You can change /boot/uEnv.txt First of all enable UARTS:
cape_disable=bone_capemgr.disable_partno=BB-BONELT-HDMI,BB-BONELT-HDMIN cape_enable=bone_capemgr.enable_partno=BB-UART1,BB-UART2,BB-UART4.BB-UART5 Then don't forget to configure pinmux with appropriate dtbo's: ###Overide capes with eeprom uboot_overlay_addr0=/lib/firmware/BB-UART1-00A0.dtbo uboot_overlay_addr1=/lib/firmware/BB-UART2-00A0.dtbo uboot_overlay_addr2=/lib/firmware/BB-UART4-00A0.dtbo uboot_overlay_addr3=/lib/firmware/BB-UART5-00A0.dtbo On Thursday, February 9, 2017 at 4:30:23 AM UTC-8, Patrick Oetken wrote: > > Hello! > > I'm trying to use the BeagleBone Black to communicate to RS485 and > CAN-Devices. > For testing I ordered the Waveshare RS485-CAN Cape > <http://www.waveshare.com/rs485-can-cape.htm>. Later on the MAX13487 > should be used for RS485 at UART2. CAN works fine using the BB-CAN1 overlay > with uEnv.txt (UART1). > > But first I tried to communicate from UART1 to UART2, to check if the > UARTs are working. I added BB-UART1, BB-UART2 and BB-UART4 to uEnv.txt and > connected UART1 RX to UART2 TX and UART1 TX to UART2 RX (Pins 22 and 24/ 26 > and 21). > > After Reboot, the UARTs are activated: > > root@beaglebone:/# ls -l /dev/ttyO* > lrwxrwxrwx 1 root root 5 Feb 7 13:55 /dev/ttyO0 -> ttyS0 > lrwxrwxrwx 1 root root 5 Feb 7 13:55 /dev/ttyO1 -> ttyS1 > lrwxrwxrwx 1 root root 5 Feb 7 13:55 /dev/ttyO2 -> ttyS2 > lrwxrwxrwx 1 root root 5 Feb 7 13:55 /dev/ttyO4 -> ttyS4 > > root@beaglebone:/# dmesg | grep tty > [ 0.000000] Kernel command line: console=tty0 console=ttyO0,115200n8 > capemgr.enable_partno=BB-UART1,BB-UART2,BB-UART4, BB-UART5 > root=/dev/mmcblk0p1 > rootfstype=ext4 rootwait coherent_pool=1M quiet cape_universal=enable > [ 0.001090] console [tty0] enabled > [ 0.001109] WARNING: Your 'console=ttyO0' has been replaced by 'ttyS0' > [ 3.929029] 44e09000.serial: ttyS0 at MMIO 0x44e09000 (irq = 158, > base_baud = 3000000) is a 8250 > [ 3.941849] console [ttyS0] enabled > [ 22.142299] 48022000.serial: ttyS1 at MMIO 0x48022000 (irq = 189, > base_baud = 3000000) is a 8250 > [ 22.154538] 48024000.serial: ttyS2 at MMIO 0x48024000 (irq = 190, > base_baud = 3000000) is a 8250 > [ 22.165780] 481a8000.serial: ttyS4 at MMIO 0x481a8000 (irq = 191, > base_baud = 3000000) is a 8250 > > Most tutorials using an older Debian version are using ttyOx to access the > serial ports (old OMAP-driver?), but based on this output I have to use > ttySx with the newer 8250 driver for my commands instead? > > I tried to send/receive messages between the UARTs using minicom, screen > and python scripts, but i can't see any messages at the receiving > interface. Measuring the sending UARTs TX with an oscilloscope I also can't > see any signals. > > At the moment I am running Debian Image 2016-05-13 with Kernel > 4.9.8-bone-rt-r4, I also tried everything with the original Kernel of this > Image (4.4.9?) and a fresh Debian IoT Image 2016-12-09 and also with > UART2+UART4. > > Is there any missing configuration I have to do to get it working? > > -- 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]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/9a1ba5a9-dd65-4cd2-a78b-7222eadc1c26%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
