Hello again, Using the TestADXL345 example in /apps/tests/z1/Accelerometer I got some numbers for you, basically you can:
- Comment out the delay at /tos/chips/adxl345/adxl345P file in line 787. - Edit the example and start the Accelerometer only once (in boot only), then periodically sample 1 axis As it is the ubr (in /tos/platforms/z1/chips/msp430/usci/Z1UsciP.nc is set to 800, as SMCLK is sourced from the DCO with /1 divider, this gives a rough 10KHz clock (I measured this to be actually 9.8724Khz), giving you a total reading time of 4.84ms (measured just before calling .read() and in readDone() event). Changing the ubr to 80 you can get a 87.912Khz clock (measured), with a reading time of 0.711ms. Hope this helps. Regards, --Antonio On Tue, Apr 16, 2013 at 10:29 PM, Antonio Linan <[email protected]> wrote: > Hola! > > Yes, there might be room for improvement, if you look at the code it has > an active waits (around line 787) that slow the readings but were > necessary at the time, also one could try and configure the I2C module with > different settings (UBR for example) to see if more speed is allowed. I > have planned a revision of the usci driver, so things may change, in the > meantime if you wanna dig a little you are welcome, che :) > > Saludos! > > --Antonio > > > > > > > On Tue, Apr 16, 2013 at 7:16 PM, Martín René <[email protected]> wrote: > >> Sorry that i didn't make the interface problem clear... >> >> The accelerometer is digital using i2c interface, and doesn't provide a >> readstream interface. >> >> With another sensor, we reached high sampling speeds using the >> processor's ADC, but the bus does'nt seem to reach the necessary speeds, >> maybe delays or something else slows down the sampling... >> >> >> Saludos y muchas gracias! >> >> --- >> Martín René Vilugrón >> San Carlos de Bariloche >> Patagonia Argentina >> >> >> On Tue, Apr 16, 2013 at 1:58 PM, Michael Schippling <[email protected]>wrote: >> >>> There are some intriguingly named files containing "Stream" and "DMA" >>> in the ...tinyos-2.x_main/tos/chips/**msp430/adc12 directory. Some of >>> them even have comments which reference TEP documents that might >>> explain what they are trying to do. Maybe one of them will allow >>> you to run the ADC at higher rates... >>> >>> In T1 with the mica's (what I know....) one could free-run a single >>> ADC at low audio rates by bypassing most of TOS. >>> >>> MS >>> >>> >>> >>> On 4/15/2013 1:27 PM, Martín René wrote: >>> >>>> We are currently using the Z1 Motes and sampling at 200Hz without >>>> problems, but we can't raise the sampling speed above said speed without >>>> starting to have problems. We need to sample at 1000Hz and we can't get >>>> there. >>>> >>>> I know that the resources of the platform are scarse, but i know that >>>> the ADC can manage those speeds, and as we don't have a analog >>>> accelerometer we neee to speed up all we can the ADXL. >>>> >>>> Is it possible to sample the accelometer at those speeds? >>>> If it is, ¿how? >>>> >>>> Thanks! and saludos >>>> >>>> --- >>>> Martín René Vilugrón >>>> San Carlos de Bariloche >>>> Patagonia Argentina >>>> >>>> >>>> ______________________________**_________________ >>>> Tinyos-help mailing list >>>> Tinyos-help@millennium.**berkeley.edu<[email protected]> >>>> https://www.millennium.**berkeley.edu/cgi-bin/mailman/** >>>> listinfo/tinyos-help<https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help> >>>> >>>> >> >> _______________________________________________ >> Tinyos-help mailing list >> [email protected] >> https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help >> > > > > -- > -- > Antonio Liñan Colina > R+D+I Engineer > @: [email protected] > @: [email protected] > ------------------------------ > Advancare > T: +34 93 582 02 70 > http://www.advancare.com > http://www.zolertia.com > http://zolertia.sourceforge.net > http://webshop.zolertia.com > -- -- Antonio Liñan Colina R+D+I Engineer @: [email protected] @: [email protected] ------------------------------ Advancare T: +34 93 582 02 70 http://www.advancare.com http://www.zolertia.com http://zolertia.sourceforge.net http://webshop.zolertia.com
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