Hello, everyone, I just notify something with the RS485 :
I've made a test programm, and in this programm, I'm sending all the time one byte. With the oscilloscope, I can see that there is a delay between each frame : 100ms . Do you have the same thing ? Micka, On Tue, Sep 9, 2014 at 6:26 PM, Alexander Hiam <[email protected]> wrote: > > > On Tuesday, September 9, 2014 8:09:32 AM UTC-4, [email protected] wrote: >> >> Yes, I can see 'rs485 v1.1'. The python code still works fine out of the >> box. C code Rx and Tx lines work OK but RTS still does nothing. >> When I exported the GPIO9 by hand, dmesg got: >> [ 222.055685] gpio_request: gpio-9 (RS485 TXE) status -16 >> [ 222.055730] omap_uart 481a8000.serial: Could not request GPIO 9 : -16 >> >> That means that 485 kernel support works. Without manually exporting it >> says just "[ 537.089146] rs485 v1.1" and does nothing. >> >> BUT now I've discovered something strange with logical level flags in >> struct serial_rs485, maybe I'm using different header or maybe I don't >> understand it correctly. >> When I changed the SER_RS485_RTS_AFTER_SEND to 0 and >> SER_RS485_RTS_ON_SEND to 0,* it started working fine*. >> That means, when sending data, RTS goes HIGH, after sending, it goes >> immediately LOW , that means, >> I expected setting ON_SEND to 1 and AFTER_SEND to 0, but with this >> setting it just changed from LOW to LOW. >> > > Oh yeah, forgot about that. There's a couple ternary operators in the > driver that I think might be backwards, which makes it the logic levels a > bit counter intuitive. It's: > SER_RS485_ENABLED | SER_RS485_USE_GPIO > for an active high RE/DE signal and: > SER_RS485_ENABLED | SER_RS485_USE_GPIO | SER_RS485_RTS_ON_SEND | > SER_RS485_RTS_AFTER_SEND > for an inverted, active low RE/DE signal. > >> >> Thank you both again for Your valuable help. >> I'm satisfied now :-) >> >> >> Dne pondělí, 8. září 2014 19:12:55 UTC+2 Alexander Hiam napsal(a): >> >> >> >> 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. >> >> Right, it's 'rs485 v1.1'. If you see that in dmesg then the ioctl worked >> and it's almost certainly a pinmux issue. >> >> >> 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 htt <http://beagleboard.org/discuss> >> >> ... > > -- > 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. 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