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姜雪

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[问答]

IIS2DH读取FIFO为什么值的倍数为32?

使用2g刻度采样@ 25Hz,FIFO填充数据,我正在读取内容直到水印。 HR和LPen被禁用。
当Z轴指向地球时,我使用H和L字节获得X轴的以下数据:
DATX = 128
DATX = 128
DATX = 128
DATX = -64
DATX = 192
DATX = -128
DATX = -64
DATX = 0
...
首先,为什么值的倍数为32?第二,为什么芯片仍然不移动时的可变性?我已经使用LIS3DSH几年了所以这个IIS2DH确实是真正的降级,但我必须遗漏一些东西。我现在已多次阅读本手册,但找不到我的问题。
-AP

以上来自于谷歌翻译


以下为原文




With a 2g scale sampling @25Hz the FIFO fills with data and I am reading the contents up to the watermark. HR and LPen are disabled.
With the Z-Axis pointing toward earth I get the following data for the X-Axis using the H and L bytes:
DATX=128

DATX=128

DATX=128

DATX=-64

DATX=192

DATX=-128

DATX=-64

DATX=0

...

First, why are the values multiples of 32? Second, why the variability when the chip is still and not moving? I have been using the LIS3DSH for a couple years now so this IIS2DH is a real downgrade for sure, but I must be missing something. I have read over the manual several times now and can't find my issue.

-AP

回帖(2)

曾玲娟

2018-9-12 10:00:16
这些值实际上是64的倍数,因为FIFO包含10位值。在输出寄存器中调整10位值,即16位。
您应该将值除以64,然后乘以灵敏度。
这种变化是由固有噪声引起的。传感器放置在桌面上的振动也很小。

以上来自于谷歌翻译


以下为原文




The values are actually multiples of 64, because the FIFO contains 10-bits values. 10-bits value are left adjusted in output register which is 16 bits.
You should divide the value by 64 and then multiply by the sensitivity.
The variation is caused by the inherent noise. There could be also small vibration of the desk where the sensor is places.
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姜雪

2018-9-12 10:13:04
啊,当然......我把它视为16位值。现在值的变化也更有意义。感谢您的快速回复!

以上来自于谷歌翻译


以下为原文




Ahh, of course...I was treating it like a 16bit value. The variance in the values also make more sense now. Thanks for the quick reply!
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