Ti 99/4a sound chip

[+TheBF]

2 hours ago, Jamesapp said:

Would you consider the speech synthesizer analog? 
 

and what about using the port the side port for sending line out audio from my digital recorder?

Same concepts apply here.  Digital signals are used to create analog signals that get to transducer (loudspeaker or headphone) make sound waves which are analog meaning not numbers.

So the speech synthesizer is digital of course , internally,  but the audio output is analog. (Analog means continuously changing voltages that change in strength in a way that is "analogous" to the actual sound we hear)

 

It occurs to me now that to people who did not live through the analog to digital transition all these wires in computers and audio devices look similar and so it is easy to assume the carry the same stuff.

It is a remarkable pyramid of stacked technology that takes some time to understand even at the overview level.

[GDMike]

The sid99 is More or less I think what he's looking for?

[Tursi]

20 hours ago, OLD CS1 said:

A quick interrogative: does the audio gate actually get used?  I cannot recall any time when the audio from the cassette port is not heard through the system.

Yes, the cassette is muted during the "PRESS STOP" message in CS1 interaction, for some reason, then IIRC unmuted again after you press Enter. 

 

[+OLD CS1]

1 hour ago, Tursi said:

Yes, the cassette is muted during the "PRESS STOP" message in CS1 interaction, for some reason, then IIRC unmuted again after you press Enter. 

And the remote is turned off at the same time.  We likely would never have known.

[Asmusr]

21 hours ago, Asmusr said:

I tried a few experiments with a little Casio keyboard, a jack to jack cable in the headphone socket of the Casio, and two alligator clips. If I connected the tip of the jack plug at the other end of the cable to the white cassette cable and the sleeve to the red cassette cable (tip or sleeve on the cassette cable didn't matter), I could hear the output from the Casio faintly on my TI. If I connected the tip directly to pin 4 on the cassette port and the sleeve to pin 5, I could hear the output very well. No specific software on the TI was required to hear the output. Connecting only to the white cable didn't work. 

So yes, it should be possible to build a special cable to connect the Casio directly to the joystick port. You need a 9 pin d-sub plug, a jack cable where you cut off one end, and a soldering iron. 

 

19 hours ago, TheBF said:

So nominal line level of .3 volts might be on the low side for the TI.

Using my cheap multimeter, I measure the output from the Casio to 0.2 - 0.4 volts, and that's apparently enough for the audio gate (pin 4 on the cassette port). Listening to the sound from the TI, the Casio is at about the same level as the sounds from a game played at the same time. But someone else should confirm this.

 

Edited September 21, 2022 by Asmusr