I'm really not sure this question at all. UART4 Tx a single wire which is high by default. Put a multimeter on the uart4tx pin to confirm this. If you send data to it then it goes out in blocks of N bits (N normally being 10 - start bit, 8 data bits, stop bit), then returns to the default state of high until the next transmission. http://en.wikipedia.org/wiki/Asynchronous_start-stop
Do you want to send binary data bit-by-bit, as in: write 1 to it, the pin goes high, write 0 and the pin goes low? Then that's not what a UART does - sounds like GPIO to me. Do you want to send the byte 0, as in: start bit, 8 x low bits, stop bit? Then "echo -n \x00 > /dev/ttyO4" should do it. But much easier to do this in C (or any other language) as the ttyO4 is just a file: open it, set it up as a TTY (in C with functions tcsetattr, cfmakeraw etc), then write the zero byte to the stream. On 26 November 2013 14:42, Andrei <andrej.kondrat...@gmail.com> wrote: > Hello Rod, > > Thanks you for the help on this, was really helpful. > But do you know how can I send the binary instead of ascii? (Do I need to > put maybe prefix of SB before the value to send binary?) > > After many unsuccessful attempts of sending binary over UART, I'm looking > at possibility to change the UART MODE described in *TI AM335x ARM A8 > Microprocessors technical reference manual , *maybe this will allow me > to send the binary then. > > > For my project, the transceiver that I wan to connect to UART needs > CMOS/TTL logic. > > > On Monday, 25 November 2013 21:05:16 UTC+1, rod calabio wrote: >> >> Andrei >> >> ascii for "1" is 00110001 >> ascii for Line feed is 00001010 >> >> so you will get >> st=0 >> d0 = 1 >> d1 = 0 >> d2 = 0 >> d3 = 0 >> d4 = 1 >> d5 =1 >> d6 = 0 >> d7 =0 >> sp = 1 >> st = 0 >> d0 = 0 >> d1 = 1 >> d2 = 0 >> d3 = 1 >> d4 - d7 =0 >> sp = 1 >> idle = 1 >> >> -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to beagleboard+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/groups/opt_out. > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
