was to be modified because the SIO2PC dead-ends the SIO chain. I just attached jumper wires with female ends to the 4th and 8th pins on a standard cable. Saved me a lot of plugging and unplugging. I wasn't looking forward to programming the Arduino and Atari 8 because trouble shooting was going to be a painful endeavor. Was it the interface hardware, the Arduino program or the Atari8 program that is the problem. Yes, I had problems with all three and even created more. The Arduino Program. The Arduino performs the following steps. 1. Reads the midi data stream and puts it into a buffer. Continuously. 2. Gets a bit from the buffer. FIFO 3. Sets control pins for the 8 joystick pins 4. Sets trigger to signal that data is ready to be read 5. Waits for Atari to signal it got the data 6. Sets the trigger to signal data not ready 7. Waits for Atari to signal reset the process to step 2. Its simple, when you remember that the logic from the Arduino is inverted. When a pin on the Arduino is set high the transistor in the optocoupler turns on, shorting the pin to ground. Thus making the logic level, read by the Atari, LOW. /* Midi data transfer test 12/2017 * * This program reads midi data then ouputs * the data to the Atari Joystick ports. * * The use of the control lines to the Atari Trigger * and from the cassette motor control line on the SIO * port are used for data flow control. * */ // Atari PORTA(54016) mapped to pins on arduino int porta0 = 4; int porta1 = 5; int porta2 = 6; int porta3 = 7; int porta4 = 8; int porta5 = 9; int porta6 = 10; int porta7 = 11; int DSR = 3; //data set ready int DTR = 12;//Atari ready byte zero = 0; byte tempX = 0; int midiData = 0; //Function to Send a byte to the atari and void sendByte(byte byteToSend){ setPorta(byteToSend); digitalWrite(DSR,LOW); //data ready-Trigger 0 while(digitalRead(DTR) == LOW){} //Wait for Atari to get byte cmc goes low digitalWrite(DSR,HIGH); //data not ready-trigger 1 while(digitalRead(DTR) == HIGH){} //wait for Atari to signal ok to get next byte } void setPorta(byte byteToMap){ // Sets digital pins to transfer data to Atari joystick ports(PORTA) // When digital port high, joystick pin shorted to ground or logic 0 if (byteToMap & B00000001){digitalWrite(porta0,LOW);} else {digitalWrite(porta0,HIGH);} if (byteToMap & B00000010){digitalWrite(porta1,LOW);} else {digitalWrite(porta1,HIGH);} if (byteToMap & B00000100){digitalWrite(porta2,LOW);} else {digitalWrite(porta2,HIGH);} if (byteToMap & B00001000){digitalWrite(porta3,LOW);} else {digitalWrite(porta3,HIGH);} if (byteToMap & B00010000){digitalWrite(porta4,LOW);} else {digitalWrite(porta4,HIGH);} if (byteToMap & B00100000){digitalWrite(porta5,LOW);} else {digitalWrite(porta5,HIGH);} if (byteToMap & B01000000){digitalWrite(porta6,LOW);} else {digitalWrite(porta6,HIGH);} if (byteToMap & B10000000){digitalWrite(porta7,LOW);} else {digitalWrite(porta7,HIGH);} } void setup() { pinMode(porta0,OUTPUT); pinMode(porta1,OUTPUT); pinMode(porta2,OUTPUT); pinMode(porta3,OUTPUT); pinMode(porta4,OUTPUT); pinMode(porta5,OUTPUT); pinMode(porta6,OUTPUT); pinMode(porta7,OUTPUT); pinMode(DSR,OUTPUT); pinMode(DTR,INPUT); Serial.begin(31250); setPorta(zero);// digitalWrite(DSR,HIGH); } void loop() { if (Serial.available()>0){ midiData = Serial.read(); //read MIDI stream tempX = byte(midiData); sendByte(tempX); //Send to Atari } } The Atari Program When the Atari wants data it checks the trigger button to see if there is any to read. If not, this program simply waits for one to show up. 10 GOSUB 29000:REM SET UP VARIABLES 15 POKE PACTL,CMCOFF:REM CAS.OFF 20 IF STRIG(0)=0 THEN GOTO 20:REM WAIT ARDUINO TO SIGNAL DATA READY 30 MIDIDATA=PEEK(PORTA):REM READ 35 ? MIDIDATA;" ";:SOUND 0,200,15,15:SOUND 0,0,0,0:REM SHOW DATA ON SCREEN 40 POKE PACTL,CMCON:REM GOT DATA 60 IF STRIG(0)=1 THEN GOTO 60:REM ARDUINO BUSY GETTING DATA 70 POKE PACTL,CMCOFF:REM TELL ARDUINO TO HOLD DATA UNTILL READY 80 GOTO 20:REM GO WAIT FOR NEXT BYTE TO BE READY 29000 PORTA=54016:REM STICK 0 AND 1 29020 PACTL=54018:REM PORTA CONTROL 29030 CMCON=52:REM CASSETTE MOTOR ON 29040 CMCOFF=60:REM CAS. MOTOR OFF 29050 REM POKE 559,0:REM TRUN OFF SCREEN 29100 RETURN A Casio Keyboard was attached to the interface and data was sent to the Atari and dumped on the screen. The following screen shot shows three 255s that were produced when the Arduino was turned on and the reset button was pushed twice. Then anytime a key was pressed or released a NOTE ON command on channel 0 (144) was sent. You see the 144 then the MIDI key number and then the volume setting. If a volume setting was 0 the key was released. The keyboard is not pressure sensitive so its volume defaults to 100. I didn't see any data being missed by the Atari but it was so slow. I mean, it make 300 baud seem fast. I mean, it was so slow that I tried to turn off the display. I mean, it was soooooo slooooooow that I thought I would have to get out the M65 cartridge. Instead, the program was compiled using the MMG Compiler. The speed improvement was remarkable. I couldn't get the buffer to over flow even when a bunch of keys were pressed and released. Since the digital horn is monophonic, its data output should be manageable even when it is transmitting the breath pressure(after touch) data. I also took the time to load the compiled program onto a Max Flash cartridge. Easily running these programs on computers with out a monitor and disk drive will simplify the hardware setup significantly. There was a problem when the Arduino was powered up, all the joystick pins were reading LOW. This confused the Max Flash menu and the program didn't load when the return was pressed. Pressing the Reset button on the Arduino resets the pins until they are turned off again by void Setup() function and hitting the return key on the Atari before that happens will run the program. Now on to writing the program that actually makes some noise and maybe a little music.

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.