Re: [uCsimm] new subscriber

From: Jean-Marie Bussat (JMBussat@lbl.gov)
Date: Thu Mar 29 2001 - 17:41:19 EST


Ian Leonard wrote:

> > If I'm not mistaken, the RS 232 interface requires plus and minus
> > voltages between 5vdc and 12vdc. The regulator included in the kit
> > mention above I believe is only a positive linear regulator. How is the
> > negative voltage achieved? (From the Linux workstation RS232 port plus &
> > minus pins?))
>
> Don't know, but it works. I just do the software. I could ask the hardware
> guy here, but then I would have to admit that I don't really know what's
> going on.

The ucsimm has a builtin interface chip that makes the serial
interface RS232 compliant. This chip as an internal voltage
converter that deliver voltages, (almost) compatible with the
RS232 standard, from the 3.3V power supply. By the way, most
of todays PCs accept levels as low as 0/+5V on their serial
interface.

Jean-Marie

-- 
  _______________________________________
 |                                       | 
 | Jean-Marie Bussat                     |
 | Lawrence Berkeley National Laboratory |
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 | Email: JMBussat@lbl.gov               |
 | Phone: (510)-486-5687                 |
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