I am trying to set up serial communications over the CON10 connector (UART0 pins 4,5,6,8) to another board (BeagleBone Black) to transmit data parsed as strings between the boards.  Based on this link, this should correspond to /dev/ttySAC0.  I have been unsuccessful in achieving communication via these pins and device node.  In using setserial to probe the port settings, I was concerned about the following output:

 

setserial /dev/ttySAC0
/dev/ttySAC0, UART: undefined, Port: 0x0000, IRQ 83

In using dmesg to probe for more information, I found an identifier for SAC0:

dmesg | egrep -i 'serial|tty'
[    1.020896] [c4] 12c00000.serial: ttySAC0 at MMIO 0x12c00000 (irq = 83) is a S3C6400/10

 

but have been unable to locate any definitive information from that identifier to inform my configuration attempts.

Finally, in looking back at the documentation of my OS, I found this link which seems to indicate that there may be an issue with serial communications at the OS level.  The four pin connector mapped to /dev/ttySAC2 works fine, however, so I wasn't sure how far this problem extends.

 

Has anyone used the CON10 serial connection to send and receive data, or run into any similar problems with Jessie on the XU4?

You aware of that TTL logic is 1.8V?

Yes we added a stepdown to the connector cable.