🚀 go-pugleaf

In article <1992Aug31.230842.11663@Trirex.COM> bmehlman@trirex.com writes:
>I am writing an application that needs to send asynchronous serial data at  
>a speed of 250 Kbps.  Specifically, I'm trying to generate DMX-512  
>standard multimedia device control signals.
>
>This leads to two questions:
>
>1) Can the NeXTs serial ports physically go that fast?
>
>2) Is there any software support for this type of operation?
>
>As far as #2 goes, the NeXT docs and FAQ state that the top supported  
>speed is 38.4...  I'm hoping that there may be others who have written  
>alternative device drivers...


Not with the current drivers.  The current serial drivers generate one
interrupt per character.  At 38.4, this soaks up quite a bit of CPU.
While the Zilog controller is physically capable of high speeds, I
don't know if NeXT's implementation is capable of it (NeXT claims it
cannot do LocalTalk on their serial hardware, and that could be a
reason...).  Furthermore, the hardware interface is not documented and
it may not be possible to write your own drivers that won't step on
the toes of NeXT's...

The DSP can function as a serial port that can go up to something like
138kbps.  Yrrid sells an LKS called TTYDSP that makes the DSP into a
third serial port (DISCLAIMER: I was a beta-tester for TTYDSP) that
will go up to 138k.


I think you best bets would be a NeXTbus card with a serial interface,
a SCSI<->serial interface of some kind, or an ethernet<->serial
interface (do any terminal servers do 250kbps?).


andrew
-- 
andrew@cubetech.com     | "We shall not cease from exploration
Andrew Loewenstern      |  And the end of our exploring
Cube Technologies, Inc. |  Will be to arrive where we started
                        |  And know the place for the first time." -T.S. Eliot

In article <BuFF5t.JnH@ux1.cso.uiuc.edu> jeffo@ux1.cso.uiuc.edu writes:
>andrew@cubetech.com (Andrew Loewenstern) writes:
>>The DSP can function as a serial port that can go up to something like
>>138kbps.  Yrrid sells an LKS called TTYDSP that makes the DSP into a
>>third serial port (DISCLAIMER: I was a beta-tester for TTYDSP) that
>>will go up to 138k.
>
>I've heard about this product and it sounds like the only problem that
>could come up is if I want to use the DSP for something else.  Also, if
>I'm playing music that uses the DSP and this is attached and active,
>could there be problems?  I heard that 3.0 will be able to combine sounds
>from different applications, and to me this sounds like a job the DSP
>would end up doing.  Is that so?
>
>>I think you best bets would be a NeXTbus card with a serial interface,
>>a SCSI<->serial interface of some kind, or an ethernet<->serial
>>interface (do any terminal servers do 250kbps?).
>
>The only serial add-on I know of is an 8-port thing from UNINET (I think
>that's how that is spelled), but I just need one high-speed port.  Any
>suggestions?
>
>Thanks for the information.
>-- 
>-- Jeff (jeffo@uiuc.edu)
>-- No NeXTmail please

In the last "UNIX review" magazine (October, p.59) the "Central Data" advertizes
scsiTerminal Servers. They write about solutions for Sun(s), HP(s), IBM RISC,
386/486 systems, but may be they can prepare something for the NeXT as well ?
Telephone:  800/482-0315

PS.
The baud rates are up to 57.6K, prices reasonable. They will be at the
Unix Expo, booth 120.

	-Z.

andrew@cubetech.com (Andrew Loewenstern) writes:
>The DSP can function as a serial port that can go up to something like
>138kbps.  Yrrid sells an LKS called TTYDSP that makes the DSP into a
>third serial port (DISCLAIMER: I was a beta-tester for TTYDSP) that
>will go up to 138k.

I've heard about this product and it sounds like the only problem that
could come up is if I want to use the DSP for something else.  Also, if
I'm playing music that uses the DSP and this is attached and active,
could there be problems?  I heard that 3.0 will be able to combine sounds
from different applications, and to me this sounds like a job the DSP
would end up doing.  Is that so?

>I think you best bets would be a NeXTbus card with a serial interface,
>a SCSI<->serial interface of some kind, or an ethernet<->serial
>interface (do any terminal servers do 250kbps?).

The only serial add-on I know of is an 8-port thing from UNINET (I think
that's how that is spelled), but I just need one high-speed port.  Any
suggestions?

Thanks for the information.
-- 
-- Jeff (jeffo@uiuc.edu)
-- No NeXTmail please