How to initialize UART5 in Beaglebone?

UART0 is on the WKUP power domain while all the other UARTs are on the PER power domain (in the TRM).  You are probably seeing the UART5 register errors since PER power and clocks are not enabled.

I ran the attached code (from Starterware with UART0) and blindly added UART1 clocking, reset, etc (horribly commented with "jg").  UART1 seems to be alive (and better programmers than me have used this code to get other UART's working on their own AM335x based boards).

Thanks for your reply, I used the code you send me. but still can not access UAER1 registers (0x48022000 address), how I enable the access to them ? (I also can not access any of the UART1-5 registers addreese, tried to add this addresss to gel file, with no success, still can not access). Do you how I should config the control register to allow access to the UART1-5 registers?

Sorry, can't explain why it did not work for you.  After running, I was able to access UART1 registers from Starterware and even from uboot (after a reset, not power down).

Attached are my .out/.msp files for testing.

Hi Joe ,

I read your code and the Technical Reference Manual AM335x document of TI . In the document I see it maybe enable  CM_PER_L4LS_GCLK (OCP) and CM_PER_UART_GFCLK (Func) , but in your code not enable it , so if I want to use uart 1 , should I enable L4LS_GLCK ?

Best Regards

We never actually sent data in or out of UART1, so you could be right that L4_PER_CLK is needed to see data on the pins.

We were just happy to be able to talk to the UART registers.