Atari Background Music
I recently bought an Atari 1010 program recorder. I have several Atari programs that play music while loading. I was wondering if it is possible to do this to my own programs.
The Atari cassette system is based on two-track stereo. One track is used to record programs and data by means of audio tones (one frequency for 1, another for 0). The other track can be used to record and play back normal audio. You need to do your recording on another cassette recorder, as there is no provision for the 1010 (or 410) recorder to accept a microphone.
You can turn on or off the cassette motor from a BASIC program with two POKEs: POKE 54018,52 to turn the motor on, and POKE 54018,60 to turn the motor off. When the motor is on, any sound on the audio track will begin to play through the TV speaker. You can use timing loops to synchronize your program with the recorded sound.
The audio track can also be heard during tape operations such as CLOAD, but will be mixed with the normal tones you hear during CLOAD. Use POKE 65,0 to turn off the sound of the data track. You will need to use a stereo cassette recorder to mix programs and sound on the same segment of tape.
You can find more information in COMPUTE!'s First Book of Atari: "Adding a Voice Track to Atari Programs."