Normally If you look at the log (dmsg) you should see a line rs485 something. It's a printk that I show when the ioctl work.
And of course you have to configure the pin correctly = pin mode for TX, rx, gpio. Le 8 sept. 2014 17:27, <[email protected]> a écrit : > I've downloaded Robert C Nelson's code and run build_kernel.sh and > install_kernel.sh. I've controlled that sources are patched by rs485 patch. > BBB booted up normally and uname -r says that I am running new kernel. But > I don't have patched kernel headers. I have created serial.h header as > following: > 1 #include <linux/types.h> > 2 > 3 > 4 struct serial_rs485 { > 5 __u32 flags; /* RS485 feature flags */ > 6 #define SER_RS485_ENABLED (1 << 0) /* If enabled > */ > 7 #define SER_RS485_RTS_ON_SEND (1 << 1) /* Logical > level for > 8 RTS pin > when > 9 sending */ > 10 #define SER_RS485_RTS_AFTER_SEND (1 << 2) /* Logical > level for > 11 RTS pin > after sent*/ > 12 #define SER_RS485_RTS_BEFORE_SEND (1 << 3) > 13 #define SER_RS485_USE_GPIO (1 << 5) > 14 //#define SER_RS485_RX_DURING_TX (1 << 4) > 15 __u32 delay_rts_before_send; /* Delay before send > (milliseconds) */ > 16 __u32 delay_rts_after_send; /* Delay after send > (milliseconds) */ > 17 // __u32 padding[5]; /* Memory is cheap, new > structs > 18 __u32 gpio_pin; /* GPIO Pin Index */ > 19 __u32 padding[4]; /* Memory is cheap, new structs > 20 are a royal PITA .. */ > 21 }; > > > and used it in small example program: > #include <fcntl.h> > #include <termios.h> > #include <sys/ioctl.h> > #include <sys/types.h> > #include "serial.h" > //#include <include/uapi/linux/serial.h> > #include <stdio.h> > #include <unistd.h> > > int main() > { > int fd = open("/dev/ttyO4", O_RDWR | O_NOCTTY | O_NDELAY); > if (fd < 0) > { > perror("Error opening tty!"); > return 1; > } > > struct serial_rs485 rs485conf; > > rs485conf.flags |= SER_RS485_ENABLED; > > rs485conf.flags |= SER_RS485_USE_GPIO; > rs485conf.gpio_pin = 9; > rs485conf.flags |= SER_RS485_RTS_ON_SEND; > rs485conf.flags &= ~(SER_RS485_RTS_AFTER_SEND); > rs485conf.delay_rts_before_send = 0; > rs485conf.delay_rts_after_send = 0; > > if (ioctl (fd, TIOCSRS485, &rs485conf) < 0) > { > perror("Bad ioctl"); > } > > struct termios ttyc; > tcgetattr(fd, &ttyc); > > cfsetospeed(&ttyc, B9600); > cfsetispeed(&ttyc, B9600); > ttyc.c_cflag &= ~CRTSCTS; > ttyc.c_cflag |= CS8 | CLOCAL | CREAD; > ttyc.c_cflag |= CRTSCTS; > ttyc.c_cc[VMIN] = 1; > ttyc.c_cc[VTIME] = 5; > tcsetattr(fd, TCSANOW, &ttyc); > > char data = 0xAA; > > int i = 0; > while(i < 10000) > { > if(write(fd, &data, 1) < 1) > { > perror("Error sending char"); > break; > } > > i++; > } > > if (close (fd) < 0) > { > perror("Error closing tty!"); > return 1; > } > > > return 0; > } > but RTS pin stays still LOW. > > > Dne čtvrtek, 4. září 2014 21:51:58 UTC+2 Mickae1 napsal(a): >> >> In the Debian image from Robert C Nelson, the patch rs485 is already >> included. >> Le 4 sept. 2014 20:57, <[email protected]> a écrit : >> >>> Thank you for your answers. The python code is working perfectly. >>> I need to use it in greater C project though. So I am compiling new >>> kernel including RS485 patch. I have tried >>> /opt/scripts/tools/update_kernel.sh >>> hoping that it includes the RS485 patch ...unsuccessfully. >>> I am now following steps from http://jkridner.wordpress.com/ >>> 2014/06/04/yet-another-set-of-notes-on-building-beaglebone-kernel/ >>> >>> Dne středa, 3. září 2014 17:57:53 UTC+2 [email protected] napsal(a): >>>> >>>> Hello, >>>> I'm writing an app for BeagleBoneBlack running debian (3.8.13-bone50). >>>> I would like to use UART4 to communicate with RS485 transmitter over >>>> P9.24(UART4 Tx), P9.26(UART4 Rx) and P8.33 (UART4 RTS). >>>> I've disabled HDMI and enabled overlays BB-UART4 and BB-UART4-RTSCTS >>>> >>>> cat /sys/devices/bone_capemgr.9/slots >>>> 0: 54:PF--- >>>> 1: 55:PF--- >>>> 2: 56:PF--- >>>> 3: 57:PF--- >>>> 4: ff:P-O-L Bone-LT-eMMC-2G,00A0,Texas Instrument,BB-BONE-EMMC-2G >>>> 5: ff:P-O-- Bone-Black-HDMI,00A0,Texas Instrument,BB-BONELT-HDMI >>>> 6: ff:P-O-- Bone-Black-HDMIN,00A0,Texas Instrument,BB-BONELT-HDMIN >>>> 7: ff:P-O-L Override Board Name,00A0,Override Manuf,BB-UART4 >>>> 10: ff:P-O-L Override Board Name,00A0,Override Manuf,BB-UART4-RTSCTS >>>> >>>> cat /proc/tty/driver/OMAP-SERIAL >>>> serinfo:1.0 driver revision: >>>> 0: uart:OMAP UART0 mmio:0x44E09000 irq:72 tx:345 rx:0 RTS|CTS|DTR|DSR >>>> 4: uart:OMAP UART4 mmio:0x481A8000 irq:45 tx:61355 rx:1 brk:1 RTS|DTR| >>>> DSR >>>> >>>> >>>> RS485 transmitter is connected through RS485-USB converter to PC. When >>>> I run screen /dev/ttyO4 9600 +crtscts and periodicaly write some data to >>>> it, PC receives it properly, but RTS line stays constantly low (I'm using >>>> scope on Tx and RTS lines). >>>> I've also tried to write simple C program, using *struct serial_rs485. >>>> *When I write some data over this program, I got response: *Resource >>>> temporarily unavailable* and dmesg says >>>> *omap_uart 481a8000.serial: Must use GPIO for RS485 Support. *When I >>>> tried to use: >>>> struct serial_rs485 rs485conf; >>>> rs485conf.flags |= SER_RS485_USE_GPIO; >>>> rs485conf.gpio_pin = GPIO0_9; >>>> >>>> I got error from gcc that it does not know those macros: >>>> ‘SER_RS485_USE_GPIO’ was not declared in this scope >>>> rs485conf.flags |= SER_RS485_USE_GPIO; >>>> ‘struct serial_rs485’ has no member named ‘gpio_pin’ >>>> rs485conf.gpio_pin = GPIO0_9; >>>> ‘GPIO0_9’ was not declared in this scope >>>> rs485conf.gpio_pin = GPIO0_9; >>>> >>>> Could somebody help me? I have no more 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. >>> >> -- > 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. > -- 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]. 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