[CentOS] RS-485 over a half duplex serial in Centos 6.5

Sun Nov 9 06:46:17 UTC 2014
Chris Geldenhuis <chris.gelden at iafrica.com>

Hi Jason,

I don't know what temperature range you want to sense. I have had 
success using I-Button temperature sensors directly on a USB RS232 
connector. With this set up you can have multiple sensors on one line as 
each sensor has a unique address.

The software I used for this was from a book Linux Toys by Christopher 
Negus and Chuck Wolber. ISBN: 0-7645-2508-5

Regards

ChrisG

On 11/09/2014 12:21 AM, Jason Ricles wrote:
> Gotcha and yes that was the problem I was having, I could transmit but
> would just get bounced but what I transmitted due to not being able to
> set transmit mode. So I basically have to use
>
> /drivers/serial/crisv10.c: serial driver used on the Cris ETRAX platform
> /drivers/serial/atmel_serial.c: serial driver used on Atmel platforms
> (AVR32 and AT91 included)
>
> for my drivers. Sorry I am not a fully hardware guy so am a little
> lost at some of this stuff, but I know the software is not working
> since the hardware has no way to know how to interact through
> software.
>
> On Sat, Nov 8, 2014 at 5:16 PM, John R Pierce <pierce at hogranch.com> wrote:
>> On 11/8/2014 1:55 PM, Jason Ricles wrote:
>>> I am not too sure, it is for work and we got a custom board. My co worker
>>> who is more the hardware guy set it up. I did notice it is thin before 3.0
>>> kernal. I saw in the 3.0 kernal they have more support. So we are
>>> basically
>>> up the creek without a paddle with the device and kernal 2.6. Would a
>>> RS-485 to RS-232 converter possibly fix the problems?
>>
>> the problem is, a 232-485 converter needs to be told when to be in transmit
>> vs recieve mode for a half duplex single pair circuit to function.  as that
>> article says, this can be done by using the RS232 RTS signal to control the
>> RS485 line driver, but the linux driver has to know about this and support
>> it.
>>
>>
>>
>>
>> --
>> john r pierce                                      37N 122W
>> somewhere on the middle of the left coast
>>
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