castan@munnari.oz (Jason Castan) (05/10/88)
I'm currently in the process of writing a SND and FSSD sound utility package. An important feature would be the ability to sample at 22k via one of the serial ports. Does anybody have and ideas (and possibly source) on how this might be done? The 22k rate is faster than the max baud rate allowable, so I imagine that you have to go deeper. Any suggestions, or availability of source code would be greatly appreciated. Jason.
rickk@hpvcla.HP.COM (Rick Klaus) (05/12/88)
You're assuming that the serial ports are RS-232, which is spec'ed to only 20 KBaud. However the MAC ports are RS-422, which is designed to operate at 10 MBaud over distances less than 40 ft. You should have no problem sampling at 22K as long as the external digitizer will drive the line that fast. Hope this helps Rick Klaus hplabs!hpvcla!rickk
pkahn@meridian.ads.com (Phil Kahn) (05/13/88)
In article <2108@munnari.oz> castan@munnari.oz (Jason Castan) writes: >I'm currently in the process of writing a SND and FSSD sound >utility package. An important feature would be the ability to >sample at 22k via one of the serial ports. Does anybody have >and ideas (and possibly source) on how this might be done? > >The 22k rate is faster than the max baud rate allowable, so I >imagine that you have to go deeper. > >Any suggestions, or availability of source code would be greatly >appreciated. > > Jason. To sample at 22Khz, you'll have to directly program the Zilog SCC chip. You can get an SCC manual by contacting Zilog directly (they're in the Sunnyvale/Cupertino, California area). Also take a look at the IM V3. It is a delicate job which will require chip programming, assembly coding, and a good understanding of asynchronous communications in the Mac architecture... If you intend to write this for the Macrecorder, my understanding is that this code is publicly forthcoming. Please keep this net (and me) up to date on the progress of this... Many of us are eagerly awaiting such a utility... pk
oster@dewey.soe.berkeley.edu (David Phillip Oster) (05/15/88)
The code to drive the Impulse Audio Digitizer, sampling at 22khtz, was published more than 18 months ago. It is archived in the usual places.