The signals are probably inverted by the RS232 line driver IC. Thus while
CTS is active low at the DragonBall, it is active high on the external line.
Trevor
----------
From: [EMAIL PROTECTED] [SMTP:[EMAIL PROTECTED]]
Sent: Tuesday, November 14, 2000 12:00 AM
To: Palm Developer Forum
Subject: Re: Invert RTS/CTS flow-control logic?
Well, I don't know anything about hardware (which is odd, since I
work on a
hardware emulator for a living). But I do know what it says in the
Dragonball
manuals:
/CTS Clear To Send
This active-low input controls the transmitter. Normally, the
transmitter
waits until
this signal is active (low) before transmitting a character...
Which seems to me like the device you're dealing with works the same
way as the
Dragonball. What am I missing?
-- Keith Rollin
-- Palm OS Emulator engineer
"Paul Harker" <[EMAIL PROTECTED]> on 11/13/2000 04:55:04 PM
Please respond to "Palm Developer Forum"
<[EMAIL PROTECTED]>
Sent by: "Paul Harker" <[EMAIL PROTECTED]>
To: "Palm Developer Forum" <[EMAIL PROTECTED]>
cc: (Keith Rollin/US/PALM)
Subject: Invert RTS/CTS flow-control logic?
Okay, this is a strange one. I am attempting to interface with an
external
serial device that for some reason was designed with an inverted
logic to
it's flow control input (CTS).
In other words, it reads a LOW on CTS as data transmit enable, and
conversely a HIGH inhibits transmission.
So what I'm trying to find out is if there is by any remote chance
an
elegant way of flipping the Serial Manager's flow control logic so
that the
Palm's RTS state is exactly opposite of what it would "normally" be
to match
this "flipped" CTS device.
I suspect the only way of doing this would be to write a custom
serial
driver, which I suspect is far beyond the scope of this project.
Any ideas?
Paul
--
For information on using the Palm Developer Forums, or to
unsubscribe, please see http://www.palmos.com/dev/tech/support/forums/
--
For information on using the Palm Developer Forums, or to unsubscribe, please see
http://www.palmos.com/dev/tech/support/forums/
