Hi all, 


I'm using the BeagleBone Black board with angstrom Linux with 3.8.13 kernel.

SD card boot.

My goal is to send/receive files via a serial ports UARTx. A BBB send the 
file and another one recives it, both on UART2 without capes. By now i'm 
using some available protocols like lerz and lsz.

It works. Furthermore, as specified at page 3964 of the MPU tecnical 
reference manual (spruh73j.pdf) december 2013 revised, the highest  
available bit rate without errors is 3Mbps.

It's Very fast but .... there's a very high cpu usage when a big file is 
moved from BBB to other one!


For example, a 700MB file size , at the receiver side ,shows a consumption 
of almost 98%. On the transmietter side , about 25%. 


In my opinion , the processor is not exploiting the benefits of the DMA.

I have found a register on the memory mapping of the UART2 that allows to 
set the DMA mode. 

So i have tried to check the status of the register with the devmem2 (same 
as mmap in C ). But i got this response

root@beaglebone:/sys/class > devmem2 0x48024008
/dev/mem opened.
Memory mapped at address 0xb6f10000.
Bus error

I have never seen this problem with gpio bank! It works properly with that 
peripherals.


Can anyone help me? or suggest me another way to check the registers 
properly. 

Thanks in advance

Marco

-- 
For more options, visit http://beagleboard.org/discuss
--- 
You received this message because you are subscribed to the Google Groups 
"BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to beagleboard+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

Reply via email to