UART enable

[mikheenk...@gmail.com]

Hello!

I have BBB rev.C, and i need to enable two UARTs for use.

I added to the /boot/uEnv.txt file

cape_enable=capemgr.enable_partno=BB-UART1,BB-UART2

In response to ls - l /dev/ttyO* I get

lrwxrwxrwx 1 root root 5 Oct 17 13:22 /dev/ttyO0 -> ttyS0
lrwxrwxrwx 1 root root 5 Oct 17 13:22 /dev/ttyO1 -> ttyS1
lrwxrwxrwx 1 root root 5 Oct 17 13:22 /dev/ttyO2 -> ttyS2

But after echo -ne '123' > /dev/ttyO2 (ot ttyO1, ttyS1, ttyS2), device connected to serial port not receive anything.

In response to dmesg | grep tty*

I get

[    0.000000] Kernel command line: console=ttyO0,115200n8 capemgr.enable_partno=BB-UART1,BB-UART2 root=UUID=4dfadb43-f008-4c9f-8003-74fa96a8fca8 ro rootfstype=ext4 rootwait coherent_pool=1M quiet cape_universal=enable
[    0.000392] WARNING: Your 'console=ttyO0' has been replaced by 'ttyS0'
[    0.174010] Setting up static identity map for 0x80008240 - 0x8000828c
[    2.969944] pps_core: Software ver. 5.3.6 - Copyright 2005-2007 Rodolfo Giometti <giom...@linux.it>
[    3.500733] SGI XFS with ACLs, security attributes, realtime, no debug enabled
[    3.519677] 44e09000.serial: ttyS0 at MMIO 0x44e09000 (irq = 158, base_baud = 3000000) is a 8250
[    3.527141] console [ttyS0] enabled
[    3.528209] 48022000.serial: ttyS1 at MMIO 0x48022000 (irq = 159, base_baud = 3000000) is a 8250
[    3.529174] 48024000.serial: ttyS2 at MMIO 0x48024000 (irq = 160, base_baud = 3000000) is a 8250
[    4.161179] omap_rtc 44e3e000.rtc: setting system clock to 2000-01-01 00:00:00 UTC (946684800)
[   12.284758] LUN: removable file: /var/cache/doc-beaglebone-getting-started/beaglebone-getting-started-2015-12-04.img

uname -a

Linux beaglebone 4.1.15-ti-rt-r43 #1 SMP PREEMPT RT Thu Jan 21 20:13:58 UTC 2016 armv7l GNU/Linux

I tried to create uEnv.txt file in /boot/uboot/ whith the string cape_enable=capemgr.enable_partno=BB-UART1,BB-UART2.

Tried to append to /etc/default/capemgr  CAPE=BB-UART1, UART2.

But nothing worked out.

Maybe there is a problem with pin configuration?

And what mean /dev/ttyO0 -> ttyS0?

Thanks.

[Stuart Longland]

On 18/10/19 7:13 pm, mikheenk...@gmail.com wrote:
> But after echo -ne '123' > /dev/ttyO2 (ot ttyO1, ttyS1, ttyS2), device
> connected to serial port not receive anything.

Did you also set the baud rate and framing settings?

stty -F /dev/ttyO2 115200

Adjust for your requirements, see `man stty`. Also check pin
configurations to ensure the signals are being routed where you expect.
--
Stuart Longland (aka Redhatter, VK4MSL)

I haven't lost my mind...
...it's backed up on a tape somewhere.