When you say that the gps works on your windows box, I assume it has an "com" interface, i.e. an RS-232 interface. The BBB does not use this specification. it uses a "3.3v ttl". serial connection.
there are a few differences, a: the voltage levels. RS232 specs allow voltages at least -25 to +25 volt (common is -9 - +9 volts). BBB allows 0-3.3V b: the logic. a '1' on RS-232 is *minus* 3-25 volt. a '1' on BBB is *plus* 3.3 volt. Other things that can go wrong: a: Not using a common ground. i.e only connecting rx and tx and assuming the ground is good. b: Using the wrong frame. 8 or 7 databits, 1, 1.5 or 2 stop bits In all these cases a loopback will work, because the machine uses it's own specs. c; there are crappy RS-232 - "ttl" converters on the market. please look up the RS-232 spec, If you don't know what you are doing you can easily fry the BBB success, LP On Thursday, June 19, 2014 3:49:31 PM UTC+2, Alvin M wrote: > > I'm working on a custom linux distro for our customer product. I've got a > gps that works when I plug it into my windows machine but on linux at the > same baud rate I'm getting gabled output. I've tested it on loopback and it > seems to work fine for loopback other than some extra newlines. I had to > manually set the pins to > > name: uart1_txd.uart1_txd (0x44e10984/0x984 = 0x0040), b NA, t NA > mode: OMAP_MUX_MODE0 | AM33XX_SLEWCTRL_SLOW > signals: uart1_txd | mmc2_sdwp | NA | i2c1_scl | NA | pr1_uart0_txd_mux1 | > NA | gpio0_15 > > name: uart1_rxd.uart1_rxd (0x44e10980/0x980 = 0x0070), b NA, t NA > mode: OMAP_MUX_MODE0 | AM33XX_PIN_INPUT_PULLUP | AM33XX_SLEWCTRL_SLOW > signals: uart1_rxd | mmc1_sdwp | NA | i2c1_sda | NA | pr1_uart0_rxd_mux1 | > NA | gpio0_14 > > > stty settings > speed 9600 baud; line = 0; > intr = ^C; quit = ^\; erase = ^?; kill = ^U; eof = ^D; eol = <undef>; > eol2 = <undef>; swtch = <undef>; start = ^Q; stop = ^S; susp = ^Z; rprnt = > ^R; > werase = ^W; lnext = ^V; flush = ^O; min = 1; time = 0; > > Any Ideas? > -- 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 [email protected]. For more options, visit https://groups.google.com/d/optout.
