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Sound from the display port

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NathanAllan

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http://wired.hard.ru/data/pin_AudioVideoC64.shtml

According to the pinout above, I should be able to get sound from pin 3, but what about pin 5? Audio in?? Like for a microphone? I can rig something up easily, but wanted to get opinions first. Can I hook up a mic or is that for the return wire from the speaker? I was gonna hook it to ground. I am going to use a CGA monitor with the C128 I just got, but will have to get sound from somewhere else, as the monitor does not have a speaker in it.

Nathan
 
Yes, SID has an audio in which is connected in this port. But beware of the signal levels you feed into it - you might damage the chip if you are not entirely sure what you are doing. I have never tried it myself, but I know the PRG and several other documents describe how you do it.

AFAIR, the signal will be routed directly to the output, so no possibility to read the value and use it for sampling.

While we are on the subject, the VIA/CIA chips in PET/VIC-20/C64 etc has an output on the user port which can be used to generate frequencies in a square wave. Connect a small speaker or buzzer, and you get another sound source. It was rather common on the PET (and possibly other computers with similar possibilities) which has no other sound source.
 
I'm not so interested in a microphone as I am about a decent speaker. I think I wanna pick up a copy of the PRG myself:) Thanks for the reply!

Nathan
 
Yeah, audio out is probably much easier and safer (as long as your speaker or amplifier doesn't drain the source) than using audio in.

Btw, doesn't the CGA monitor plug into the RGB connector rather than the regular video connector, which means you could use a regular five or eight pin DIN -> RCA cable somewhere?
 
Yes, though i am going to make my own cable rather than hunt one down. I have a video connector that is din-rca but want to hang onto it for later use, I might find a real commodore monitor somewhere. I love these things! A friend of mine thinks I am wasting my time "playing with 20 year old technology" but I don't think so. :!: I like making things do what they were never meant to. Contiki!
 
SO as far as I understand, I go from pin 3(audio out) to the speaker to pin 2(ground). Please see the link above in the second post, correct me if I am wrong.
 
I've been comparing pinouts with those pages I linked to in my first posts this thread. Is there a way to adapt RGBI to a VGA monitor? I remember having older monitors that had a VGA connector but with only a few pins. I also have seen that VGA's have the same pins as RGBI but with a few extra. Maybe I should have started a new thread on this question. Refer to the above urls, the pages linked to it in the rest of the site is pretty informative.
 
Supposedly you can connect an CGA (or maybe EGA) monitor to the RGBI on the C128, but you will only get the 80 column output. I don't know to what extent VGA monitors are backwards compatible, but if they were, it would probably be common knowledge if you were able to connect your C128 to a VGA monitor.

Of course, there are small boxes which do composite-to-VGA conversion, often sold when you want to connect your console game to your computer monitor. I don't know how blurry the image is, but IIRC there are some homegrown projects replicating the commercial solutions.
 
I had an old EverVision MN-200 that I tried on it but it didn't work. Apparently if you connect an EGA then the tube grounds out at pin-2 unless I miss my guess(according to the pinout). I think this EverVision is EGA. It might not be any good, I don't have any way to test it out, no other machines and it has no indication on the label as to it being E/CGA. Does anyone here know?? I can't find anything on a google search.

I compared the pins from VGA and CGA and there are some that match up. I have also had monitors in the past that are VGA but only have 6 or 7 pins, must have been converted over. I will try it later with my old Compaq.

I love researching this stuff!!
 
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