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RE: Again: RS485 line turnaround
Ahh that was it after all. Funny thing is I *had* that code in my
program but remarked out, obviously there must have been another problem
at the time which stopped it working then. I seem to have gone through
all permutations but finally I have 2 wire RS485 going. So I needed
-485 supported in the kernel config (under etrax specific hardware)
-the 485 serial port enabled in the kernel config
-initialisation of the 485 as following:
//Include for ioctl struct
struct rs485_control ctrl485;
ioctl(fd, TIOCSERSETRS485, &ctrl485);
-write to the port using the ioctl method not write()
struct rs485_write tx;
tx.outc_size = 7;
tx.outc = out_buff;
ioctl(fd, TIOCSERWRRS485, &tx);
Thanks Frank, and all others who helped
From: Frank Brown [mailto:firstname.lastname@example.org]
Sent: Thursday, 19 August 2004 4:22 p.m.
Subject: Again: RS485 line turnaround
I went through the same frustration. I ended up
putting some very direct code in one place.
See the prior note about 9th bit routines.
By the way, I used the special RS485 Ioctl
stuff someone built in, not write(...).
> struct rs485_write tx;
> tx.outc_size = 7;
> tx.outc = out_buff;
> ioctl(serial_channel3, TIOCSERWRRS485, &tx);
Look for rs485.h for rs485_write & TIOCSERWRRS485.
I had to do the same bit by bit progress. Sometimes
it feels like the tale about "the kid hitting himself
in the head with a hammer cause it feels so good when
he quits" is not apochryphal at all. But even a herd
of turtles gets there sooner or later.
for Emerson Climate Technology