STM CircleOS forum / mems adc noise followup

ThomasScherrer · 2007-10-31 10:13:50

I have played alot more with the mems project now,
40-50 counts with a resolution count of -1000 to +1000 for +/- 1G
the jitter is 0.05 G in fact really not that much !
and 100% scale is +/- 2G I think
I have tried to down scale the +/-1000 value to 0-128 so I can draw pixels,
please try this with LCD_DrawPixel now you get a nice stable dot in the center of the screen if you add a littlebit of running avarage :-)

Last edited by ThomasScherrer (2007-10-31 11:26:25)

ThomasScherrer · 2007-11-01 15:36:25

all pixels are single individuals, plotted as they come from the mems or system tick and what ever slow me down,
it takes 6 sec to draw 128 pixels at speed 5 = too slow I say.
something must be really bad or with huge wait for something,
I can also see the menu draw and erase to really slow, with such a super cool and fast CPU
I expect handling a tiny display like this should be like 50-500 frames a sec and in full color..

ANYONE ?!?! any idea why it is soo slow ??

PS: I can see the mems values are much more jittery when running on batteryes
compared to run on usb/debug plug.

Last edited by ThomasScherrer (2007-11-02 08:48:09)

obtronix · 2007-12-01 20:36:41

ThomasScherrer :
I have played alot more with the mems project now,
40-50 counts with a resolution count of -1000 to +1000 for +/- 1G
the jitter is 0.05 G in fact really not that much !
and 100% scale is +/- 2G I think
I have tried to down scale the +/-1000 value to 0-128 so I can draw pixels,
please try this with LCD_DrawPixel now you get a nice stable dot in the center of the screen if you add a littlebit of running avarage :-)

the mems device is speced at 1mg resolution, so maybe try putting the core to sleep and read the mems device via DMA while the core is shut down

# 1 2007-10-31 10:13:50 mems adc noise followup (project: Mems 1.1)

mems adc noise followup (project: Mems 1.1)

# 2 2007-11-01 15:36:25 mems adc noise followup (project: Mems 1.1)

Re: mems adc noise followup (project: Mems 1.1)

# 3 2007-12-01 20:36:41 mems adc noise followup (project: Mems 1.1)

Re: mems adc noise followup (project: Mems 1.1)

ThomasScherrer :

Board footer