Hello.
I am wondering if some one can access UART on Beaglebone AI. I updated *.dts file so I think I got /dev/ttyS1, ttyS2, ttyS3, ttyS4 and ttyS5 on my kernel.
debian@beaglebone:/dev$ ls -al ttyS*
crw------- 1 debian tty 4, 64 Mar 13 01:04 ttyS0
crw-rw---- 1 root dialout 4, 65 Mar 12 22:23 ttyS1
crw-rw---- 1 root dialout 4, 66 Mar 12 22:23 ttyS2
crw-rw---- 1 root dialout 4, 67 Mar 12 22:23 ttyS3
crw-rw---- 1 root dialout 4, 68 Mar 12 22:23 ttyS4
crw-rw---- 1 root dialout 4, 69 Mar 12 22:23 ttyS5
debian@beaglebone:/dev$ dmesg | grep tty
[ 0.000000] Kernel command line: console=ttyS0,115200n8 root=/dev/mmcblk1p1 ro rootfstype=ext4 rootwait coherent_pool=1M net.ifnames=0 rng_core.default_quality=100 quiet
[ 0.931970] console [ttyS0] disabled
[ 0.932020] 4806a000.serial: ttyS0 at MMIO 0x4806a000 (irq = 43, base_baud = 3000000) is a 8250
[ 1.018956] console [ttyS0] enabled
[ 1.019768] 48020000.serial: ttyS2 at MMIO 0x48020000 (irq = 44, base_baud = 3000000) is a 8250
[ 1.020527] 48066000.serial: ttyS4 at MMIO 0x48066000 (irq = 45, base_baud = 3000000) is a 8250
[ 1.021268] 48068000.serial: ttyS5 at MMIO 0x48068000 (irq = 46, base_baud = 3000000) is a 8250
[ 1.021996] 48422000.serial: ttyS1 at MMIO 0x48422000 (irq = 47, base_baud = 3000000) is a 8250
[ 1.022744] 4ae2b000.serial: ttyS3 at MMIO 0x4ae2b000 (irq = 48, base_baud = 3000000) is a 8250
I assume the 48066000.serial: ttyS4 at MMIO 0x48066000 is UART5 based on TI system reference.
So I tried to get signals on P9.11 and P9.13(schematic of BeagleBon AI AM57x page 14 of 19) on Beaglebone AI extension header by the following commands.
debian@beaglebone:/dev$ echo 12345 > /dev/ttyS4
When I check signal via software scope, I can not get any signal change on the pins.
Do I need to activate the UART5 ( or /dev/ttyS4 on my dev structure ) before checking? If yes, how can I do to activate it?
Thank you so much!