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Re: 2-wire rs-485 problem



On Tue, 2002-04-09 at 00:47, Halvar Helgöy wrote:
> Hello
> 
> We are two students working with a project where we use the Etrax LX to communicate with a 2-wire rs485  bus.We have tried to do the RX/TX switching by using software but without success. If there is anyone having tips or code examples on how to do this we would be very grateful.
> 
>  brdgs
> 
>    /Halvar
> 

This is what I used before:

For writing out of the port, you have to ggle RTS before and after
writing:

int flag = TIOCM_RTS;

ioctl(fd, TIOCMBIC, &flag);

count = write(fd,buf,len);
tcdrain(fd);

ioctl(fd, TIOCMBIS, &flag);


For reading, you just call read().

Ujwal