multiplexing

[gz]

Hi
have an A20-OLinuXino-Lime2 board and try to use uart3
i noticed that uart3 is multiplexed on gpio1 pins 17,19
according to manual i run ~#olinuxino-overlay and set uart3 enable
when reboot i see that it is ok enabled
also ls-l /dev/ttyS3 outputs
but when i test: echo "some string" > /dev/ttyS3 i detect no activity
on osciloscope???
what am i missing step ?
please help

[LubOlimex]

uart3 is probably not ttyS3 but other check all ttySx

[gz]

you mean? or bigger?
uartX x=1,2

[mactronica]

Hello,
uart3 should be mapped to /dev/ttyS1. Make a test on it.

That is defined in overlay dts https://github.com/OLIMEX/olinuxino-overlays/blob/master/sun7i-a20/sun7i-a20-uart3.dts
Giuseppe.

[Ravor]

you mean? or bigger?
uartX x=1,2

Are the rest of the uarts on? If not, then uart 3 is ttyS1, since ttyS0 is uart0, and uart1 and uart2 are not included.

[LubOlimex]

Are the rest of the uarts on? If not, then uart 3 is ttyS1, since ttyS0 is uart0, and uart1 and uart2 are not included.

Run olinuxino-overlay to check which are enabled and to enable/disable UARTs. Refer to this document:

https://github.com/OLIMEX/OLINUXINO/blob/master/DOCUMENTS/OLIMAGE/Olimage-guide.pdf

[gz]

thank's found ok