November 15, 2019, 10:36:21 am

News:

Have you visited the Allwinner Chipset wiki? - http://linux-sunxi.org/


Multiple UARTs issue - Cubieboard 2

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

Previous topic - Next topic

abhinavgupta

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?

Thanks

tomg

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_para5]
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_para6]
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.