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Multiple UARTs issue - Cubieboard 2

Started by abhinavgupta, February 26, 2014, 09:20:47 am

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Hello all,

I am trying to work with UARTs 5 and 6 on my Cubieboard 2.

On boot I get them initialized properly:

dmesg | grep tty
[    0.000000] Kernel command line: console=ttyS0,115200 root=/dev/mmcblk0p1 rootwait loglevel=8 panic=10
[    0.430611] sunxi-uart.0: ttyS0 at MMIO 0x1c28000 (irq = 33) is a U6_16550A
[    1.021764] console [ttyS0] enabled
[    1.052179] sunxi-uart.5: ttyS1 at MMIO 0x1c29400 (irq = 50) is a U6_16550A
[    1.085951] sunxi-uart.6: ttyS2 at MMIO 0x1c29800 (irq = 51) is a U6_16550A
[    6.338913] systemd[1]: Expecting device dev-ttyS0.device...
[    6.675874] systemd[1]: Starting system-getty.slice.
[    6.699364] systemd[1]: Created slice system-getty.slice.
[    6.704839] systemd[1]: Starting system-serial\x2dgetty.slice.
[    6.729370] systemd[1]: Created slice system-serial\x2dgetty.slice.

But when I try to echo something into the tty interfaces, I can't see any transmit/receive happening.

I hooked a CRO to my cubieboard to compare the signal as compared to my A10 board, so here is what happens, when I send something on the UART, the signal goes low and stays there, never comes back, so I am guessing its mostly an issue there. Anyone who has had this issue and can throw some light on the same?



Can you tell me how your script.fex is set up ?
I have set mine up with PI10 PI11 PI12 and PI13 and it seems that they get
initialised fine but when I link tx to rx and test with minicom
I get no data.

I have set up script.fex as follows on the basis that these ports are brought out  to the extension headers
as spi0-cs, spi0-clk, spi0-mosi and spi0-miso.

uart_used = 1
uart_port = 5
uart_type = 2
uart_tx = port:PI10<3><1><default><default>
uart_rx = port:PI11<3><1><default><default>

uart_used = 1
uart_port = 6
uart_type = 2
uart_tx = port:PI12<3><1><default><default>
uart_rx = port:PI14<3><1><default><default>

This set up works fine the minicom program was enabling flow control (HW)
and switching this off solved the problem.