Re: [Gumstix-users] Direct access to registers

[Rob F. <ro...@fa...>]

Felipe,
I guess it comes down to what you need for real time.
I use Verdex with FTDI modules at 1M baud to talk to dynamixels.  With
libFTDI I'm able to get latencies down to 3ms for a ping to any one
dynamixel.  I typically send commands down to 25 dynamixels every 5ms with
no custom kernel mode driver.  I believe the CM-5 or robostix can get
latecies down to about 250us which is useful for a ping but I can't imagine
its all that useful for load or current posiiton.

Just in case this helps, here's libFTDI
http://www.intra2net.com/en/developer/libftdi/ libFTDI 



Felipe Brandão Cavalcanti wrote:
> 
> Hi,
> 
> Is there any way to directly access the PXA270 registers from the user
> space?
> I am writing a real-time application using Xenomai and I need to have
> access
> to the UARTs, bypassing the kernel entirely in order to keep the latencies
> low.
> I tried to write an application that reads/writes directly to the proper
> registers (based on the program found at
> http://docswiki.gumstix.com/index.php/Sample_code/C/gpregs), yet I can't
> get
> a proper reading from the said UART.
> 
> Any ideas on getting direct access to these registers in a clean way?
> 
> Thanks for the help,
>    -Felipe Brandão Cavalcanti
>    LARA - Laboratory of Robotics and Automation
>    Department of Electrical Engineering
>    UnB - University of Brasília, Brazil
>    http://www.lara.unb.br/
> 
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